stet_pdf_reader/content/

mod.rs

// stet-pdf-reader
// Copyright (c) 2026 Scott Bowman
// SPDX-License-Identifier: Apache-2.0 OR MIT

//! PDF content stream interpreter.
//!
//! Converts PDF page content into a `DisplayList` for rendering through
//! the existing SkiaDevice pipeline.

pub mod cid_unicode;
pub mod cmap;
pub mod color_space;
pub mod font;
mod gid_maps;
pub mod graphics_state;
mod standard_fonts;

use crate::error::PdfError;
use crate::lexer::{Lexer, Token};
use crate::objects::{PdfDict, PdfObj};
use crate::resolver::Resolver;

use self::color_space::{
    ResolvedColorSpace, painted_channels_for_cs, register_icc_profile, resolve_color_space,
    resolve_color_space_obj, to_image_color_space,
};
use self::graphics_state::{ColorSpaceRef, PdfGraphicsState};

use std::sync::{Arc, Mutex};

use self::font::{FontCache, PdfFont};
use self::graphics_state::{ShadingPatternDL, TilingPattern};
use crate::FontProvider;
use stet_fonts::geometry::{Matrix, PathSegment, PsPath};
use stet_graphics::color::{DashPattern, DeviceColor, FillRule, LineCap, LineJoin};
use stet_graphics::device::{
    ClipParams, FillParams, ImageColorSpace, ImageParams, PatternFillParams, StrokeParams,
    TintLookupTable,
};
use stet_graphics::display_list::{
    DisplayElement, DisplayList, GroupParams, OcgVisibility, SoftMaskParams, SoftMaskSubtype,
};
use stet_graphics::icc::IccCache;

/// One entry on the marked-content stack. Pushed on every BDC/BMC, popped
/// on every EMC — so the stack stays balanced regardless of how OC and
/// non-OC blocks interleave. Only `Ocg` entries swap the display list;
/// `Other` entries carry no state but must still exist so EMC pops the
/// correct frame.
enum MarkedContentFrame {
    /// An `/OC BDC` block: parent display list was swapped out, and the
    /// matching EMC wraps the collected children in an `OcgGroup`.
    Ocg {
        parent_list: DisplayList,
        visibility: OcgVisibility,
    },
    /// Any other BDC (non-OC property reference) or BMC.
    Other,
}

/// Read a numeric array entry, following an indirect reference if needed.
///
/// PDF dict values like `/BBox`, `/Matrix`, `/MediaBox`, etc. are commonly
/// shared across multiple objects via indirect references (e.g. several form
/// XObjects may share a single `/BBox 4 0 R`). `PdfDict::get_array` returns
/// `None` for an indirect-ref value, so callers that need the numbers must
/// dereference first.
fn deref_num_array(resolver: &Resolver, dict: &PdfDict, key: &[u8]) -> Option<Vec<f64>> {
    let obj = dict.get(key)?;
    if let Some(arr) = obj.as_array() {
        return Some(arr.iter().filter_map(|o| o.as_f64()).collect());
    }
    let resolved = resolver.deref(obj).ok()?;
    resolved
        .as_array()
        .map(|a| a.iter().filter_map(|o| o.as_f64()).collect())
}

/// An operand on the content stream operand stack.
#[derive(Clone, Debug)]
pub enum Operand {
    Int(i64),
    Real(f64),
    Name(Vec<u8>),
    Str(Vec<u8>),
    Array(Vec<PdfObj>),
    Dict(PdfDict),
    Bool(bool),
}

impl Operand {
    /// Get numeric value as f64.
    fn as_f64(&self) -> Option<f64> {
        match self {
            Operand::Int(n) => Some(*n as f64),
            Operand::Real(f) => Some(*f),
            _ => None,
        }
    }

    /// Get name bytes.
    fn as_name(&self) -> Option<&[u8]> {
        match self {
            Operand::Name(n) => Some(n),
            _ => None,
        }
    }

    /// Get string bytes.
    #[allow(dead_code)]
    fn as_str(&self) -> Option<&[u8]> {
        match self {
            Operand::Str(s) => Some(s),
            _ => None,
        }
    }
}

/// Cached result of a fully-processed Image XObject.
/// Keyed by obj_num in the content interpreter's `image_cache`.
#[derive(Clone)]
struct CachedImage {
    sample_data: Arc<Vec<u8>>,
    width: u32,
    height: u32,
    color_space: ImageColorSpace,
    bits_per_component: u8,
    interpolate: bool,
    mask_color: Option<Vec<u8>>,
    /// CMYK painted channels derived from the image's own color space.
    painted_channels: u8,
    /// For soft-masked images: (mask_gray_data, mask_width, mask_height, matte).
    smask: Option<(Arc<Vec<u8>>, u32, u32, Option<Vec<f64>>)>,
    /// The image's `/Intent` (or the gstate `/RI` at first emit if absent).
    /// Cached so re-emits keep the same intent — the image-level intent is a
    /// property of the image, not of the gstate at re-use time.
    rendering_intent: u8,
}

/// Tracks the scope of an active soft mask in the display list.
struct SoftMaskScope {
    /// Index in display_list where the mask scope began.
    start_index: usize,
    /// The resolved soft mask (mask display list + params).
    mask: graphics_state::SoftMask,
}

/// PDF content stream interpreter.
pub struct ContentInterpreter<'a> {
    resolver: &'a Resolver<'a>,
    resources: PdfDict,
    gstate_stack: Vec<PdfGraphicsState>,
    gstate: PdfGraphicsState,
    current_path: PsPath,
    current_point: Option<(f64, f64)>,
    subpath_start: Option<(f64, f64)>,
    operand_stack: Vec<Operand>,
    display_list: DisplayList,
    in_text: bool,
    depth: u32,
    /// True inside a Type 3 CharProc that started with `d1`. Per PDF spec 9.6.5,
    /// color operators must be ignored (glyph uses the current text color).
    d1_color_suppressed: bool,
    font_cache: FontCache,
    current_font: Option<Arc<PdfFont>>,
    /// CTM at the start of the current content stream (page or form).
    /// PDF pattern Matrix maps to the "default (initial) coordinate system
    /// of the parent content stream" — for patterns inside Form XObjects,
    /// this includes the form's matrix transform, not just the page CTM.
    content_stream_ctm: Matrix,
    /// The initial page CTM (DPI scaling + Y-flip + CropBox offset).
    /// Never modified after construction. Used by annotation rendering to
    /// position appearance streams relative to the page, not the CTM left
    /// behind by the content stream.
    initial_ctm: Matrix,
    /// ICC color profile cache for ICCBased color space conversions.
    icc_cache: IccCache,
    /// Active soft mask scope: tracks which display list elements fall under the current SMask.
    soft_mask_scope: Option<SoftMaskScope>,
    /// Counter: incremented when the Q handler flushes a gs-set SMask scope
    /// (detected via smask_gen change). Used by resolve_soft_mask to detect
    /// genuine nested mask scopes vs image-level SMasks.
    nested_mask_flush_count: u32,
    /// Optional font data provider for environments without filesystem access.
    font_provider: Option<FontProvider>,
    /// Accumulated text clip path (for text rendering modes 4-7).
    /// Built up during BT..ET, applied as clip at ET.
    text_clip_path: Option<PsPath>,
    /// When true, DeviceRGB colors are round-tripped through the system CMYK
    /// profile (RGB→CMYK→RGB) to match compositing in a DeviceCMYK page group.
    page_group_is_cmyk: bool,
    /// True only when the document declares a PDF/X-style CMYK output intent
    /// (`/OutputIntents` with a CMYK profile). Required (along with
    /// `page_group_is_cmyk`) for the DeviceGray-to-K-only promotion to fire.
    ///
    /// Plain `/Group /CS /DeviceCMYK` without an output intent (e.g.
    /// `pdf_samples/3000_5.pdf`, `pdf_samples/2495.pdf`) signals only that
    /// compositing happens in CMYK space — it does NOT opt the document into
    /// the system CMYK profile's paper white, so a `0.5 g` paint must still
    /// render at exact RGB(128, 128, 128). Documents that DO declare a CMYK
    /// output intent (PDF/X) accept the profile's paper white as their own
    /// and expect DeviceGray to map onto the K plate (GWG 23.0). The narrower
    /// gate matches the existing `cmyk_group_rgb` round-trip's expectation:
    /// that helper takes RGB and rounds it through CMYK→RGB (range-preserving
    /// on a non-PDF/X CMYK group), while this gate switches the source space
    /// from DeviceGray to DeviceCMYK — only correct when the document opts in.
    pdfx_cmyk_intent: bool,
    /// True while parsing an SMask source form's content stream. The
    /// DeviceGray-to-K-only promotion (`gray_paint_for_gstate`,
    /// `cmyk_group_promote_image`, `cmyk_group_promote_color`) must be
    /// suppressed in this context: image color conversion happens at render
    /// time, after the parse-time `suspend_default_cmyk` has been restored,
    /// so a promoted CMYK-K image emitted from an SMask source would later
    /// hit the ICC pipeline and shift the SMask's luminosity (g=255 → CMYK
    /// 0/0/0/0 → ICC RGB ≈ (241,241,241) → alpha ≈ 0.94 instead of 1.0,
    /// regressed `pdf_samples/2495.pdf`'s right-side images). Mirrors the
    /// existing `IccCache::suspend_default_cmyk` precedent at the layer where
    /// the promotion happens — needed even within PDF/X documents (the gate
    /// above doesn't help there; only the SMask context guard does).
    in_smask_form: bool,
    /// When false, PDF overprint flags (OP/op) in graphics state dicts are
    /// suppressed — the gstate overprint fields stay false regardless of PDF content.
    overprint_enabled: bool,
    /// Cache of resolved tiling patterns, keyed by PDF indirect reference (obj_num, gen).
    /// Ensures the same pattern stream is interpreted only once, with the graphics
    /// state from the first resolution (matching GhostScript behaviour).
    pattern_cache: std::collections::HashMap<(u32, u16), TilingPattern>,
    /// Object numbers of Optional Content Groups that are OFF by default.
    ocg_off: std::collections::HashSet<u32>,
    /// Stack of marked-content frames. Every BDC/BMC pushes one frame,
    /// every EMC pops one — keeping the stack balanced even when OC and
    /// non-OC sections interleave. Only `Ocg` frames actually swap the
    /// display list; `Other` frames are placeholders.
    mc_stack: Vec<MarkedContentFrame>,
    /// HashMap index of the current resource dict's ColorSpace sub-dict.
    /// Built lazily on first sc/scn access to avoid O(n) PdfDict scans.
    cs_index: Option<std::collections::HashMap<Vec<u8>, PdfObj>>,
    /// Visible Y range in form coordinates for early culling of offscreen content.
    /// Set when entering a Form XObject whose BBox is much larger than the clip area.
    /// BT/ET blocks whose Y position falls outside this range are skipped.
    form_cull_y: Option<(f64, f64)>,
    /// When true, the current BT/ET block is being skipped (offscreen).
    bt_culled: bool,
    /// Cache of fully-processed Image XObject data, keyed by obj_num.
    /// Avoids re-decompressing and re-converting the same image (e.g.,
    /// Type 3 emoji glyphs that reference the same XObject 73 times).
    image_cache: std::collections::HashMap<u32, CachedImage>,
    /// Cache of pre-sampled spot tint tables, keyed by the colorspace's
    /// canonical identity (Separation name or DeviceN colorant list). The
    /// tint function is expensive to sample (up to 256 evaluations for
    /// Separation, thousands for DeviceN), and many documents paint the same
    /// spot color hundreds of times per page; without this cache every
    /// `sc`/`scn` re-evaluates the same function from scratch.
    spot_tint_table_cache:
        std::collections::HashMap<Vec<u8>, Arc<stet_graphics::device::TintLookupTable>>,
}

impl<'a> ContentInterpreter<'a> {
    /// Create a new interpreter.
    pub fn new(
        resolver: &'a Resolver<'a>,
        resources: PdfDict,
        initial_ctm: Matrix,
        icc_cache: &IccCache,
        font_provider: Option<FontProvider>,
        overprint_enabled: bool,
        ocg_off: &std::collections::HashSet<u32>,
    ) -> Self {
        Self {
            resolver,
            resources,
            gstate_stack: Vec::new(),
            gstate: PdfGraphicsState::new(initial_ctm),
            current_path: PsPath::new(),
            current_point: None,
            subpath_start: None,
            operand_stack: Vec::new(),
            display_list: DisplayList::new(),
            content_stream_ctm: initial_ctm,
            initial_ctm,
            in_text: false,
            depth: 0,
            d1_color_suppressed: false,
            nested_mask_flush_count: 0,
            font_cache: FontCache::new(),
            current_font: None,
            icc_cache: icc_cache.clone(),
            soft_mask_scope: None,
            font_provider,
            text_clip_path: None,
            page_group_is_cmyk: false,
            pdfx_cmyk_intent: false,
            in_smask_form: false,
            overprint_enabled,
            pattern_cache: std::collections::HashMap::new(),
            ocg_off: ocg_off.clone(),
            mc_stack: Vec::new(),
            cs_index: None,
            form_cull_y: None,
            bt_culled: false,
            image_cache: std::collections::HashMap::new(),
            spot_tint_table_cache: std::collections::HashMap::new(),
        }
    }

    /// Mark this page as having a DeviceCMYK transparency group.
    /// DeviceRGB colors will be round-tripped through the ICC CMYK profile
    /// to match compositing in CMYK space (produces more muted, accurate colors).
    pub fn set_page_group_cmyk(&mut self) {
        self.page_group_is_cmyk = true;
    }

    /// Mark this document as declaring a PDF/X-style CMYK output intent. Opts
    /// the document into the DeviceGray-to-K-only promotion required by GWG
    /// 23.0. Plain `/Group /CS /DeviceCMYK` pages should not call this.
    pub fn set_pdfx_cmyk_intent(&mut self) {
        self.pdfx_cmyk_intent = true;
    }

    /// Look up a sub-dictionary in the resources, resolving indirect references.
    /// e.g., `resolve_resource_subdict(b"Font")` returns the /Font dict.
    /// Get an integer value from a dict, resolving indirect references.
    fn resolve_dict_int(&self, dict: &PdfDict, key: &[u8]) -> Option<i64> {
        let obj = dict.get(key)?;
        if let Some(n) = obj.as_int() {
            return Some(n);
        }
        // Resolve indirect reference
        let resolved = self.resolver.deref(obj).ok()?;
        resolved.as_int()
    }

    fn resolve_resource_subdict(&self, key: &[u8]) -> Option<PdfDict> {
        let obj = self.resources.get(key)?;
        // If it's already a dict, return it
        if let Some(d) = obj.as_dict() {
            return Some(d.clone());
        }
        // Otherwise try to resolve the reference
        let resolved = self.resolver.deref(obj).ok()?;
        resolved.as_dict().cloned()
    }

    /// Interpret a content stream and return the display list.
    pub fn interpret(mut self, data: &[u8]) -> Result<DisplayList, PdfError> {
        if let Err(e) = self.interpret_stream(data) {
            eprintln!("warning: content stream error: {}", e);
        }
        // Flush any active soft mask scope
        self.flush_soft_mask();
        // Return partial display list even on error — handles malformed PDFs
        // where flate decompression produces truncated content streams.
        Ok(self.display_list)
    }

    /// Interpret a content stream, keeping the interpreter alive for further use.
    pub fn interpret_stream_public(&mut self, data: &[u8]) -> Result<(), PdfError> {
        self.interpret_stream(data)
    }

    /// Consume the interpreter and return the display list.
    pub fn into_display_list(mut self) -> DisplayList {
        self.flush_soft_mask();
        // Close any unmatched marked-content blocks from unbalanced BDC/EMC
        while let Some(frame) = self.mc_stack.pop() {
            if let MarkedContentFrame::Ocg {
                parent_list,
                visibility,
            } = frame
            {
                let ocg_list = std::mem::replace(&mut self.display_list, parent_list);
                self.display_list.push(DisplayElement::OcgGroup {
                    elements: ocg_list,
                    visibility,
                });
            }
        }
        self.display_list
    }

    /// Unwind any leftover gstate stack entries from unbalanced q/Q.
    /// Some PDFs have more q's than Q's; pop each entry as if Q were called,
    /// restoring clip state at each level so display list clips are correct.
    pub fn unwind_gstate_stack(&mut self) {
        while let Some(saved) = self.gstate_stack.pop() {
            let old_clip_version = self.gstate.clip_path_version;
            self.gstate = saved;
            if self.gstate.clip_path_version != old_clip_version {
                self.restore_clip_from_stack();
            }
        }
    }

    /// Reset clip state before rendering annotations.
    /// This ensures annotations aren't affected by clip regions from the page content.
    pub fn reset_clip_for_annotations(&mut self) {
        self.display_list.push(DisplayElement::InitClip);
        self.gstate.clip_path = None;
        self.gstate.clip_stack.clear();
        self.gstate.clip_path_version += 1;
    }

    /// Render an annotation's normal appearance stream (/AP /N).
    pub fn render_annotation(&mut self, obj_num: u32, gen_num: u16) -> Result<(), PdfError> {
        let annot_obj = self.resolver.resolve(obj_num, gen_num)?;
        let annot_dict = annot_obj
            .as_dict()
            .ok_or(PdfError::Other("annotation not a dict".into()))?;

        let subtype = annot_dict.get_name(b"Subtype").unwrap_or(b"");

        // Check annotation flags (/F). PDF spec Table 165:
        // Bit 1 (0x01) = Invisible, Bit 2 (0x02) = Hidden, Bit 6 (0x20) = NoView.
        // Skip annotations that shouldn't be rendered on screen.
        let flags = annot_dict.get_int(b"F").unwrap_or(0);
        if flags & 0x02 != 0 {
            return Ok(()); // Hidden
        }

        // Get /Rect [llx, lly, urx, ury], normalizing swapped coordinates.
        // Rect may be an indirect reference — resolve before parsing.
        let rect = annot_dict
            .get(b"Rect")
            .and_then(|obj| {
                let resolved = self.resolver.deref(obj).ok().unwrap_or(obj.clone());
                let a = resolved
                    .as_array()
                    .or_else(|| annot_dict.get_array(b"Rect"))?;
                if a.len() >= 4 {
                    let r0 = a[0].as_f64()?;
                    let r1 = a[1].as_f64()?;
                    let r2 = a[2].as_f64()?;
                    let r3 = a[3].as_f64()?;
                    Some([r0.min(r2), r1.min(r3), r0.max(r2), r1.max(r3)])
                } else {
                    None
                }
            })
            .ok_or(PdfError::Other("annotation missing Rect".into()))?;

        // Get /AP dict → /N (normal appearance).
        // If no AP, synthesize appearance from annotation properties.
        let ap_obj = match annot_dict.get(b"AP") {
            Some(ap) => ap,
            None => {
                return self.synthesize_annotation(annot_dict, &rect);
            }
        };
        let ap_dict = match self.resolver.deref(ap_obj)? {
            PdfObj::Dict(d) => d,
            _ => return Err(PdfError::Other("AP not a dict".into())),
        };

        let n_ref = ap_dict.get(b"N").ok_or(PdfError::Other("no AP/N".into()))?;

        // Resolve to get the Form XObject dict + stream.
        // AP/N may be a stream (single appearance) or a dict mapping state
        // names to streams (e.g. checkboxes: << /Yes stream /Off stream >>).
        let n_obj = self.resolver.deref(n_ref)?;
        let (n_ref, form_dict) = if let Some(d) = n_obj.as_dict() {
            if d.get(b"BBox").is_some() {
                // It's a Form XObject stream dict
                (n_ref.clone(), d.clone())
            } else {
                // State-specific appearance dict: pick the entry matching /AS.
                // For Widget annotations (checkboxes/radios), /AS determines
                // which appearance to show (e.g. /Yes = checked, /Off = unchecked).
                // When /AS is absent, default to /Off (unchecked). Only fall back
                // to the first entry for non-Widget annotations.
                let as_name = annot_dict.get_name(b"AS").unwrap_or(b"Off");
                let state_ref = match d.get(as_name) {
                    Some(r) => r,
                    None if subtype == b"Widget" => {
                        // Widget with no matching state — skip rendering
                        return Ok(());
                    }
                    None => {
                        // Non-widget: try the first entry as fallback
                        match d.entries().first().map(|(_, v)| v) {
                            Some(r) => r,
                            None => return Ok(()),
                        }
                    }
                };
                let state_obj = self.resolver.deref(state_ref)?;
                let state_dict = state_obj
                    .as_dict()
                    .ok_or(PdfError::Other("AP/N state not a stream".into()))?;
                (state_ref.clone(), state_dict.clone())
            }
        } else {
            return Err(PdfError::Other("AP/N not a dict or stream".into()));
        };

        // The appearance stream is a Form XObject. Its BBox defines the
        // coordinate space, and we need to map it to the annotation Rect.
        // BBox may be an indirect reference — resolve before accessing.
        let bbox = form_dict
            .get(b"BBox")
            .and_then(|obj| {
                let resolved = self.resolver.deref(obj).ok().unwrap_or(obj.clone());
                let a = resolved.as_array()?;
                if a.len() >= 4 {
                    Some([
                        a[0].as_f64()?,
                        a[1].as_f64()?,
                        a[2].as_f64()?,
                        a[3].as_f64()?,
                    ])
                } else {
                    None
                }
            })
            .unwrap_or([rect[0], rect[1], rect[2], rect[3]]);

        // Apply form's own matrix if present
        let form_matrix = deref_num_array(self.resolver, &form_dict, b"Matrix")
            .and_then(|v| {
                if v.len() == 6 {
                    Some(Matrix::new(v[0], v[1], v[2], v[3], v[4], v[5]))
                } else {
                    None
                }
            })
            .unwrap_or_else(Matrix::identity);

        // Build transform: map the Matrix-transformed BBox → Rect.
        // Per PDF spec 12.5.5, the form's Matrix transforms the BBox into the
        // coordinate system where the appearance was authored. We need to map
        // that transformed extent to the annotation's Rect on the page.
        let (tb0x, tb0y) = form_matrix.transform_point(bbox[0], bbox[1]);
        let (tb1x, tb1y) = form_matrix.transform_point(bbox[2], bbox[3]);
        let tbbox_w = (tb1x - tb0x).abs().max(0.001);
        let tbbox_h = (tb1y - tb0y).abs().max(0.001);
        let rect_w = (rect[2] - rect[0]).abs();
        let rect_h = (rect[3] - rect[1]).abs();
        let sx = rect_w / tbbox_w;
        let sy = rect_h / tbbox_h;
        let tx = rect[0] - tb0x.min(tb1x) * sx;
        let ty = rect[1] - tb0y.min(tb1y) * sy;
        let bbox_to_rect = Matrix::new(sx, 0.0, 0.0, sy, tx, ty);

        // Render as a Form XObject with the computed transform
        let saved_gstate = self.gstate.clone();
        let saved_stack_depth = self.gstate_stack.len();
        let saved_resources = self.resources.clone();
        let saved_mc_stack = std::mem::take(&mut self.mc_stack);
        // Set up resources from the form
        if let Some(res_obj) = form_dict.get(b"Resources")
            && let Ok(PdfObj::Dict(d)) = self.resolver.deref(res_obj)
        {
            self.resources = d;
        }

        // Apply CTM: initial page CTM → bbox_to_rect → form_matrix
        // Use the initial page CTM (not the post-content-stream CTM) because
        // annotation Rects are in page coordinates, not in whatever coordinate
        // system the content stream left behind after cm operations.
        self.gstate.ctm = self.initial_ctm.concat(&bbox_to_rect).concat(&form_matrix);

        // Update content_stream_ctm so shading patterns inside the annotation
        // use the annotation's coordinate system (not the page's).
        let saved_content_stream_ctm = self.content_stream_ctm;
        self.content_stream_ctm = self.gstate.ctm;

        // Note: no BBox clip here — appearance streams do their own internal clipping.

        // Interpret the form content
        let form_data = self.resolver.stream_data_from_obj(&n_ref)?;
        self.depth += 1;
        let _ = self.interpret_stream(&form_data);
        self.depth -= 1;

        // Restore state — truncate gstate stack to handle unbalanced q/Q in stream
        self.gstate_stack.truncate(saved_stack_depth);
        self.content_stream_ctm = saved_content_stream_ctm;
        self.resources = saved_resources;
        self.mc_stack = saved_mc_stack;
        self.gstate = saved_gstate;

        // Restore clip in display list (annotation may have modified clip state)
        self.display_list.push(DisplayElement::InitClip);
        if let Some(ref clip) = self.gstate.clip_path {
            self.display_list.push(DisplayElement::Clip {
                path: clip.clone(),
                params: ClipParams {
                    fill_rule: FillRule::NonZeroWinding,
                    ctm: Matrix::identity(),
                    stroke_params: None,
                },
            });
        }

        Ok(())
    }

    /// Synthesize an appearance for annotations that lack an /AP stream.
    /// Handles Line, PolyLine, Ink, Highlight, StrikeOut, Underline, and Squiggly.
    fn synthesize_annotation(
        &mut self,
        dict: &crate::objects::PdfDict,
        rect: &[f64; 4],
    ) -> Result<(), PdfError> {
        let subtype = dict.get_name(b"Subtype").unwrap_or(b"");

        // Extract annotation color (/C array, default black)
        let color = if let Some(c) = dict.get_array(b"C") {
            let vals: Vec<f64> = c.iter().filter_map(|o| o.as_f64()).collect();
            match vals.len() {
                1 => DeviceColor::from_gray(vals[0]),
                3 => DeviceColor::from_rgb(vals[0], vals[1], vals[2]),
                4 => DeviceColor::from_cmyk(vals[0], vals[1], vals[2], vals[3]),
                _ => DeviceColor::from_gray(0.0),
            }
        } else {
            DeviceColor::from_gray(0.0)
        };

        // Opacity
        let alpha = dict.get(b"CA").and_then(|o| o.as_f64()).unwrap_or(1.0);

        // Border width: prefer /BS dict /W, then /Border array [h_radius v_radius width]
        let border_width = dict
            .get(b"BS")
            .and_then(|bs| self.resolver.deref(bs).ok())
            .and_then(|bs| bs.as_dict().and_then(|d| d.get_f64(b"W")))
            .or_else(|| {
                dict.get_array(b"Border")
                    .and_then(|arr| arr.get(2).and_then(|o| o.as_f64()))
            })
            .unwrap_or(1.0);

        // Dash pattern from /BS /D
        let dash = dict
            .get(b"BS")
            .and_then(|bs| self.resolver.deref(bs).ok())
            .and_then(|bs| {
                let d = bs.as_dict()?;
                let style = d.get_name(b"S")?;
                if style == b"D" {
                    let arr = d
                        .get_array(b"D")
                        .map(|a| a.iter().filter_map(|o| o.as_f64()).collect::<Vec<_>>())
                        .unwrap_or_else(|| vec![3.0]);
                    Some(DashPattern {
                        array: arr,
                        offset: 0.0,
                    })
                } else {
                    None
                }
            })
            .unwrap_or_default();

        let ctm = self.initial_ctm;

        match subtype {
            b"Line" => {
                // /L [x1 y1 x2 y2]
                if let Some(l) = dict.get_array(b"L") {
                    let coords: Vec<f64> = l.iter().filter_map(|o| o.as_f64()).collect();
                    if coords.len() >= 4 {
                        let (x1, y1, x2, y2) = (coords[0], coords[1], coords[2], coords[3]);
                        let path = PsPath {
                            segments: vec![
                                PathSegment::MoveTo(x1, y1),
                                PathSegment::LineTo(x2, y2),
                            ],
                        };
                        self.display_list.push(DisplayElement::Stroke {
                            path,
                            params: StrokeParams {
                                color: color.clone(),
                                line_width: border_width,
                                line_cap: LineCap::Butt,
                                line_join: LineJoin::Miter,
                                miter_limit: 10.0,
                                dash_pattern: dash.clone(),
                                ctm,
                                stroke_adjust: false,
                                is_text_glyph: false,
                                overprint: false,
                                overprint_mode: 0,
                                opm_paired: false,
                                painted_channels: 0,
                                is_device_cmyk: false,
                                spot_color: None,
                                icc_color: None,
                                rendering_intent: 0,
                                transfer: Default::default(),
                                halftone: Default::default(),
                                bg_ucr: Default::default(),
                                alpha,
                                blend_mode: 0,
                                alpha_is_shape: false,
                            },
                        });
                    }
                }
            }
            b"PolyLine" | b"Polygon" => {
                if let Some(verts) = dict.get_array(b"Vertices") {
                    let coords: Vec<f64> = verts.iter().filter_map(|o| o.as_f64()).collect();
                    if coords.len() >= 4 {
                        let mut segs = vec![PathSegment::MoveTo(coords[0], coords[1])];
                        for pair in coords[2..].chunks_exact(2) {
                            segs.push(PathSegment::LineTo(pair[0], pair[1]));
                        }
                        if subtype == b"Polygon" {
                            segs.push(PathSegment::ClosePath);
                        }
                        let path = PsPath { segments: segs };
                        self.display_list.push(DisplayElement::Stroke {
                            path,
                            params: StrokeParams {
                                color: color.clone(),
                                line_width: border_width,
                                line_cap: LineCap::Butt,
                                line_join: LineJoin::Miter,
                                miter_limit: 10.0,
                                dash_pattern: dash.clone(),
                                ctm,
                                stroke_adjust: false,
                                is_text_glyph: false,
                                overprint: false,
                                overprint_mode: 0,
                                opm_paired: false,
                                painted_channels: 0,
                                is_device_cmyk: false,
                                spot_color: None,
                                icc_color: None,
                                rendering_intent: 0,
                                transfer: Default::default(),
                                halftone: Default::default(),
                                bg_ucr: Default::default(),
                                alpha,
                                blend_mode: 0,
                                alpha_is_shape: false,
                            },
                        });
                    }
                }
            }
            b"Ink" => {
                if let Some(ink_list) = dict.get_array(b"InkList") {
                    for stroke_obj in ink_list {
                        let stroke_arr = match stroke_obj {
                            crate::objects::PdfObj::Array(a) => a,
                            _ => continue,
                        };
                        let coords: Vec<f64> =
                            stroke_arr.iter().filter_map(|o| o.as_f64()).collect();
                        if coords.len() >= 4 {
                            let mut segs = vec![PathSegment::MoveTo(coords[0], coords[1])];
                            for pair in coords[2..].chunks_exact(2) {
                                segs.push(PathSegment::LineTo(pair[0], pair[1]));
                            }
                            let path = PsPath { segments: segs };
                            self.display_list.push(DisplayElement::Stroke {
                                path,
                                params: StrokeParams {
                                    color: color.clone(),
                                    line_width: border_width,
                                    line_cap: LineCap::Round,
                                    line_join: LineJoin::Round,
                                    miter_limit: 10.0,
                                    dash_pattern: DashPattern::default(),
                                    ctm,
                                    stroke_adjust: false,
                                    is_text_glyph: false,
                                    overprint: false,
                                    overprint_mode: 0,
                                    opm_paired: false,
                                    painted_channels: 0,
                                    is_device_cmyk: false,
                                    spot_color: None,
                                    icc_color: None,
                                    rendering_intent: 0,
                                    transfer: Default::default(),
                                    halftone: Default::default(),
                                    bg_ucr: Default::default(),
                                    alpha,
                                    blend_mode: 0,
                                    alpha_is_shape: false,
                                },
                            });
                        }
                    }
                }
            }
            b"Highlight" | b"StrikeOut" | b"Underline" | b"Squiggly" => {
                if let Some(qp) = dict.get_array(b"QuadPoints") {
                    let pts: Vec<f64> = qp.iter().filter_map(|o| o.as_f64()).collect();
                    // QuadPoints: groups of 8 (x1,y1, x2,y2, x3,y3, x4,y4)
                    // Order: top-left, top-right, bottom-left, bottom-right
                    for quad in pts.chunks_exact(8) {
                        let (x1, y1) = (quad[0], quad[1]); // top-left
                        let (x2, y2) = (quad[2], quad[3]); // top-right
                        let (x3, y3) = (quad[4], quad[5]); // bottom-left
                        let (x4, y4) = (quad[6], quad[7]); // bottom-right

                        if subtype == b"Highlight" {
                            // Fill the quad with translucent color
                            let path = PsPath {
                                segments: vec![
                                    PathSegment::MoveTo(x1, y1),
                                    PathSegment::LineTo(x2, y2),
                                    PathSegment::LineTo(x4, y4),
                                    PathSegment::LineTo(x3, y3),
                                    PathSegment::ClosePath,
                                ],
                            };
                            self.display_list.push(DisplayElement::Fill {
                                path,
                                params: FillParams {
                                    color: color.clone(),
                                    fill_rule: FillRule::NonZeroWinding,
                                    ctm,
                                    is_text_glyph: false,
                                    overprint: false,
                                    overprint_mode: 0,
                                    opm_paired: false,
                                    painted_channels: 0,
                                    is_device_cmyk: false,
                                    spot_color: None,
                                    icc_color: None,
                                    rendering_intent: 0,
                                    transfer: Default::default(),
                                    halftone: Default::default(),
                                    bg_ucr: Default::default(),
                                    alpha,
                                    blend_mode: 3, // Multiply for highlight
                                    alpha_is_shape: false,
                                },
                            });
                        } else {
                            // StrikeOut/Underline/Squiggly: draw a line
                            let (lx1, ly1, lx2, ly2) = if subtype == b"StrikeOut" {
                                // Middle of the quad
                                (
                                    (x1 + x3) / 2.0,
                                    (y1 + y3) / 2.0,
                                    (x2 + x4) / 2.0,
                                    (y2 + y4) / 2.0,
                                )
                            } else {
                                // Bottom of the quad
                                (x3, y3, x4, y4)
                            };
                            let path = PsPath {
                                segments: vec![
                                    PathSegment::MoveTo(lx1, ly1),
                                    PathSegment::LineTo(lx2, ly2),
                                ],
                            };
                            self.display_list.push(DisplayElement::Stroke {
                                path,
                                params: StrokeParams {
                                    color: color.clone(),
                                    line_width: border_width,
                                    line_cap: LineCap::Butt,
                                    line_join: LineJoin::Miter,
                                    miter_limit: 10.0,
                                    dash_pattern: DashPattern::default(),
                                    ctm,
                                    stroke_adjust: false,
                                    is_text_glyph: false,
                                    overprint: false,
                                    overprint_mode: 0,
                                    opm_paired: false,
                                    painted_channels: 0,
                                    is_device_cmyk: false,
                                    spot_color: None,
                                    icc_color: None,
                                    rendering_intent: 0,
                                    transfer: Default::default(),
                                    halftone: Default::default(),
                                    bg_ucr: Default::default(),
                                    alpha,
                                    blend_mode: 0,
                                    alpha_is_shape: false,
                                },
                            });
                        }
                    }
                }
            }
            b"Square" => {
                // Skip entirely if no border and no interior color
                let has_ic = dict.get_array(b"IC").is_some();
                if border_width < 0.001 && !has_ic {
                    return Ok(());
                }
                let path = PsPath {
                    segments: vec![
                        PathSegment::MoveTo(rect[0], rect[1]),
                        PathSegment::LineTo(rect[2], rect[1]),
                        PathSegment::LineTo(rect[2], rect[3]),
                        PathSegment::LineTo(rect[0], rect[3]),
                        PathSegment::ClosePath,
                    ],
                };
                // Fill with /IC (interior color) if present
                if let Some(ic) = dict.get_array(b"IC") {
                    let vals: Vec<f64> = ic.iter().filter_map(|o| o.as_f64()).collect();
                    let ic_color = match vals.len() {
                        1 => DeviceColor::from_gray(vals[0]),
                        3 => DeviceColor::from_rgb(vals[0], vals[1], vals[2]),
                        4 => DeviceColor::from_cmyk(vals[0], vals[1], vals[2], vals[3]),
                        _ => DeviceColor::from_gray(1.0),
                    };
                    self.display_list.push(DisplayElement::Fill {
                        path: path.clone(),
                        params: FillParams {
                            color: ic_color,
                            fill_rule: FillRule::NonZeroWinding,
                            ctm,
                            is_text_glyph: false,
                            overprint: false,
                            overprint_mode: 0,
                            opm_paired: false,
                            painted_channels: 0,
                            is_device_cmyk: false,
                            spot_color: None,
                            icc_color: None,
                            rendering_intent: 0,
                            transfer: Default::default(),
                            halftone: Default::default(),
                            bg_ucr: Default::default(),
                            alpha,
                            blend_mode: 0,
                            alpha_is_shape: false,
                        },
                    });
                }
                if border_width < 0.001 {
                    return Ok(());
                }
                self.display_list.push(DisplayElement::Stroke {
                    path,
                    params: StrokeParams {
                        color,
                        line_width: border_width,
                        line_cap: LineCap::Butt,
                        line_join: LineJoin::Miter,
                        miter_limit: 10.0,
                        dash_pattern: dash,
                        ctm,
                        stroke_adjust: false,
                        is_text_glyph: false,
                        overprint: false,
                        overprint_mode: 0,
                        opm_paired: false,
                        painted_channels: 0,
                        is_device_cmyk: false,
                        spot_color: None,
                        icc_color: None,
                        rendering_intent: 0,
                        transfer: Default::default(),
                        halftone: Default::default(),
                        bg_ucr: Default::default(),
                        alpha,
                        blend_mode: 0,
                        alpha_is_shape: false,
                    },
                });
            }
            b"Circle" => {
                let has_ic = dict.get_array(b"IC").is_some();
                if border_width < 0.001 && !has_ic {
                    return Ok(());
                }
                // Approximate circle/ellipse with Bezier curves
                let cx = (rect[0] + rect[2]) / 2.0;
                let cy = (rect[1] + rect[3]) / 2.0;
                let rx = (rect[2] - rect[0]) / 2.0;
                let ry = (rect[3] - rect[1]) / 2.0;
                let k = 0.5522847498; // magic number for circular Bezier approximation
                let path = PsPath {
                    segments: vec![
                        PathSegment::MoveTo(cx + rx, cy),
                        PathSegment::CurveTo {
                            x1: cx + rx,
                            y1: cy + ry * k,
                            x2: cx + rx * k,
                            y2: cy + ry,
                            x3: cx,
                            y3: cy + ry,
                        },
                        PathSegment::CurveTo {
                            x1: cx - rx * k,
                            y1: cy + ry,
                            x2: cx - rx,
                            y2: cy + ry * k,
                            x3: cx - rx,
                            y3: cy,
                        },
                        PathSegment::CurveTo {
                            x1: cx - rx,
                            y1: cy - ry * k,
                            x2: cx - rx * k,
                            y2: cy - ry,
                            x3: cx,
                            y3: cy - ry,
                        },
                        PathSegment::CurveTo {
                            x1: cx + rx * k,
                            y1: cy - ry,
                            x2: cx + rx,
                            y2: cy - ry * k,
                            x3: cx + rx,
                            y3: cy,
                        },
                        PathSegment::ClosePath,
                    ],
                };
                if let Some(ic) = dict.get_array(b"IC") {
                    let vals: Vec<f64> = ic.iter().filter_map(|o| o.as_f64()).collect();
                    let ic_color = match vals.len() {
                        1 => DeviceColor::from_gray(vals[0]),
                        3 => DeviceColor::from_rgb(vals[0], vals[1], vals[2]),
                        4 => DeviceColor::from_cmyk(vals[0], vals[1], vals[2], vals[3]),
                        _ => DeviceColor::from_gray(1.0),
                    };
                    self.display_list.push(DisplayElement::Fill {
                        path: path.clone(),
                        params: FillParams {
                            color: ic_color,
                            fill_rule: FillRule::NonZeroWinding,
                            ctm,
                            is_text_glyph: false,
                            overprint: false,
                            overprint_mode: 0,
                            opm_paired: false,
                            painted_channels: 0,
                            is_device_cmyk: false,
                            spot_color: None,
                            icc_color: None,
                            rendering_intent: 0,
                            transfer: Default::default(),
                            halftone: Default::default(),
                            bg_ucr: Default::default(),
                            alpha,
                            blend_mode: 0,
                            alpha_is_shape: false,
                        },
                    });
                }
                if border_width < 0.001 {
                    return Ok(());
                }
                self.display_list.push(DisplayElement::Stroke {
                    path,
                    params: StrokeParams {
                        color,
                        line_width: border_width,
                        line_cap: LineCap::Butt,
                        line_join: LineJoin::Miter,
                        miter_limit: 10.0,
                        dash_pattern: dash,
                        ctm,
                        stroke_adjust: false,
                        is_text_glyph: false,
                        overprint: false,
                        overprint_mode: 0,
                        opm_paired: false,
                        painted_channels: 0,
                        is_device_cmyk: false,
                        spot_color: None,
                        icc_color: None,
                        rendering_intent: 0,
                        transfer: Default::default(),
                        halftone: Default::default(),
                        bg_ucr: Default::default(),
                        alpha,
                        blend_mode: 0,
                        alpha_is_shape: false,
                    },
                });
            }
            _ => {
                // Unsupported annotation type without AP — skip silently
            }
        }

        Ok(())
    }

    /// Interpret content stream bytes (can be called recursively for Form XObjects).
    fn interpret_stream(&mut self, data: &[u8]) -> Result<(), PdfError> {
        // Isolate the operand stack from any caller.  This matters for the
        // recursive entries (Form XObjects, tiling patterns, Type 3 glyphs,
        // soft-mask groups), which are reached via dispatch_operator while
        // the parent's operand stack still has the operator's own operand
        // (e.g. the `/F1` for `Do`) on it.  Without this, the parent operand
        // would be seen by the first operator in the nested stream and
        // (because of the operand-count guard in dispatch_operator) silently
        // drop it.  See circ_compare.pdf reproduction for the original bug.
        let saved_operand_stack = std::mem::take(&mut self.operand_stack);
        let result = self.interpret_stream_inner(data);
        self.operand_stack = saved_operand_stack;
        result
    }

    fn interpret_stream_inner(&mut self, data: &[u8]) -> Result<(), PdfError> {
        let mut lexer = Lexer::new(data);
        // Tracks whether the previous token was a number whose terminating
        // byte was *not* whitespace.  Used to detect lenient lexing of
        // sequences like `5f` (= `5 f`), where the painter is glued to a
        // preceding number with no separator.  pdf.js, GhostScript, hayro,
        // Ocular, and Firefox all interpret these as `<number> <operator>`.
        let mut prev_token_was_glued_number = false;
        loop {
            // Capture position before next_token so we can detect whether the
            // upcoming token is glued to the previous one (no whitespace
            // separator).  If the previous token was a number that ended on a
            // non-whitespace byte, this token is glued to it.
            let pos_before = lexer.pos();
            let glued_to_prev_number = prev_token_was_glued_number
                && pos_before < data.len()
                && !is_whitespace_byte(data[pos_before]);
            let tok = match lexer.next_token() {
                Ok(t) => t,
                Err(_) => {
                    prev_token_was_glued_number = false;
                    continue;
                }
            };
            // Default: clear "glued number" flag.  Set it again below for
            // numeric tokens that ended on a non-whitespace byte.
            prev_token_was_glued_number = false;
            match tok {
                Token::Eof => break,
                Token::Int(n) => {
                    self.operand_stack.push(Operand::Int(n));
                    let p = lexer.pos();
                    prev_token_was_glued_number = p < data.len() && !is_whitespace_byte(data[p]);
                }
                Token::Real(f) => {
                    self.operand_stack.push(Operand::Real(f));
                    let p = lexer.pos();
                    prev_token_was_glued_number = p < data.len() && !is_whitespace_byte(data[p]);
                }
                Token::Name(n) => self.operand_stack.push(Operand::Name(n)),
                Token::LitString(s) | Token::HexString(s) => {
                    self.operand_stack.push(Operand::Str(s));
                }
                Token::Bool(b) => self.operand_stack.push(Operand::Bool(b)),
                Token::ArrayBegin => {
                    let arr = Self::parse_inline_array(&mut lexer)?;
                    self.operand_stack.push(Operand::Array(arr));
                }
                Token::DictBegin => {
                    let dict = crate::lexer::parse_dict_body(&mut lexer)?;
                    self.operand_stack.push(Operand::Dict(dict));
                }
                Token::Keyword(kw) => {
                    // Check for operator suffixes:
                    // * suffix: f*, B*, b*, W*, T*
                    // digit suffix: d0, d1 (Type 3 glyph operators)
                    let op = if matches!(kw.as_slice(), b"f" | b"B" | b"b" | b"W" | b"T") {
                        let p = lexer.pos();
                        if p < data.len() && data[p] == b'*' {
                            lexer.set_pos(p + 1);
                            let mut combined = kw;
                            combined.push(b'*');
                            combined
                        } else {
                            kw
                        }
                    } else if kw == b"d" {
                        let p = lexer.pos();
                        if p < data.len() && (data[p] == b'0' || data[p] == b'1') {
                            lexer.set_pos(p + 1);
                            let mut combined = kw;
                            combined.push(data[p]);
                            combined
                        } else {
                            kw
                        }
                    } else {
                        kw
                    };

                    if op == b"BI" {
                        self.handle_inline_image(&mut lexer)?;
                    } else if let Err(_e) = self.dispatch_operator(&op, glued_to_prev_number) {
                    }
                    self.operand_stack.clear();
                }
                Token::DictEnd | Token::ArrayEnd => {
                    // Stray delimiters — ignore
                }
            }
        }
        Ok(())
    }

    /// Parse an inline array from the content stream.
    fn parse_inline_array(lexer: &mut Lexer) -> Result<Vec<PdfObj>, PdfError> {
        let mut elems = Vec::new();
        loop {
            let tok = lexer.next_token()?;
            match tok {
                Token::ArrayEnd | Token::Eof => break,
                Token::Int(n) => elems.push(PdfObj::Int(n)),
                Token::Real(f) => elems.push(PdfObj::Real(f)),
                Token::Name(n) => elems.push(PdfObj::Name(n)),
                Token::LitString(s) | Token::HexString(s) => elems.push(PdfObj::Str(s)),
                Token::Bool(b) => elems.push(PdfObj::Bool(b)),
                Token::ArrayBegin => {
                    let sub = Self::parse_inline_array(lexer)?;
                    elems.push(PdfObj::Array(sub));
                }
                Token::DictBegin => {
                    let d = crate::lexer::parse_dict_body(lexer).unwrap_or_default();
                    elems.push(PdfObj::Dict(d));
                }
                Token::Keyword(ref kw) if kw == b"null" => {
                    elems.push(PdfObj::Null);
                }
                _ => {}
            }
        }
        Ok(elems)
    }

    /// Dispatch a PDF content stream operator.
    ///
    /// `glued_to_prev_number` is true when the operator token in the source
    /// stream was immediately preceded by a number with no whitespace
    /// separator (e.g. `5f`).  Lenient parsers (pdf.js, GhostScript, hayro,
    /// Ocular, Firefox) all interpret such sequences as `<number> <operator>`,
    /// and this flag lets us bypass the operand-count guard so the painter
    /// still runs.  Without that escape hatch, the guard would silently drop
    /// the painter, leaving the path unpainted (issue994.pdf).
    fn dispatch_operator(&mut self, op: &[u8], glued_to_prev_number: bool) -> Result<(), PdfError> {
        // Path construction and painting operators have fixed operand counts.
        // Excess operands indicate garbled content stream data (e.g. from
        // corrupt FlateDecode) — skip the operator to avoid rendering with
        // wrong coordinates.  The operand stack is cleared after every
        // dispatch, so any values present were pushed since the last operator.
        let expected_args: i32 = match op {
            b"m" | b"l" => 2,
            b"v" | b"y" | b"re" => 4,
            b"c" => 6,
            b"h" | b"S" | b"s" | b"f" | b"F" | b"f*" | b"B" | b"B*" | b"b" | b"b*" | b"n" => 0,
            _ => -1, // no check
        };
        if expected_args >= 0
            && self.operand_stack.len() > expected_args as usize
            && !glued_to_prev_number
        {
            return Ok(());
        }

        // Skip text operators inside a culled BT/ET block (offscreen in large forms)
        if self.bt_culled {
            if op == b"ET" {
                self.bt_culled = false;
                self.in_text = false;
            }
            self.operand_stack.clear();
            return Ok(());
        }

        match op {
            // Graphics state
            b"q" => self.op_q(),
            b"Q" => self.op_big_q(),
            b"cm" => self.op_cm(),
            b"w" => self.op_w(),
            b"J" => self.op_big_j(),
            b"j" => self.op_j(),
            b"M" => self.op_big_m(),
            b"d" => self.op_d(),
            b"ri" => self.op_ri(),
            b"i" => self.op_i(),
            b"gs" => self.op_gs(),

            // Path construction
            b"m" => self.op_m(),
            b"l" => self.op_l(),
            b"c" => self.op_c(),
            b"v" => self.op_v(),
            b"y" => self.op_y(),
            b"h" => self.op_h(),
            b"re" => self.op_re(),

            // Path painting
            b"S" => self.op_big_s(),
            b"s" => self.op_small_s(),
            b"f" | b"F" => self.op_f(),
            b"f*" => self.op_f_star(),
            b"B" => self.op_big_b(),
            b"B*" => self.op_big_b_star(),
            b"b" => self.op_small_b(),
            b"b*" => self.op_small_b_star(),
            b"n" => self.op_n(),

            // Clipping
            b"W" => self.op_big_w(),
            b"W*" => self.op_big_w_star(),

            // Color - device
            b"G" if !self.d1_color_suppressed => self.op_big_g(),
            b"g" if !self.d1_color_suppressed => self.op_small_g(),
            b"RG" if !self.d1_color_suppressed => self.op_big_rg(),
            b"rg" if !self.d1_color_suppressed => self.op_small_rg(),
            b"K" if !self.d1_color_suppressed => self.op_big_k(),
            b"k" if !self.d1_color_suppressed => self.op_small_k(),
            b"G" | b"g" | b"RG" | b"rg" | b"K" | b"k" => Ok(()),

            // Color - general
            b"CS" if !self.d1_color_suppressed => self.op_big_cs(),
            b"cs" if !self.d1_color_suppressed => self.op_small_cs(),
            b"SC" | b"SCN" if !self.d1_color_suppressed => self.op_sc_stroke(),
            b"sc" | b"scn" if !self.d1_color_suppressed => self.op_sc_fill(),
            b"CS" | b"cs" | b"SC" | b"SCN" | b"sc" | b"scn" => Ok(()),

            // Text operators
            b"BT" => {
                self.in_text = true;
                self.gstate.text_matrix = Matrix::identity();
                self.gstate.text_line_matrix = Matrix::identity();
                Ok(())
            }
            b"ET" => {
                self.in_text = false;
                // Apply accumulated text clip path (from rendering modes 4-7)
                if let Some(clip_path) = self.text_clip_path.take()
                    && !clip_path.is_empty()
                {
                    self.display_list.push(DisplayElement::Clip {
                        path: clip_path.clone(),
                        params: ClipParams {
                            fill_rule: FillRule::NonZeroWinding,
                            ctm: Matrix::identity(),
                            stroke_params: None,
                        },
                    });
                    // Track in graphics state so Q/grestore can undo it
                    self.gstate
                        .clip_stack
                        .push((clip_path.clone(), FillRule::NonZeroWinding));
                    self.gstate.clip_path = Some(clip_path);
                    self.gstate.clip_path_version += 1;
                }
                Ok(())
            }
            b"Tf" => self.op_tf(),
            b"Tc" => {
                self.gstate.char_spacing = self.pop_number()?;
                Ok(())
            }
            b"Tw" => {
                self.gstate.word_spacing = self.pop_number()?;
                Ok(())
            }
            b"TL" => {
                self.gstate.text_leading = self.pop_number()?;
                Ok(())
            }
            b"Tr" => {
                self.gstate.text_rendering_mode = self.pop_number()? as i32;
                Ok(())
            }
            b"Ts" => {
                self.gstate.text_rise = self.pop_number()?;
                Ok(())
            }
            b"Tz" => {
                self.gstate.horizontal_scaling = self.pop_number()? / 100.0;
                Ok(())
            }
            b"Td" => self.op_td(),
            b"TD" => self.op_big_td(),
            b"Tm" => self.op_tm(),
            b"T*" => self.op_t_star(),
            b"Tj" => self.op_tj(),
            b"TJ" => self.op_big_tj(),
            b"'" => self.op_quote(),
            b"\"" => self.op_dblquote(),

            // XObject
            b"Do" => self.op_do(),

            // Shading
            b"sh" => self.op_sh(),

            // Marked content with optional content group (OCG) support.
            // BDC/BMC open a section that must be closed by EMC; MP/DP are
            // single-shot marked points with no closing operator.
            b"BMC" => {
                self.operand_stack.pop();
                self.mc_stack.push(MarkedContentFrame::Other);
                Ok(())
            }
            b"MP" => {
                self.operand_stack.pop();
                Ok(())
            }
            b"DP" => {
                self.operand_stack.pop();
                self.operand_stack.pop();
                Ok(())
            }
            b"BDC" => self.op_bdc(),
            b"EMC" => {
                if let Some(MarkedContentFrame::Ocg {
                    parent_list,
                    visibility,
                }) = self.mc_stack.pop()
                {
                    let ocg_list = std::mem::replace(&mut self.display_list, parent_list);
                    self.display_list.push(DisplayElement::OcgGroup {
                        elements: ocg_list,
                        visibility,
                    });
                }
                Ok(())
            }

            // Type 3 glyph operators (width/cache — we use Widths array instead)
            b"d0" => Ok(()),
            b"d1" => {
                // d1: Type 3 glyph with colored content disabled. Per PDF spec
                // 9.6.5, the glyph description shall be treated as a single
                // mask whose source colour is the current colour. Color
                // operators inside the glyph are ignored, AND any path painting
                // operation (fill or stroke) inside the glyph must use the
                // single text color — which for the default text rendering
                // mode 0 is the fill color. Force the stroke color (and any
                // patterns) to match the fill color so a glyph procedure that
                // calls `S` or `b` paints with the fill color, not whatever
                // stroke color happened to be set on the page.
                self.d1_color_suppressed = true;
                self.gstate.stroke_color = self.gstate.fill_color.clone();
                self.gstate.stroke_color_space = self.gstate.fill_color_space.clone();
                self.gstate.stroke_pattern = None;
                self.gstate.stroke_shading_pattern = None;
                self.gstate.stroke_painted_channels = self.gstate.fill_painted_channels;
                self.gstate.stroke_is_device_cmyk = self.gstate.fill_is_device_cmyk;
                self.gstate.stroke_is_none = self.gstate.fill_is_none;
                Ok(())
            }

            // Compatibility (no-op)
            b"BX" | b"EX" => Ok(()),

            _ => {
                // Unknown operator — ignore
                Ok(())
            }
        }
    }

    // === Helper methods ===

    /// Pop one number from the operand stack.
    fn pop_number(&self) -> Result<f64, PdfError> {
        self.operand_stack
            .last()
            .and_then(|o| o.as_f64())
            .ok_or(PdfError::Other("expected number on operand stack".into()))
    }

    /// Get N numbers from the end of the operand stack.
    fn get_numbers(&self, n: usize) -> Result<Vec<f64>, PdfError> {
        let len = self.operand_stack.len();
        if len < n {
            return Err(PdfError::Other(format!("need {n} operands, have {len}")));
        }
        let mut nums = Vec::with_capacity(n);
        for i in (len - n)..len {
            nums.push(
                self.operand_stack[i]
                    .as_f64()
                    .ok_or(PdfError::Other("expected number".into()))?,
            );
        }
        Ok(nums)
    }

    /// Transform a point through the current CTM to device space.
    fn transform(&self, x: f64, y: f64) -> (f64, f64) {
        self.gstate.ctm.transform_point(x, y)
    }

    /// Take the current path and reset it.
    fn take_path(&mut self) -> PsPath {
        let path = std::mem::take(&mut self.current_path);
        self.current_point = None;
        self.subpath_start = None;
        path
    }

    /// Apply pending clip if set, then clear it.
    fn apply_pending_clip(&mut self) {
        if let Some((path, fill_rule)) = self.gstate.pending_clip.take() {
            // A clip path with only MoveTo segments (no lines, curves, or close)
            // has zero area — it clips everything out. Replace with an empty rect
            // so the renderer produces a zero-area clip instead of treating the
            // degenerate path as no-op.
            let has_drawing_segments = path.segments.iter().any(|s| {
                matches!(
                    s,
                    PathSegment::LineTo(..) | PathSegment::CurveTo { .. } | PathSegment::ClosePath
                )
            });
            // A path with MoveTo but no lines/curves has zero area — clip everything.
            // An empty path (no segments at all) is a no-op — skip the clip entirely.
            let has_moveto = path
                .segments
                .iter()
                .any(|s| matches!(s, PathSegment::MoveTo(..)));
            if !has_drawing_segments && has_moveto {
                // Degenerate path (only MoveTo): create a zero-area clip
                let mut empty = PsPath::new();
                empty.segments.push(PathSegment::MoveTo(0.0, 0.0));
                empty.segments.push(PathSegment::LineTo(0.0, 0.0));
                empty.segments.push(PathSegment::ClosePath);
                self.display_list.push(DisplayElement::Clip {
                    path: empty.clone(),
                    params: ClipParams {
                        fill_rule,
                        ctm: Matrix::identity(),
                        stroke_params: None,
                    },
                });
                self.gstate.clip_stack.push((empty.clone(), fill_rule));
                self.gstate.clip_path = Some(empty);
                self.gstate.clip_path_version += 1;
                return;
            }
            if !has_drawing_segments {
                // Empty path: no-op, don't change clip
                return;
            }
            let clip_path = path;
            self.display_list.push(DisplayElement::Clip {
                path: clip_path.clone(),
                params: ClipParams {
                    fill_rule,
                    ctm: Matrix::identity(),
                    stroke_params: None,
                },
            });
            // Track the clip for restoring on Q
            self.gstate.clip_stack.push((clip_path.clone(), fill_rule));
            self.gstate.clip_path = Some(clip_path);
            self.gstate.clip_path_version += 1;
        }
    }

    // === Graphics state operators ===

    fn op_q(&mut self) -> Result<(), PdfError> {
        self.gstate_stack.push(self.gstate.clone());
        Ok(())
    }

    fn op_big_q(&mut self) -> Result<(), PdfError> {
        if let Some(saved) = self.gstate_stack.pop() {
            // Flush soft mask scope if the SMask changed during this q/Q block.
            // Compare the smask_gen counter: if it changed, a new SMask was set
            // inside this block and the scope should be flushed. This correctly
            // handles nested masks inside resolve_soft_mask where both current
            // and saved gstates have a soft_mask but they're different.
            if self.soft_mask_scope.is_some() && self.gstate.smask_gen != saved.smask_gen {
                self.flush_soft_mask();
                self.nested_mask_flush_count += 1;
            }

            let old_clip_version = self.gstate.clip_path_version;
            let old_font_name = std::mem::take(&mut self.gstate.text_font_name);
            self.gstate = saved;
            // If clip changed during the q/Q block, restore it by
            // replaying the full clip stack (not just the last clip).
            if self.gstate.clip_path_version != old_clip_version {
                self.restore_clip_from_stack();
            }
            // Re-resolve current_font if the restored font name differs
            if self.gstate.text_font_name != old_font_name && !self.gstate.text_font_name.is_empty()
            {
                let name = self.gstate.text_font_name.clone();
                self.resolve_current_font(&name);
            }
        }
        Ok(())
    }

    /// Restore the clip state by pushing InitClip + replaying all clips from clip_stack.
    fn restore_clip_from_stack(&mut self) {
        self.display_list.push(DisplayElement::InitClip);
        for (clip, fill_rule) in &self.gstate.clip_stack {
            self.display_list.push(DisplayElement::Clip {
                path: clip.clone(),
                params: ClipParams {
                    fill_rule: *fill_rule,
                    ctm: Matrix::identity(),
                    stroke_params: None,
                },
            });
        }
    }

    fn op_cm(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(6)?;
        let m = Matrix::new(n[0], n[1], n[2], n[3], n[4], n[5]);
        // PDF cm: CTM = CTM × M (pre-multiply, same as PS concat)
        self.gstate.ctm = self.gstate.ctm.concat(&m);
        Ok(())
    }

    fn op_w(&mut self) -> Result<(), PdfError> {
        self.gstate.line_width = self.pop_number()?;
        Ok(())
    }

    fn op_big_j(&mut self) -> Result<(), PdfError> {
        let cap = self.pop_number()? as i32;
        if let Some(lc) = LineCap::from_i32(cap) {
            self.gstate.line_cap = lc;
        }
        Ok(())
    }

    fn op_j(&mut self) -> Result<(), PdfError> {
        let join = self.pop_number()? as i32;
        if let Some(lj) = LineJoin::from_i32(join) {
            self.gstate.line_join = lj;
        }
        Ok(())
    }

    fn op_big_m(&mut self) -> Result<(), PdfError> {
        self.gstate.miter_limit = self.pop_number()?;
        Ok(())
    }

    fn op_d(&mut self) -> Result<(), PdfError> {
        // Operands: array offset
        let len = self.operand_stack.len();
        if len < 2 {
            return Ok(());
        }
        let offset = self.operand_stack[len - 1].as_f64().unwrap_or(0.0);
        let array = match &self.operand_stack[len - 2] {
            Operand::Array(arr) => arr.iter().filter_map(|o| o.as_f64()).collect::<Vec<_>>(),
            _ => Vec::new(),
        };
        self.gstate.dash_pattern = DashPattern { array, offset };
        Ok(())
    }

    fn op_ri(&mut self) -> Result<(), PdfError> {
        // Pop the intent name and translate to the gstate byte code used
        // by the ICC chain dispatch (matches `IccCache::intent_from_pdf_byte`).
        let Some(top) = self.operand_stack.pop() else {
            return Ok(());
        };
        let Some(name) = top.as_name() else {
            return Ok(());
        };
        self.gstate.rendering_intent = match name {
            b"Perceptual" => 0,
            b"RelativeColorimetric" => 1,
            b"Saturation" => 2,
            b"AbsoluteColorimetric" => 3,
            _ => 0,
        };
        Ok(())
    }

    fn op_i(&mut self) -> Result<(), PdfError> {
        self.gstate.flatness = self.pop_number()?;
        Ok(())
    }

    fn op_gs(&mut self) -> Result<(), PdfError> {
        let name = self
            .operand_stack
            .last()
            .and_then(|o| o.as_name())
            .ok_or(PdfError::Other("gs: expected name".into()))?
            .to_vec();
        self.apply_ext_gstate(&name)
    }

    // === Path construction operators ===

    fn op_m(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(2)?;
        let (dx, dy) = self.transform(n[0], n[1]);
        self.current_path.segments.push(PathSegment::MoveTo(dx, dy));
        self.current_point = Some((dx, dy));
        self.subpath_start = Some((dx, dy));
        Ok(())
    }

    fn op_l(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(2)?;
        let (dx, dy) = self.transform(n[0], n[1]);
        self.current_path.segments.push(PathSegment::LineTo(dx, dy));
        self.current_point = Some((dx, dy));
        Ok(())
    }

    fn op_c(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(6)?;
        let (x1, y1) = self.transform(n[0], n[1]);
        let (x2, y2) = self.transform(n[2], n[3]);
        let (x3, y3) = self.transform(n[4], n[5]);
        self.current_path.segments.push(PathSegment::CurveTo {
            x1,
            y1,
            x2,
            y2,
            x3,
            y3,
        });
        self.current_point = Some((x3, y3));
        Ok(())
    }

    fn op_v(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(4)?;
        let (x1, y1) = self.current_point.unwrap_or((0.0, 0.0));
        let (x2, y2) = self.transform(n[0], n[1]);
        let (x3, y3) = self.transform(n[2], n[3]);
        self.current_path.segments.push(PathSegment::CurveTo {
            x1,
            y1,
            x2,
            y2,
            x3,
            y3,
        });
        self.current_point = Some((x3, y3));
        Ok(())
    }

    fn op_y(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(4)?;
        let (x1, y1) = self.transform(n[0], n[1]);
        let (x3, y3) = self.transform(n[2], n[3]);
        self.current_path.segments.push(PathSegment::CurveTo {
            x1,
            y1,
            x2: x3,
            y2: y3,
            x3,
            y3,
        });
        self.current_point = Some((x3, y3));
        Ok(())
    }

    fn op_h(&mut self) -> Result<(), PdfError> {
        self.current_path.segments.push(PathSegment::ClosePath);
        if let Some(start) = self.subpath_start {
            self.current_point = Some(start);
        }
        Ok(())
    }

    fn op_re(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(4)?;
        let (x, y, w, h) = (n[0], n[1], n[2], n[3]);
        // re builds: m x y, l x+w y, l x+w y+h, l x y+h, h
        let p0 = self.transform(x, y);
        let p1 = self.transform(x + w, y);
        let p2 = self.transform(x + w, y + h);
        let p3 = self.transform(x, y + h);
        self.current_path
            .segments
            .push(PathSegment::MoveTo(p0.0, p0.1));
        self.current_path
            .segments
            .push(PathSegment::LineTo(p1.0, p1.1));
        self.current_path
            .segments
            .push(PathSegment::LineTo(p2.0, p2.1));
        self.current_path
            .segments
            .push(PathSegment::LineTo(p3.0, p3.1));
        self.current_path.segments.push(PathSegment::ClosePath);
        self.current_point = Some(p0);
        self.subpath_start = Some(p0);
        Ok(())
    }

    // === Path painting operators ===

    fn op_big_s(&mut self) -> Result<(), PdfError> {
        // S: stroke
        let path = self.take_path();
        if !path.is_empty() {
            self.emit_stroke(path);
        }
        self.apply_pending_clip();
        Ok(())
    }

    fn op_small_s(&mut self) -> Result<(), PdfError> {
        // s: close and stroke
        self.op_h()?;
        self.op_big_s()
    }

    fn op_f(&mut self) -> Result<(), PdfError> {
        // f/F: fill (non-zero winding)
        let path = self.take_path();
        if !path.is_empty() {
            self.emit_fill(path, FillRule::NonZeroWinding);
        }
        self.apply_pending_clip();
        Ok(())
    }

    fn op_f_star(&mut self) -> Result<(), PdfError> {
        // f*: fill (even-odd)
        let path = self.take_path();
        if !path.is_empty() {
            self.emit_fill(path, FillRule::EvenOdd);
        }
        self.apply_pending_clip();
        Ok(())
    }

    fn op_big_b(&mut self) -> Result<(), PdfError> {
        // B: fill (non-zero) + stroke
        let path = self.take_path();
        if !path.is_empty() {
            self.emit_fill_stroke(path, FillRule::NonZeroWinding);
        }
        self.apply_pending_clip();
        Ok(())
    }

    fn op_big_b_star(&mut self) -> Result<(), PdfError> {
        // B*: fill (even-odd) + stroke
        let path = self.take_path();
        if !path.is_empty() {
            self.emit_fill_stroke(path, FillRule::EvenOdd);
        }
        self.apply_pending_clip();
        Ok(())
    }

    fn op_small_b(&mut self) -> Result<(), PdfError> {
        // b: close, fill (non-zero), stroke
        self.op_h()?;
        self.op_big_b()
    }

    fn op_small_b_star(&mut self) -> Result<(), PdfError> {
        // b*: close, fill (even-odd), stroke
        self.op_h()?;
        self.op_big_b_star()
    }

    /// Emit a fill — either a pattern fill or a regular solid fill.
    fn emit_fill(&mut self, path: PsPath, fill_rule: FillRule) {
        if let Some(shading_box) = self.gstate.fill_shading_pattern.clone() {
            // PatternType 2 (shading pattern): clip to fill path, then emit shading.
            // Wrap in a Group to scope the clip — otherwise each shading fill would
            // permanently narrow the clip region, hiding subsequent fills.
            let bbox = path_device_bbox(&path);
            let mut group_dl = DisplayList::new();
            group_dl.push(DisplayElement::Clip {
                path,
                params: ClipParams {
                    fill_rule,
                    ctm: Matrix::identity(),
                    stroke_params: None,
                },
            });
            for elem in shading_box.0.elements() {
                group_dl.push(elem.clone());
            }
            self.display_list.push(DisplayElement::Group {
                elements: group_dl,
                params: GroupParams {
                    bbox,
                    isolated: true,
                    knockout: false,
                    blend_mode: self.gstate.blend_mode,
                    alpha: self.gstate.fill_alpha,
                    color_space: stet_graphics::display_list::GroupColorSpace::Inherited,
                },
            });
        } else if let Some(pattern) = self.gstate.fill_pattern.clone() {
            self.display_list.push(DisplayElement::PatternFill {
                params: PatternFillParams {
                    path,
                    fill_rule,
                    tile: pattern.tile,
                    pattern_matrix: pattern.pattern_matrix,
                    bbox: pattern.bbox,
                    xstep: pattern.x_step,
                    ystep: pattern.y_step,
                    paint_type: pattern.paint_type,
                    underlying_color: if pattern.paint_type == 2 {
                        Some(self.gstate.fill_color.clone())
                    } else {
                        None
                    },
                    pattern_id: pattern.pattern_id,
                    device_space_tile: false,
                    flip_tile_y: false,
                    stroke_params: None,
                    overprint_mode: if self.gstate.overprint {
                        self.gstate.overprint_mode
                    } else {
                        0
                    },
                },
            });
        } else {
            self.display_list.push(DisplayElement::Fill {
                path,
                params: self.gstate.fill_params(fill_rule),
            });
        }
    }

    /// Emit a stroke with proper CTM-aware line width.
    ///
    /// Paths are stored in device space, but strokes need to be applied in user
    /// space for correct anisotropic scaling (non-uniform CTMs make circles into
    /// ellipses, and the stroke width should follow that transformation).
    /// We inverse-transform the path back to user space and pass the CTM to the
    /// renderer so it can apply the stroke correctly.
    fn emit_stroke(&mut self, path: PsPath) {
        let ctm = self.gstate.ctm;
        // Inverse-transform path from device space back to user space
        let user_path = if let Some(inv) = ctm.invert() {
            path.transform(&inv)
        } else {
            path.clone()
        };

        // Tiling pattern stroke: emit PatternFill with stroke_params so the
        // renderer expands the centerline path to a stroke outline for masking.
        if let Some(pattern) = self.gstate.stroke_pattern.clone() {
            let mut sp = self.gstate.stroke_params_with_ctm();
            sp.ctm = ctm;
            self.display_list.push(DisplayElement::PatternFill {
                params: PatternFillParams {
                    path: user_path,
                    fill_rule: FillRule::NonZeroWinding,
                    tile: pattern.tile,
                    pattern_matrix: pattern.pattern_matrix,
                    bbox: pattern.bbox,
                    xstep: pattern.x_step,
                    ystep: pattern.y_step,
                    paint_type: pattern.paint_type,
                    underlying_color: if pattern.paint_type == 2 {
                        Some(self.gstate.stroke_color.clone())
                    } else {
                        None
                    },
                    pattern_id: pattern.pattern_id,
                    device_space_tile: false,
                    flip_tile_y: false,
                    stroke_params: Some(sp),
                    overprint_mode: if self.gstate.overprint {
                        self.gstate.overprint_mode
                    } else {
                        0
                    },
                },
            });
            return;
        }

        // Shading pattern stroke: clip to stroke outline, then emit shading.
        if let Some(shading_box) = self.gstate.stroke_shading_pattern.clone() {
            let mut sp = self.gstate.stroke_params_with_ctm();
            sp.ctm = ctm;
            // Expand the device-space bbox by half the stroke width to account
            // for the area the stroke outline covers beyond the centerline.
            let mut bbox = path_device_bbox(&path);
            let scale = self.gstate.ctm_scale_factor();
            let half_w = self.gstate.line_width * scale * 0.5;
            bbox[0] -= half_w;
            bbox[1] -= half_w;
            bbox[2] += half_w;
            bbox[3] += half_w;
            let mut group_dl = DisplayList::new();
            group_dl.push(DisplayElement::Clip {
                path: user_path,
                params: ClipParams {
                    fill_rule: FillRule::NonZeroWinding,
                    ctm: Matrix::identity(),
                    stroke_params: Some(sp),
                },
            });
            for elem in shading_box.0.elements() {
                group_dl.push(elem.clone());
            }
            self.display_list.push(DisplayElement::Group {
                elements: group_dl,
                params: GroupParams {
                    bbox,
                    isolated: true,
                    knockout: false,
                    blend_mode: self.gstate.blend_mode,
                    alpha: self.gstate.stroke_alpha,
                    color_space: stet_graphics::display_list::GroupColorSpace::Inherited,
                },
            });
            return;
        }

        let mut params = self.gstate.stroke_params_with_ctm();
        params.ctm = ctm;
        self.display_list.push(DisplayElement::Stroke {
            path: user_path,
            params,
        });
    }

    /// Emit fill+stroke atomically: when both are simple (no pattern/shading)
    /// and blend mode is Normal, wrap them in an isolated Group so the stroke
    /// erases the fill's AA edges inside the offscreen buffer before the
    /// combined result composites onto the page. This prevents the fill's
    /// anti-aliased edge pixels from leaking into the pixmap where a
    /// subsequent overprint knockout at a slightly different position would
    /// not fully cover them (GWG 4.0.1 swatch d).
    fn emit_fill_stroke(&mut self, path: PsPath, fill_rule: FillRule) {
        let is_simple_fill =
            self.gstate.fill_shading_pattern.is_none() && self.gstate.fill_pattern.is_none();
        let is_simple_stroke =
            self.gstate.stroke_shading_pattern.is_none() && self.gstate.stroke_pattern.is_none();

        // Group wrapping is safe when the paint's rendering doesn't depend on
        // per-channel backdrop interaction that differs between a real page
        // backdrop and an isolated group's transparent backdrop.
        //
        // - Non-overprint paints always replace the backdrop: safe to group.
        // - Overprint paints can preserve backdrop channels (spot plates,
        //   zero-valued CMYK channels under strict OPM-1). To be safe we
        //   require BOTH fill and stroke to be DeviceCMYK (no Separation /
        //   DeviceN so spot plates aren't involved), the source to be white
        //   (0,0,0,0) so OPM-0 produces a full knockout regardless of
        //   backdrop, and NOT under strict OPM-1 (which would preserve zero
        //   channels and thus depend on the actual backdrop).
        let strict_opm1 = self.gstate.overprint_mode == 1 && self.gstate.opm_paired;
        let is_white_fill = self.gstate.fill_is_device_cmyk
            && self
                .gstate
                .fill_color
                .native_cmyk
                .map(|(c, m, y, k)| c == 0.0 && m == 0.0 && y == 0.0 && k == 0.0)
                .unwrap_or(false);
        let is_white_stroke = self.gstate.stroke_is_device_cmyk
            && self
                .gstate
                .stroke_color
                .native_cmyk
                .map(|(c, m, y, k)| c == 0.0 && m == 0.0 && y == 0.0 && k == 0.0)
                .unwrap_or(false);
        let has_any_overprint = self.gstate.overprint || self.gstate.overprint_stroke;
        // When any overprint is active, require BOTH sides to be DeviceCMYK so
        // spot colorants (which depend on multiplicative backdrop interaction
        // for correct rendering) aren't involved. Mixing a DeviceCMYK overprint
        // fill with a Separation stroke (GWG 4.0.1 swatches a/b/c) would lose
        // the spot backdrop inside the group.
        let both_device_cmyk = self.gstate.fill_is_device_cmyk && self.gstate.stroke_is_device_cmyk;
        let fill_overprint_safe =
            !self.gstate.overprint || (is_white_fill && both_device_cmyk && !strict_opm1);
        let stroke_overprint_safe =
            !self.gstate.overprint_stroke || (is_white_stroke && both_device_cmyk && !strict_opm1);
        // Extra guard: even if each side's own overprint check passes, refuse
        // when *any* overprint is active and the OTHER side isn't DeviceCMYK —
        // this catches the "inherited overprint_stroke=false + Separation
        // stroke + overprint fill" case where the fill alone looks safe.
        let mixed_space_with_overprint = has_any_overprint && !both_device_cmyk;

        if is_simple_fill
            && is_simple_stroke
            && self.gstate.blend_mode == 0
            && fill_overprint_safe
            && stroke_overprint_safe
            && !mixed_space_with_overprint
        {
            let ctm = self.gstate.ctm;

            let mut bbox = path_device_bbox(&path);
            let scale = self.gstate.ctm_scale_factor();
            let half_w = self.gstate.line_width * scale * 0.5;
            bbox[0] -= half_w;
            bbox[1] -= half_w;
            bbox[2] += half_w;
            bbox[3] += half_w;

            let fill_elem = DisplayElement::Fill {
                path: path.clone(),
                params: self.gstate.fill_params(fill_rule),
            };

            let user_path = if let Some(inv) = ctm.invert() {
                path.transform(&inv)
            } else {
                path.clone()
            };
            let mut stroke_params = self.gstate.stroke_params_with_ctm();
            stroke_params.ctm = ctm;
            let stroke_elem = DisplayElement::Stroke {
                path: user_path,
                params: stroke_params,
            };

            let mut group_dl = DisplayList::new();
            group_dl.push(fill_elem);
            group_dl.push(stroke_elem);

            self.display_list.push(DisplayElement::Group {
                elements: group_dl,
                params: stet_graphics::display_list::GroupParams {
                    bbox,
                    isolated: true,
                    knockout: false,
                    blend_mode: 0,
                    alpha: 1.0,
                    color_space: stet_graphics::display_list::GroupColorSpace::Inherited,
                },
            });
        } else {
            self.emit_fill(path.clone(), fill_rule);
            self.emit_stroke(path);
        }
    }

    fn op_n(&mut self) -> Result<(), PdfError> {
        // n: end path (no paint) — used for clip-only paths
        let _path = self.take_path();
        self.apply_pending_clip();
        Ok(())
    }

    // === Clipping operators ===

    fn op_big_w(&mut self) -> Result<(), PdfError> {
        // W: clip (non-zero winding), deferred to next paint op
        self.gstate.pending_clip = Some((self.current_path.clone(), FillRule::NonZeroWinding));
        Ok(())
    }

    fn op_big_w_star(&mut self) -> Result<(), PdfError> {
        // W*: clip (even-odd), deferred to next paint op
        self.gstate.pending_clip = Some((self.current_path.clone(), FillRule::EvenOdd));
        Ok(())
    }

    // === Device color operators ===

    fn op_big_g(&mut self) -> Result<(), PdfError> {
        // G gray: set stroke color to gray
        let g = self.pop_number()?;
        let (color, painted, is_cmyk) = self.gray_paint_for_gstate(g);
        self.gstate.stroke_color = color;
        self.gstate.stroke_color_space = ColorSpaceRef::DeviceGray;
        self.gstate.stroke_painted_channels = painted;
        self.gstate.stroke_is_device_cmyk = is_cmyk;
        self.gstate.stroke_is_none = false;
        self.gstate.stroke_spot_color = None;
        self.gstate.stroke_icc_color = None;
        self.gstate.stroke_pattern = None;
        self.gstate.stroke_shading_pattern = None;
        Ok(())
    }

    fn op_small_g(&mut self) -> Result<(), PdfError> {
        // g gray: set fill color to gray
        let g = self.pop_number()?;
        let (color, painted, is_cmyk) = self.gray_paint_for_gstate(g);
        self.gstate.fill_color = color;
        self.gstate.fill_color_space = ColorSpaceRef::DeviceGray;
        self.gstate.fill_painted_channels = painted;
        self.gstate.fill_is_device_cmyk = is_cmyk;
        self.gstate.fill_is_none = false;
        self.gstate.fill_spot_color = None;
        self.gstate.fill_icc_color = None;
        self.gstate.fill_pattern = None;
        self.gstate.fill_shading_pattern = None;
        Ok(())
    }

    /// Build the gstate fields for a DeviceGray paint. In a CMYK page group
    /// the gray is promoted to a K-only DeviceCMYK paint so the rendering
    /// pipeline composites it identically to `0 0 0 (1−g) k` — matches PDF/X
    /// semantics where DeviceGray maps onto the K plate (GWG 23.0). The
    /// promoted paint still carries `painted_channels = CMYK_K` so the
    /// overprint dispatcher routes it through the K-only subset path,
    /// preserving the overprint-vs-spot behaviour the standalone gray
    /// promotion (GWG 3.0 b/h) needs.
    fn gray_paint_for_gstate(&mut self, g: f64) -> (DeviceColor, u8, bool) {
        if self.pdfx_cmyk_intent && !self.in_smask_form {
            let k = (1.0 - g).clamp(0.0, 1.0);
            let color = DeviceColor::from_cmyk_icc(0.0, 0.0, 0.0, k, &mut self.icc_cache);
            (color, stet_graphics::device::CMYK_K, true)
        } else {
            (DeviceColor::from_gray(g), 0, false)
        }
    }

    fn op_big_rg(&mut self) -> Result<(), PdfError> {
        // RG r g b: set stroke color to RGB
        let n = self.get_numbers(3)?;
        let (r, g, b) = self.cmyk_group_rgb(n[0], n[1], n[2]);
        self.gstate.stroke_color = DeviceColor::from_rgb(r, g, b);
        self.gstate.stroke_color_space = ColorSpaceRef::DeviceRGB;
        self.gstate.stroke_painted_channels = 0;
        self.gstate.stroke_is_device_cmyk = false;
        self.gstate.stroke_is_none = false;
        self.gstate.stroke_spot_color = None;
        self.gstate.stroke_icc_color = None;
        self.gstate.stroke_pattern = None;
        self.gstate.stroke_shading_pattern = None;
        Ok(())
    }

    fn op_small_rg(&mut self) -> Result<(), PdfError> {
        // rg r g b: set fill color to RGB
        let n = self.get_numbers(3)?;
        let (r, g, b) = self.cmyk_group_rgb(n[0], n[1], n[2]);
        self.gstate.fill_color = DeviceColor::from_rgb(r, g, b);
        self.gstate.fill_color_space = ColorSpaceRef::DeviceRGB;
        self.gstate.fill_painted_channels = 0;
        self.gstate.fill_is_device_cmyk = false;
        self.gstate.fill_is_none = false;
        self.gstate.fill_spot_color = None;
        self.gstate.fill_icc_color = None;
        self.gstate.fill_pattern = None;
        self.gstate.fill_shading_pattern = None;
        Ok(())
    }

    /// When the page group is DeviceCMYK, round-trip RGB through the CMYK
    /// profile to simulate compositing in CMYK space.
    fn cmyk_group_rgb(&mut self, r: f64, g: f64, b: f64) -> (f64, f64, f64) {
        if self.page_group_is_cmyk {
            if let Some(result) = self.icc_cache.round_trip_rgb_via_cmyk(r, g, b) {
                return result;
            }
        }
        (r, g, b)
    }

    /// When the page group is DeviceCMYK, route a DeviceGray-derived image
    /// (DeviceGray itself, or Separation/DeviceN whose alt is DeviceGray)
    /// through the K plate so it composites equivalently to a DeviceCMYK
    /// 0/0/0/(1−g) image. Without this, GWG 23.0's "4 different Grays" test
    /// shows the right half of an X over its DeviceCMYK BG (left half comes
    /// from the polygon overpaint, fixed by `cmyk_group_promote_color`).
    ///
    /// Returns `(color_space, sample_data)` with the alt promoted to
    /// DeviceCMYK. For DeviceGray images we expand 1-byte gray samples to
    /// 4-byte CMYK with K=255−g; for Separation/DeviceN with DeviceGray alt
    /// we rebuild the tint table to emit `(0, 0, 0, 1−g)` instead of `g`.
    fn cmyk_group_promote_image(
        &self,
        cs: ImageColorSpace,
        data: Vec<u8>,
        width: u32,
        height: u32,
    ) -> (ImageColorSpace, Vec<u8>) {
        if !self.pdfx_cmyk_intent || self.in_smask_form {
            return (cs, data);
        }
        match cs {
            ImageColorSpace::DeviceGray => {
                let npx = (width as usize) * (height as usize);
                let take = npx.min(data.len());
                let mut new_data = vec![0u8; npx * 4];
                for i in 0..take {
                    new_data[i * 4 + 3] = 255 - data[i];
                }
                (ImageColorSpace::DeviceCMYK, new_data)
            }
            ImageColorSpace::Separation {
                name,
                alt_space,
                tint_table,
            } => {
                if matches!(alt_space.as_ref(), ImageColorSpace::DeviceGray)
                    && tint_table.num_outputs == 1
                {
                    let samples = tint_table.samples_per_dim as usize;
                    let mut new_data = Vec::with_capacity(samples * 4);
                    for i in 0..samples {
                        let g = tint_table.data[i] as f64;
                        let k = (1.0 - g).clamp(0.0, 1.0) as f32;
                        new_data.push(0.0);
                        new_data.push(0.0);
                        new_data.push(0.0);
                        new_data.push(k);
                    }
                    let promoted_table = TintLookupTable {
                        num_inputs: 1,
                        num_outputs: 4,
                        samples_per_dim: tint_table.samples_per_dim,
                        data: new_data,
                    };
                    (
                        ImageColorSpace::Separation {
                            name,
                            alt_space: Box::new(ImageColorSpace::DeviceCMYK),
                            tint_table: Arc::new(promoted_table),
                        },
                        data,
                    )
                } else {
                    (
                        ImageColorSpace::Separation {
                            name,
                            alt_space,
                            tint_table,
                        },
                        data,
                    )
                }
            }
            ImageColorSpace::DeviceN {
                names,
                alt_space,
                tint_table,
            } => {
                if matches!(alt_space.as_ref(), ImageColorSpace::DeviceGray)
                    && tint_table.num_outputs == 1
                {
                    let total = tint_table.data.len();
                    let mut new_data = Vec::with_capacity(total * 4);
                    for &g in &tint_table.data {
                        let k = (1.0 - g as f64).clamp(0.0, 1.0) as f32;
                        new_data.push(0.0);
                        new_data.push(0.0);
                        new_data.push(0.0);
                        new_data.push(k);
                    }
                    let promoted_table = TintLookupTable {
                        num_inputs: tint_table.num_inputs,
                        num_outputs: 4,
                        samples_per_dim: tint_table.samples_per_dim,
                        data: new_data,
                    };
                    (
                        ImageColorSpace::DeviceN {
                            names,
                            alt_space: Box::new(ImageColorSpace::DeviceCMYK),
                            tint_table: Arc::new(promoted_table),
                        },
                        data,
                    )
                } else {
                    (
                        ImageColorSpace::DeviceN {
                            names,
                            alt_space,
                            tint_table,
                        },
                        data,
                    )
                }
            }
            other => (other, data),
        }
    }

    /// When the page group is DeviceCMYK, override a paint's RGB with the
    /// CMYK-ICC rendering of its `native_cmyk` whenever the source RGB is
    /// itself a flat gray and the CMYK is K-only — matches the PDF/X
    /// behaviour expected for Separation/DeviceN paints whose alternate space
    /// is DeviceGray (e.g. Separation /Black tinted via gray=1−tint).
    fn cmyk_group_promote_color(&mut self, color: &mut DeviceColor) {
        if !self.pdfx_cmyk_intent || self.in_smask_form {
            return;
        }
        let Some((c, m, y, k)) = color.native_cmyk else {
            return;
        };
        // Only fire for K-only CMYK whose r/g/b currently form a flat gray —
        // that's the DeviceGray-alt case. DeviceCMYK paints already have ICC-
        // converted RGB, so the override would be a no-op there; restricting
        // to flat-gray r/g/b avoids ever touching genuine colour paints.
        if !(c == 0.0 && m == 0.0 && y == 0.0) {
            return;
        }
        // Skip the all-zero CMYK case. It legitimately encodes "white" for a
        // DeviceCMYK 0/0/0/0 paint (where r/g/b is already 1/1/1, so the
        // override would be a no-op), but it also surfaces from the separation
        // handler's fallback for non-K process colorants like /All — there
        // `native_cmyk` is set to (0,0,0,0) even when the visual is the alt-
        // gray result (e.g. Separation /All at tint=1 → gray=0 → black text).
        // ICC-converting (0,0,0,0) would erase those paints to white.
        if k == 0.0 {
            return;
        }
        if (color.r - color.g).abs() > f64::EPSILON || (color.r - color.b).abs() > f64::EPSILON {
            return;
        }
        if let Some((r, g, b)) = self.icc_cache.convert_cmyk(0.0, 0.0, 0.0, k) {
            color.r = r;
            color.g = g;
            color.b = b;
        }
    }

    fn op_big_k(&mut self) -> Result<(), PdfError> {
        // K c m y k: set stroke color to CMYK
        let n = self.get_numbers(4)?;
        self.gstate.stroke_color =
            DeviceColor::from_cmyk_icc(n[0], n[1], n[2], n[3], &mut self.icc_cache);
        self.gstate.stroke_color_space = ColorSpaceRef::DeviceCMYK;
        self.gstate.stroke_painted_channels = stet_graphics::device::CMYK_ALL;
        self.gstate.stroke_is_device_cmyk = true;
        self.gstate.stroke_is_none = false;
        self.gstate.stroke_spot_color = None;
        self.gstate.stroke_icc_color = None;
        self.gstate.stroke_pattern = None;
        self.gstate.stroke_shading_pattern = None;
        Ok(())
    }

    fn op_small_k(&mut self) -> Result<(), PdfError> {
        // k c m y k: set fill color to CMYK
        let n = self.get_numbers(4)?;
        self.gstate.fill_color =
            DeviceColor::from_cmyk_icc(n[0], n[1], n[2], n[3], &mut self.icc_cache);
        self.gstate.fill_color_space = ColorSpaceRef::DeviceCMYK;
        self.gstate.fill_painted_channels = stet_graphics::device::CMYK_ALL;
        self.gstate.fill_is_device_cmyk = true;
        self.gstate.fill_is_none = false;
        self.gstate.fill_spot_color = None;
        self.gstate.fill_icc_color = None;
        self.gstate.fill_pattern = None;
        self.gstate.fill_shading_pattern = None;
        Ok(())
    }

    // === General color operators ===

    fn op_big_cs(&mut self) -> Result<(), PdfError> {
        // CS name: set stroke color space
        let name = self
            .operand_stack
            .last()
            .and_then(|o| o.as_name())
            .ok_or(PdfError::Other("CS: expected name".into()))?
            .to_vec();
        self.gstate.stroke_color_space = name_to_cs_ref(&name);
        Ok(())
    }

    fn op_small_cs(&mut self) -> Result<(), PdfError> {
        // cs name: set fill color space
        let name = self
            .operand_stack
            .last()
            .and_then(|o| o.as_name())
            .ok_or(PdfError::Other("cs: expected name".into()))?
            .to_vec();
        self.gstate.fill_color_space = name_to_cs_ref(&name);
        Ok(())
    }

    /// Resolve a color space from a ColorSpaceRef.
    /// For named color spaces, uses a HashMap index of the ColorSpace resource
    /// sub-dict to avoid O(n) linear scans on large dicts (74K+ entries).
    fn resolve_cs_cached(
        &mut self,
        cs_ref: &ColorSpaceRef,
    ) -> Result<ResolvedColorSpace, PdfError> {
        if let ColorSpaceRef::Named(name) = cs_ref {
            // Fast path for device color space names
            match name.as_slice() {
                b"DeviceGray" | b"G" => return Ok(ResolvedColorSpace::DeviceGray),
                b"DeviceRGB" | b"RGB" => return Ok(ResolvedColorSpace::DeviceRGB),
                b"DeviceCMYK" | b"CMYK" => return Ok(ResolvedColorSpace::DeviceCMYK),
                b"Pattern" => return Ok(ResolvedColorSpace::Pattern),
                _ => {}
            }
            // Build HashMap index of ColorSpace resource dict on first use
            if self.cs_index.is_none() {
                let mut index = std::collections::HashMap::new();
                if let Some(cs_dict) = self.resolve_resource_subdict(b"ColorSpace") {
                    for (k, v) in cs_dict.entries() {
                        index.insert(k.clone(), v.clone());
                    }
                }
                self.cs_index = Some(index);
            }
            if let Some(cs_obj) = self.cs_index.as_ref().unwrap().get(name.as_slice()) {
                let cs_obj = cs_obj.clone();
                resolve_color_space_obj(&cs_obj, self.resolver)
            } else {
                // Name not in cached ColorSpace dict — fall back to full resolution
                // (handles resources without a ColorSpace sub-dict, or names that
                // appear due to resource inheritance not captured by the index)
                resolve_color_space(
                    &ColorSpaceRef::Named(name.to_vec()),
                    &self.resources,
                    self.resolver,
                )
            }
        } else {
            resolve_color_space(cs_ref, &self.resources, self.resolver)
        }
    }

    fn op_sc_stroke(&mut self) -> Result<(), PdfError> {
        // SC/SCN: set stroke color in current color space.
        // Some non-conforming PDFs use `/PatternName SCN` without first doing
        // `/Pattern CS` — detect a name operand and treat it as a pattern
        // reference regardless of the current color space.
        if matches!(self.operand_stack.last(), Some(Operand::Name(_))) {
            return self.handle_pattern_stroke();
        }
        let cs = self.resolve_cs_cached(&self.gstate.stroke_color_space.clone())?;
        if matches!(cs, ResolvedColorSpace::Pattern) {
            return self.handle_pattern_stroke();
        }
        let n = cs.num_components();
        if n == 0 {
            return Ok(());
        }
        let nums = self.get_numbers(n)?;
        self.gstate.stroke_painted_channels = painted_channels_for_cs(&cs);
        self.gstate.stroke_is_none = cs.is_none_colorant();
        self.gstate.stroke_is_device_cmyk = matches!(
            cs,
            ResolvedColorSpace::DeviceCMYK | ResolvedColorSpace::ICCBased { n: 4, .. }
        );
        let intent = self.gstate.rendering_intent;
        let mut color = color_space::components_to_device_color_icc_with_intent(
            &cs,
            &nums,
            Some(&mut self.icc_cache),
            intent,
        );
        self.cmyk_group_promote_color(&mut color);
        self.gstate.stroke_color = color;
        self.gstate.stroke_spot_color =
            color_space::build_spot_color(&cs, &nums, &mut self.spot_tint_table_cache);
        self.gstate.stroke_icc_color = color_space::build_icc_color(&cs, &nums);
        self.gstate.stroke_pattern = None;
        self.gstate.stroke_shading_pattern = None;
        Ok(())
    }

    fn op_sc_fill(&mut self) -> Result<(), PdfError> {
        // sc/scn: set fill color in current color space.
        // Some non-conforming PDFs use `/PatternName scn` without first doing
        // `/Pattern cs` — detect a name operand and treat it as a pattern
        // reference regardless of the current color space (matches hayro/Firefox).
        if matches!(self.operand_stack.last(), Some(Operand::Name(_))) {
            return self.handle_pattern_fill();
        }
        let cs = self.resolve_cs_cached(&self.gstate.fill_color_space.clone())?;
        if matches!(cs, ResolvedColorSpace::Pattern) {
            return self.handle_pattern_fill();
        }
        let n = cs.num_components();
        if n == 0 {
            return Ok(());
        }
        let nums = self.get_numbers(n)?;
        self.gstate.fill_painted_channels = painted_channels_for_cs(&cs);
        self.gstate.fill_is_none = cs.is_none_colorant();
        self.gstate.fill_is_device_cmyk = matches!(
            cs,
            ResolvedColorSpace::DeviceCMYK | ResolvedColorSpace::ICCBased { n: 4, .. }
        );
        let intent = self.gstate.rendering_intent;
        let mut color = color_space::components_to_device_color_icc_with_intent(
            &cs,
            &nums,
            Some(&mut self.icc_cache),
            intent,
        );
        self.cmyk_group_promote_color(&mut color);
        self.gstate.fill_color = color;
        self.gstate.fill_spot_color =
            color_space::build_spot_color(&cs, &nums, &mut self.spot_tint_table_cache);
        self.gstate.fill_icc_color = color_space::build_icc_color(&cs, &nums);
        self.gstate.fill_pattern = None;
        self.gstate.fill_shading_pattern = None;
        Ok(())
    }

    // === Text operators (state recording, Phase C will add rendering) ===

    fn op_tf(&mut self) -> Result<(), PdfError> {
        // Tf font size
        let len = self.operand_stack.len();
        if len < 2 {
            return Ok(());
        }
        self.gstate.font_size = self.operand_stack[len - 1].as_f64().unwrap_or(12.0);
        if let Some(name) = self.operand_stack[len - 2].as_name() {
            let name = name.to_vec();
            self.gstate.text_font_name = name.clone();
            self.resolve_current_font(&name);
        }
        Ok(())
    }

    /// Resolve the current font by name from the font cache or resources.
    fn resolve_current_font(&mut self, name: &[u8]) {
        // Check cache by name first (fast path for the common case where the
        // same name maps to the same font object across resource scopes).
        if let Some(cached) = self.font_cache.get(name) {
            // Verify the cached font still matches — different resource scopes
            // (page vs annotation vs form) may map the same name to different
            // font objects (e.g. /TT1 → obj 90 on page, /TT1 → obj 407 in annot).
            let font_ref = self
                .resolve_resource_subdict(b"Font")
                .and_then(|fd| fd.get(name).cloned());
            if let Some(PdfObj::Ref(obj_num, _)) = &font_ref {
                let obj_key = obj_num.to_le_bytes().to_vec();
                if let Some(obj_cached) = self.font_cache.get(&obj_key) {
                    // The obj-keyed cache has this font — use it (handles both
                    // same-as-name and different-from-name cases).
                    self.current_font = Some(Arc::clone(obj_cached));
                    return;
                }
                // obj key not in cache → this is a NEW font object that happens
                // to share a name with a previously cached font. Fall through to
                // resolve the new font instead of using the stale name-cached entry.
            } else {
                // No obj ref — use the name-cached font
                self.current_font = Some(Arc::clone(cached));
                return;
            }
        }

        // Cache miss — look up in resources /Font dict
        let font_ref = self
            .resolve_resource_subdict(b"Font")
            .and_then(|fd| fd.get(name).cloned());
        let font_ref = match font_ref {
            Some(r) => r,
            None => {
                // Font resource missing — try loading a default substitution font
                if let Some(fallback) = font::fallback_font(self.font_provider.as_ref()) {
                    let arc = Arc::new(fallback);
                    self.font_cache.insert(name.to_vec(), Arc::clone(&arc));
                    self.current_font = Some(arc);
                } else {
                    self.current_font = None;
                }
                return;
            }
        };

        // Check if this same object was already resolved under a different name
        if let PdfObj::Ref(obj_num, _) = &font_ref {
            let obj_key = obj_num.to_le_bytes().to_vec();
            if let Some(cached) = self.font_cache.get(&obj_key) {
                let arc = Arc::clone(cached);
                self.font_cache.insert(name.to_vec(), Arc::clone(&arc));
                self.current_font = Some(arc);
                return;
            }
        }

        match font::resolve_font(self.resolver, &font_ref, self.font_provider.as_ref()) {
            Ok(font) => {
                let arc = Arc::new(font);
                // Cache under both the name and object number keys
                if let PdfObj::Ref(obj_num, _) = &font_ref {
                    self.font_cache
                        .insert(obj_num.to_le_bytes().to_vec(), Arc::clone(&arc));
                }
                self.font_cache.insert(name.to_vec(), Arc::clone(&arc));
                self.current_font = Some(arc);
            }
            Err(e) => {
                // Deduplicate warnings across pages (same font fails on every page)
                use std::sync::Mutex;
                static WARNED: Mutex<Vec<String>> = Mutex::new(Vec::new());
                let msg = format!("font /{}: {}", String::from_utf8_lossy(name), e);
                if let Ok(mut set) = WARNED.lock()
                    && !set.contains(&msg)
                {
                    eprintln!("warning: {msg}");
                    set.push(msg);
                }
                // Try fallback font on resolution failure too
                if let Some(fallback) = font::fallback_font(self.font_provider.as_ref()) {
                    let arc = Arc::new(fallback);
                    self.font_cache.insert(name.to_vec(), Arc::clone(&arc));
                    self.current_font = Some(arc);
                } else {
                    self.current_font = None;
                }
            }
        }
    }

    /// Check if the current text position is outside the visible form area.
    /// If so, mark the BT block as culled to skip remaining text ops.
    fn check_text_cull(&mut self) {
        if let Some((y_lo, y_hi)) = self.form_cull_y {
            // Text Y in form coordinates is the ty component of the text matrix
            let text_y = self.gstate.text_matrix.ty;
            if text_y < y_lo || text_y > y_hi {
                self.bt_culled = true;
            }
        }
    }

    fn op_td(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(2)?;
        let m = Matrix::translate(n[0], n[1]);
        self.gstate.text_line_matrix = self.gstate.text_line_matrix.concat(&m);
        self.gstate.text_matrix = self.gstate.text_line_matrix;
        self.check_text_cull();
        Ok(())
    }

    fn op_big_td(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(2)?;
        self.gstate.text_leading = -n[1];
        let m = Matrix::translate(n[0], n[1]);
        self.gstate.text_line_matrix = self.gstate.text_line_matrix.concat(&m);
        self.gstate.text_matrix = self.gstate.text_line_matrix;
        self.check_text_cull();
        Ok(())
    }

    fn op_tm(&mut self) -> Result<(), PdfError> {
        let n = self.get_numbers(6)?;
        let m = Matrix::new(n[0], n[1], n[2], n[3], n[4], n[5]);
        self.gstate.text_matrix = m;
        self.gstate.text_line_matrix = m;
        self.check_text_cull();
        Ok(())
    }

    fn op_t_star(&mut self) -> Result<(), PdfError> {
        let leading = self.gstate.text_leading;
        let m = Matrix::translate(0.0, -leading);
        self.gstate.text_line_matrix = self.gstate.text_line_matrix.concat(&m);
        self.gstate.text_matrix = self.gstate.text_line_matrix;
        Ok(())
    }

    // === Text rendering operators ===

    fn op_tj(&mut self) -> Result<(), PdfError> {
        let text = match self.operand_stack.last() {
            Some(Operand::Str(s)) => s.clone(),
            _ => return Ok(()),
        };
        self.show_text(&text);
        Ok(())
    }

    fn op_big_tj(&mut self) -> Result<(), PdfError> {
        let arr = match self.operand_stack.last() {
            Some(Operand::Array(a)) => a.clone(),
            _ => return Ok(()),
        };
        let vertical = self.current_font.as_ref().is_some_and(|f| f.wmode() == 1);
        for elem in &arr {
            match elem {
                PdfObj::Str(s) => self.show_text(s),
                PdfObj::Int(n) => {
                    let shift = -*n as f64 / 1000.0 * self.gstate.font_size;
                    let m = if vertical {
                        Matrix::translate(0.0, shift)
                    } else {
                        Matrix::translate(shift * self.gstate.horizontal_scaling, 0.0)
                    };
                    self.gstate.text_matrix = self.gstate.text_matrix.concat(&m);
                }
                PdfObj::Real(f) => {
                    let shift = -f / 1000.0 * self.gstate.font_size;
                    let m = if vertical {
                        Matrix::translate(0.0, shift)
                    } else {
                        Matrix::translate(shift * self.gstate.horizontal_scaling, 0.0)
                    };
                    self.gstate.text_matrix = self.gstate.text_matrix.concat(&m);
                }
                _ => {}
            }
        }
        Ok(())
    }

    fn op_quote(&mut self) -> Result<(), PdfError> {
        // ': T* then Tj
        self.op_t_star()?;
        self.op_tj()
    }

    fn op_dblquote(&mut self) -> Result<(), PdfError> {
        // ": set word_spacing, char_spacing, then T* + Tj
        let len = self.operand_stack.len();
        if len < 3 {
            return Ok(());
        }
        self.gstate.word_spacing = self.operand_stack[len - 3].as_f64().unwrap_or(0.0);
        self.gstate.char_spacing = self.operand_stack[len - 2].as_f64().unwrap_or(0.0);
        // The string is at len-1, which op_tj reads from last()
        self.op_t_star()?;
        self.op_tj()
    }

    /// Render a text string by emitting glyph paths as Fill display elements.
    fn show_text(&mut self, text: &[u8]) {
        let font = match &self.current_font {
            Some(f) => Arc::clone(f),
            None => return,
        };

        let font_size = self.gstate.font_size;
        let char_spacing = self.gstate.char_spacing;
        let word_spacing = self.gstate.word_spacing;
        let text_rise = self.gstate.text_rise;
        let th = self.gstate.horizontal_scaling;
        let font_matrix = font.font_matrix();
        let render_mode = self.gstate.text_rendering_mode;

        if font.is_composite() {
            // Composite (CID) font: variable-width character codes
            // (most are 2-byte, but some CMaps define 1-byte codes for space etc.)
            let mut i = 0;
            while i < text.len() {
                let code_width = font.code_width(text[i]);
                if code_width == 1 {
                    // 1-byte code. Per PDF spec 9.3.3, word spacing applies to
                    // the single-byte character code 32 (SPACE) even in a
                    // composite font.
                    let raw_code = text[i] as u32;
                    let extra = if raw_code == 0x20 { word_spacing } else { 0.0 };
                    i += 1;
                    let cid = font.resolve_code_to_cid(raw_code) as u16;
                    self.render_cid_glyph(
                        &font,
                        cid,
                        font_size,
                        char_spacing,
                        th,
                        text_rise,
                        &font_matrix,
                        render_mode,
                        extra,
                    );
                } else if i + 1 >= text.len() {
                    // Incomplete trailing byte in 2-byte font — treat as WinAnsi
                    let byte = text[i];
                    i += 1;
                    self.render_unicode_glyph(
                        byte,
                        font_size,
                        char_spacing,
                        th,
                        text_rise,
                        &font_matrix,
                        render_mode,
                    );
                } else {
                    // Multi-byte code (2, 3, or 4 bytes from codespace ranges).
                    let width = code_width.min(text.len() - i);
                    let mut raw_code = 0u32;
                    for b in &text[i..i + width] {
                        raw_code = (raw_code << 8) | (*b as u32);
                    }
                    let cid = font.resolve_code_to_cid(raw_code) as u16;
                    // If the multi-byte code resolves to CID 0 (or the raw code
                    // itself for identity), the sequence may be invalid (e.g.
                    // UTF-8 continuation bytes out of range).  Try interpreting
                    // the first byte as a 1-byte code instead.
                    let (cid, consumed) = if cid == 0 || (cid == raw_code as u16 && width > 2) {
                        let byte_cid = font.resolve_code_to_cid(text[i] as u32) as u16;
                        if byte_cid != 0 && byte_cid != text[i] as u16 {
                            (byte_cid, 1)
                        } else {
                            (cid, width)
                        }
                    } else {
                        (cid, width)
                    };
                    // Word spacing applies only to SINGLE-byte code 32.
                    let extra = if consumed == 1 && text[i] == 0x20 {
                        word_spacing
                    } else {
                        0.0
                    };
                    i += consumed;
                    if font.has_cid_glyph(cid) {
                        // CID maps to a valid GID in the font
                        self.render_cid_glyph(
                            &font,
                            cid,
                            font_size,
                            char_spacing,
                            th,
                            text_rise,
                            &font_matrix,
                            render_mode,
                            extra,
                        );
                    } else {
                        // 2-byte CID has no glyph.  Some malformed PDFs encode
                        // single-byte CIDs in 2-byte Identity-H strings with a
                        // padding high byte (e.g. 0x20).  Try the low byte alone.
                        let lo_cid = (raw_code & 0xFF) as u16;
                        if lo_cid > 0 && font.has_cid_glyph(lo_cid) {
                            self.render_cid_glyph(
                                &font,
                                lo_cid,
                                font_size,
                                char_spacing,
                                th,
                                text_rise,
                                &font_matrix,
                                render_mode,
                                extra,
                            );
                        } else if raw_code <= 0xFF {
                            // Low code point with no CID glyph — malformed PDF mixing
                            // 1-byte WinAnsi text in a CID font.  Bypass the CID
                            // machinery and map each byte through WinAnsi→Unicode→cmap.
                            self.render_unicode_glyph(
                                text[i - 2],
                                font_size,
                                char_spacing,
                                th,
                                text_rise,
                                &font_matrix,
                                render_mode,
                            );
                            self.render_unicode_glyph(
                                text[i - 1],
                                font_size,
                                char_spacing,
                                th,
                                text_rise,
                                &font_matrix,
                                render_mode,
                            );
                        } else {
                            // CID glyph not available (e.g. substitute font for CJK).
                            // Use CID width for correct advancement; try Unicode for shape.
                            self.render_cid_glyph_unicode_fallback(
                                &font,
                                cid,
                                raw_code,
                                font_size,
                                char_spacing,
                                th,
                                text_rise,
                                &font_matrix,
                                render_mode,
                                extra,
                            );
                        }
                    }
                }
            }
        } else if font.is_type3() {
            // Type 3 font: each glyph is a content stream.
            // Widths are in glyph space — scale by font matrix to get text space.
            let fm = font.font_matrix();
            let visible = (render_mode & 3) != 3; // mode 3 = invisible
            for &byte in text {
                if visible {
                    self.show_type3_glyph(&font, byte);
                }

                let w0_glyph = font.glyph_width(byte);
                let w0 = w0_glyph * fm.a;
                let mut tx = w0 * font_size + char_spacing;
                if byte == b' ' {
                    tx += word_spacing;
                }
                tx *= th;
                let advance = Matrix::translate(tx, 0.0);
                self.gstate.text_matrix = self.gstate.text_matrix.concat(&advance);
            }
        } else {
            // Simple font: 1-byte character codes
            for &byte in text {
                if let Some(glyph_path) = font.glyph_path(byte) {
                    let text_state_matrix =
                        Matrix::new(font_size * th, 0.0, 0.0, font_size, 0.0, text_rise);
                    let trm = self
                        .gstate
                        .ctm
                        .concat(&self.gstate.text_matrix)
                        .concat(&text_state_matrix)
                        .concat(&font_matrix);

                    let device_path = glyph_path.transform(&trm);
                    if !device_path.is_empty() {
                        self.emit_text_glyph(device_path, render_mode);
                    }
                }

                let w0 = font.glyph_width(byte);
                let mut tx = w0 * font_size + char_spacing;
                if byte == b' ' {
                    tx += word_spacing;
                }
                tx *= th;
                let advance = Matrix::translate(tx, 0.0);
                self.gstate.text_matrix = self.gstate.text_matrix.concat(&advance);
            }
        }
    }

    /// Render a single CID glyph and advance the text position.
    fn render_cid_glyph(
        &mut self,
        font: &PdfFont,
        cid: u16,
        font_size: f64,
        char_spacing: f64,
        th: f64,
        text_rise: f64,
        font_matrix: &Matrix,
        render_mode: i32,
        extra_advance: f64,
    ) {
        let vertical = font.wmode() == 1;
        if let Some(glyph_path) = font.glyph_path_cid(cid) {
            let text_state_matrix = if vertical {
                // Vertical mode: use per-CID metrics (w1, v_x, v_y) from W2/DW2.
                // v_x/v_y define the position vector from horizontal to vertical origin.
                let [_w1, v_x, v_y] = font.vertical_metrics_cid(cid);
                Matrix::new(
                    font_size,
                    0.0,
                    0.0,
                    font_size,
                    -v_x / 1000.0 * font_size,
                    -v_y / 1000.0 * font_size,
                )
            } else {
                Matrix::new(font_size * th, 0.0, 0.0, font_size, 0.0, text_rise)
            };
            let trm = self
                .gstate
                .ctm
                .concat(&self.gstate.text_matrix)
                .concat(&text_state_matrix)
                .concat(font_matrix);
            let device_path = glyph_path.transform(&trm);
            if !device_path.is_empty() {
                self.emit_text_glyph(device_path, render_mode);
            }
        }
        if vertical {
            let [w1, _vx, _vy] = font.vertical_metrics_cid(cid);
            let ty = w1 / 1000.0 * font_size + char_spacing + extra_advance;
            let advance = Matrix::translate(0.0, ty);
            self.gstate.text_matrix = self.gstate.text_matrix.concat(&advance);
        } else {
            let w0 = font.glyph_width_cid(cid);
            let tx = (w0 * font_size + char_spacing + extra_advance) * th;
            let advance = Matrix::translate(tx, 0.0);
            self.gstate.text_matrix = self.gstate.text_matrix.concat(&advance);
        }
    }

    /// Render a CID glyph using Unicode→cmap for the glyph shape but the CID
    /// width table for text advancement. Used for substitute fonts that don't
    /// have CID-to-GID mappings but can render via Unicode code points.
    fn render_cid_glyph_unicode_fallback(
        &mut self,
        font: &PdfFont,
        cid: u16,
        unicode: u32,
        font_size: f64,
        char_spacing: f64,
        th: f64,
        text_rise: f64,
        font_matrix: &Matrix,
        render_mode: i32,
        extra_advance: f64,
    ) {
        let vertical = font.wmode() == 1;
        // Try to render the glyph shape via Unicode mapping in the substitute font
        if let Some(glyph_path) = font.glyph_path_unicode(unicode as u16) {
            let text_state_matrix = if vertical {
                let [_w1, v_x, v_y] = font.vertical_metrics_cid(cid);
                Matrix::new(
                    font_size,
                    0.0,
                    0.0,
                    font_size,
                    -v_x / 1000.0 * font_size,
                    -v_y / 1000.0 * font_size,
                )
            } else {
                Matrix::new(font_size * th, 0.0, 0.0, font_size, 0.0, text_rise)
            };
            let trm = self
                .gstate
                .ctm
                .concat(&self.gstate.text_matrix)
                .concat(&text_state_matrix)
                .concat(font_matrix);
            let device_path = glyph_path.transform(&trm);
            if !device_path.is_empty() {
                self.emit_text_glyph(device_path, render_mode);
            }
        }
        if vertical {
            let [w1, _vx, _vy] = font.vertical_metrics_cid(cid);
            let ty = w1 / 1000.0 * font_size + char_spacing + extra_advance;
            let advance = Matrix::translate(0.0, ty);
            self.gstate.text_matrix = self.gstate.text_matrix.concat(&advance);
        } else {
            let w0 = font.glyph_width_cid(cid);
            let tx = (w0 * font_size + char_spacing + extra_advance) * th;
            let advance = Matrix::translate(tx, 0.0);
            self.gstate.text_matrix = self.gstate.text_matrix.concat(&advance);
        }
    }

    /// Render a single glyph from a WinAnsi byte via Unicode→cmap, bypassing CID.
    /// Used for malformed PDFs that embed 1-byte literal strings in CID fonts.
    fn render_unicode_glyph(
        &mut self,
        byte: u8,
        font_size: f64,
        char_spacing: f64,
        th: f64,
        text_rise: f64,
        font_matrix: &Matrix,
        render_mode: i32,
    ) {
        let unicode = font::winansi_byte_to_unicode(byte);
        if let Some(glyph_path) = self
            .current_font
            .as_ref()
            .and_then(|f| f.glyph_path_unicode(unicode))
        {
            let text_state_matrix =
                Matrix::new(font_size * th, 0.0, 0.0, font_size, 0.0, text_rise);
            let trm = self
                .gstate
                .ctm
                .concat(&self.gstate.text_matrix)
                .concat(&text_state_matrix)
                .concat(font_matrix);
            let device_path = glyph_path.transform(&trm);
            if !device_path.is_empty() {
                self.emit_text_glyph(device_path, render_mode);
            }
        }
        let w0 = self
            .current_font
            .as_ref()
            .map(|f| f.glyph_width_unicode(unicode))
            .unwrap_or(0.0);
        let tx = (w0 * font_size + char_spacing) * th;
        let advance = Matrix::translate(tx, 0.0);
        self.gstate.text_matrix = self.gstate.text_matrix.concat(&advance);
    }

    /// Render a single Type 3 glyph by interpreting its CharProc content stream.
    fn show_type3_glyph(&mut self, font: &PdfFont, char_code: u8) {
        let proc_data = match font.type3_char_proc(char_code) {
            Some(data) => data.to_vec(),
            None => return,
        };
        let resources = match font.type3_resources() {
            Some(r) => r.clone(),
            None => return,
        };

        let font_size = self.gstate.font_size;
        let text_rise = self.gstate.text_rise;
        let font_matrix = font.font_matrix();

        // Build the text rendering matrix: CTM × Tm × [fontSize*Th 0 0 fontSize 0 rise] × FontMatrix
        let th = self.gstate.horizontal_scaling;
        let text_state_matrix = Matrix::new(font_size * th, 0.0, 0.0, font_size, 0.0, text_rise);
        let trm = self
            .gstate
            .ctm
            .concat(&self.gstate.text_matrix)
            .concat(&text_state_matrix)
            .concat(&font_matrix);
        // Interpret the CharProc stream with TRM as the CTM.
        // Save current state and swap in a fresh display list.
        let stack_depth_before = self.gstate_stack.len();
        self.gstate_stack.push(self.gstate.clone());
        // Merge the Type 3 font's resources with the page resources: the font's
        // own entries take priority (e.g. XObjects for emoji glyphs), but missing
        // categories fall back to the page resources (e.g. fonts referenced by
        // CharProcs that don't declare their own /Font sub-dict).
        let mut merged = self.resources.clone();
        for (key, value) in resources.entries() {
            merged.insert(key.clone(), value.clone());
        }
        let saved_resources = std::mem::replace(&mut self.resources, merged);
        let saved_display_list = std::mem::take(&mut self.display_list);
        let saved_path = std::mem::take(&mut self.current_path);
        let saved_point = self.current_point.take();
        let saved_subpath = self.subpath_start.take();
        let saved_font = self.current_font.clone();
        let saved_in_text = self.in_text;
        let saved_content_stream_ctm = self.content_stream_ctm;
        let saved_mc_stack = std::mem::take(&mut self.mc_stack);

        self.gstate.ctm = trm;
        // Pattern Matrix maps pattern space to the "default coordinate system
        // of the content stream" — for Type 3 CharProcs, that's the TRM.
        self.content_stream_ctm = trm;

        let saved_d1 = self.d1_color_suppressed;
        self.d1_color_suppressed = false;
        self.depth += 1;
        let _ = self.interpret_stream(&proc_data);
        self.depth -= 1;
        self.d1_color_suppressed = saved_d1;
        // Collect glyph display elements and append to main display list
        let glyph_elements = std::mem::replace(&mut self.display_list, saved_display_list);
        self.resources = saved_resources;
        self.current_path = saved_path;
        self.current_point = saved_point;
        self.subpath_start = saved_subpath;
        self.current_font = saved_font;
        self.in_text = saved_in_text;
        self.content_stream_ctm = saved_content_stream_ctm;
        self.mc_stack = saved_mc_stack;
        // Restore state: truncate any extra gstate_stack entries left by
        // unmatched q/Q inside the CharProc (e.g., if the EI parser consumed Q).
        self.gstate_stack.truncate(stack_depth_before + 1);
        if let Some(saved) = self.gstate_stack.pop() {
            self.gstate = saved;
        }

        // Append all glyph elements to the main display list
        for elem in glyph_elements.into_elements() {
            self.display_list.push(elem);
        }
    }

    /// Emit a text glyph to the display list based on the text rendering mode.
    ///
    /// Modes: 0=fill, 1=stroke, 2=fill+stroke, 3=invisible,
    ///        4-7=same as 0-3 but add to clipping path (clipping not yet implemented).
    fn emit_text_glyph(&mut self, device_path: PsPath, render_mode: i32) {
        let mode = render_mode & 3; // strip clip bit
        let clip = render_mode & 4 != 0; // bit 2 = add to text clip

        match mode {
            0 => {
                // Fill only
                self.emit_text_fill(device_path.clone());
            }
            1 => {
                // Stroke only
                self.emit_text_stroke(device_path.clone());
            }
            2 => {
                // Fill then stroke
                self.emit_text_fill(device_path.clone());
                self.emit_text_stroke(device_path.clone());
            }
            _ => {} // mode 3 = invisible
        }

        // Modes 4-7: accumulate glyph path into text clip
        if clip {
            let tcp = self.text_clip_path.get_or_insert_with(PsPath::new);
            tcp.segments.extend_from_slice(&device_path.segments);
        }
    }

    /// Emit a text glyph fill, handling shading patterns, tiling patterns,
    /// or solid color fills.
    fn emit_text_fill(&mut self, path: PsPath) {
        if let Some(shading_box) = self.gstate.fill_shading_pattern.clone() {
            // PatternType 2 (shading pattern): clip to glyph path, emit shading.
            // Wrap in a Group to scope the clip.
            let bbox = path_device_bbox(&path);
            let mut group_dl = DisplayList::new();
            group_dl.push(DisplayElement::Clip {
                path,
                params: ClipParams {
                    fill_rule: FillRule::NonZeroWinding,
                    ctm: Matrix::identity(),
                    stroke_params: None,
                },
            });
            for elem in shading_box.0.elements() {
                group_dl.push(elem.clone());
            }
            self.display_list.push(DisplayElement::Group {
                elements: group_dl,
                params: GroupParams {
                    bbox,
                    isolated: true,
                    knockout: false,
                    blend_mode: self.gstate.blend_mode,
                    alpha: self.gstate.fill_alpha,
                    color_space: stet_graphics::display_list::GroupColorSpace::Inherited,
                },
            });
        } else if let Some(pattern) = self.gstate.fill_pattern.clone() {
            self.display_list.push(DisplayElement::PatternFill {
                params: PatternFillParams {
                    path,
                    fill_rule: FillRule::NonZeroWinding,
                    tile: pattern.tile,
                    pattern_matrix: pattern.pattern_matrix,
                    bbox: pattern.bbox,
                    xstep: pattern.x_step,
                    ystep: pattern.y_step,
                    paint_type: pattern.paint_type,
                    underlying_color: if pattern.paint_type == 2 {
                        Some(self.gstate.fill_color.clone())
                    } else {
                        None
                    },
                    pattern_id: pattern.pattern_id,
                    device_space_tile: false,
                    flip_tile_y: false,
                    stroke_params: None,
                    overprint_mode: if self.gstate.overprint {
                        self.gstate.overprint_mode
                    } else {
                        0
                    },
                },
            });
        } else {
            let mut params = self.gstate.fill_params(FillRule::NonZeroWinding);
            params.is_text_glyph = true;
            self.display_list
                .push(DisplayElement::Fill { path, params });
        }
    }

    /// Emit a text glyph stroke, handling shading patterns, tiling patterns,
    /// or solid color strokes.
    fn emit_text_stroke(&mut self, path: PsPath) {
        // Shading pattern stroke: clip to stroked outline of glyph, emit shading.
        if let Some(shading_box) = self.gstate.stroke_shading_pattern.clone() {
            let mut sp = self.gstate.stroke_params();
            sp.is_text_glyph = true;
            // Expand bbox by half the (already device-scaled) stroke width.
            let mut bbox = path_device_bbox(&path);
            let half_w = sp.line_width * 0.5;
            bbox[0] -= half_w;
            bbox[1] -= half_w;
            bbox[2] += half_w;
            bbox[3] += half_w;
            let mut group_dl = DisplayList::new();
            group_dl.push(DisplayElement::Clip {
                path,
                params: ClipParams {
                    fill_rule: FillRule::NonZeroWinding,
                    ctm: Matrix::identity(),
                    stroke_params: Some(sp),
                },
            });
            for elem in shading_box.0.elements() {
                group_dl.push(elem.clone());
            }
            self.display_list.push(DisplayElement::Group {
                elements: group_dl,
                params: GroupParams {
                    bbox,
                    isolated: true,
                    knockout: false,
                    blend_mode: self.gstate.blend_mode,
                    alpha: self.gstate.stroke_alpha,
                    color_space: stet_graphics::display_list::GroupColorSpace::Inherited,
                },
            });
            return;
        }

        // Tiling pattern stroke: emit PatternFill with stroke_params so the
        // renderer tiles the pattern over the stroked outline of the glyph.
        if let Some(pattern) = self.gstate.stroke_pattern.clone() {
            let mut sp = self.gstate.stroke_params();
            sp.is_text_glyph = true;
            self.display_list.push(DisplayElement::PatternFill {
                params: PatternFillParams {
                    path,
                    fill_rule: FillRule::NonZeroWinding,
                    tile: pattern.tile,
                    pattern_matrix: pattern.pattern_matrix,
                    bbox: pattern.bbox,
                    xstep: pattern.x_step,
                    ystep: pattern.y_step,
                    paint_type: pattern.paint_type,
                    underlying_color: if pattern.paint_type == 2 {
                        Some(self.gstate.stroke_color.clone())
                    } else {
                        None
                    },
                    pattern_id: pattern.pattern_id,
                    device_space_tile: false,
                    flip_tile_y: false,
                    stroke_params: Some(sp),
                    overprint_mode: if self.gstate.overprint {
                        self.gstate.overprint_mode
                    } else {
                        0
                    },
                },
            });
            return;
        }

        let mut params = self.gstate.stroke_params();
        params.is_text_glyph = true;
        self.display_list
            .push(DisplayElement::Stroke { path, params });
    }

    // === Marked content operators ===

    /// Handle BDC (begin marked content with properties). Checks for Optional
    /// Content Group references and wraps content inside OCG blocks in an
    /// `OcgGroup` display list element for deferred visibility filtering at
    /// render time. Every BDC pushes a frame onto `mc_stack` — only `/OC`
    /// BDCs are `Ocg` frames; other BDCs are `Other` placeholders so the
    /// stack stays balanced with EMC.
    fn op_bdc(&mut self) -> Result<(), PdfError> {
        let props = self.operand_stack.pop();
        let tag = self.operand_stack.pop();

        let is_oc = matches!(&tag, Some(Operand::Name(n)) if n == b"OC");
        if !is_oc {
            self.mc_stack.push(MarkedContentFrame::Other);
            return Ok(());
        }

        // The properties operand is a name referencing /Properties in resources
        let mut pushed = false;
        if let Some(Operand::Name(prop_name)) = props
            && let Some(props_dict) = self.resolve_resource_subdict(b"Properties")
            && let Some(ocg_obj) = props_dict.get(&prop_name)
        {
            let visibility = self.build_visibility(ocg_obj);
            let parent_list = std::mem::replace(&mut self.display_list, DisplayList::new());
            self.mc_stack.push(MarkedContentFrame::Ocg {
                parent_list,
                visibility,
            });
            pushed = true;
        }
        if !pushed {
            // OC BDC without a resolvable properties entry still opens a
            // section that EMC must close.
            self.mc_stack.push(MarkedContentFrame::Other);
        }

        Ok(())
    }

    /// Check whether an OCG/OCMD reference is OFF.
    /// Handles both direct OCG references (`/Type /OCG`) and OCMD wrappers
    /// (`/Type /OCMD` with `/OCGs` array and optional `/P` visibility policy).
    fn is_ocg_off(&self, ocg_obj: &PdfObj) -> bool {
        // Direct OCG reference — check its object number
        if let Some((obj_num, _)) = ocg_obj.as_ref() {
            // Dereference to see if it's an OCMD wrapper
            if let Ok(resolved) = self.resolver.deref(ocg_obj) {
                if let Some(dict) = resolved.as_dict() {
                    if dict.get_name(b"Type") == Some(b"OCMD") {
                        return self.is_ocmd_off(dict);
                    }
                }
            }
            // Plain OCG reference
            return self.ocg_off.contains(&obj_num);
        }
        // Inline dict (unusual but possible)
        if let Some(dict) = ocg_obj.as_dict() {
            if dict.get_name(b"Type") == Some(b"OCMD") {
                return self.is_ocmd_off(dict);
            }
        }
        false
    }

    /// Build an [`OcgVisibility`] from an `/OC BDC` properties reference
    /// or an XObject `/OC` entry.
    ///
    /// - Direct OCG ref → [`OcgVisibility::Single`] driven by
    ///   `/OCProperties /D /OFF` membership.
    /// - OCMD with `/VE` → [`OcgVisibility::Expression`].
    /// - OCMD with `/OCGs` (and optional `/P`) →
    ///   [`OcgVisibility::Membership`] with the parsed policy.
    /// - Unparseable shape → `Single { ocg_id: 0, default_visible:
    ///   <baked> }` so the renderer falls back to the document's
    ///   static evaluation.
    fn build_visibility(&self, ocg_obj: &PdfObj) -> OcgVisibility {
        let resolved = self.resolver.deref(ocg_obj).ok();
        let dict = resolved.as_ref().and_then(|o| o.as_dict());

        if let Some(dict) = dict
            && dict.get_name(b"Type") == Some(b"OCMD")
        {
            // Default-visible for the whole OCMD = its static
            // evaluation under the document's default config. Acts as
            // the fast-path return value of `LayerSet::evaluate` when
            // no leaf has been overridden.
            let default_visible = !self.is_ocg_off(ocg_obj);
            // OCMD parsing produces Membership or Expression. We
            // don't have a `WarningSink` plumbed through the content
            // stream pipeline yet, so route warnings into a local
            // throwaway sink — `/VE` malformations are infrequent and
            // already fall back to AnyOn membership.
            let throwaway = crate::diagnostics::WarningSink::new();
            return crate::layers::ocmd::build_ocmd_visibility(
                self.resolver,
                dict,
                default_visible,
                &throwaway,
            );
        }

        if let Some((ocg_id, _)) = ocg_obj.as_ref() {
            return OcgVisibility::Single {
                ocg_id,
                default_visible: !self.ocg_off.contains(&ocg_id),
            };
        }

        // Inline OCG dict or other unparseable shape.
        OcgVisibility::Single {
            ocg_id: 0,
            default_visible: !self.is_ocg_off(ocg_obj),
        }
    }

    /// Evaluate an OCMD (Optional Content Membership Dictionary).
    /// `/P` policy: AnyOn (default) = visible if ANY listed OCG is on;
    /// AnyOff = visible if ANY is off; AllOn = visible if ALL are on;
    /// AllOff = visible if ALL are off.
    fn is_ocmd_off(&self, ocmd: &PdfDict) -> bool {
        let policy = ocmd.get_name(b"P").unwrap_or(b"AnyOn");

        // Collect OCG object numbers from /OCGs (may be a single ref or array)
        let mut ocg_nums = Vec::new();
        if let Some(ocgs_obj) = ocmd.get(b"OCGs") {
            match ocgs_obj {
                PdfObj::Ref(num, _) => ocg_nums.push(*num),
                PdfObj::Array(arr) => {
                    for item in arr {
                        if let Some((num, _)) = item.as_ref() {
                            ocg_nums.push(num);
                        }
                    }
                }
                _ => {}
            }
        }
        if ocg_nums.is_empty() {
            return false;
        }

        // Evaluate visibility based on policy, then return whether suppressed
        let visible = match policy {
            b"AllOn" => ocg_nums.iter().all(|n| !self.ocg_off.contains(n)),
            b"AnyOff" => ocg_nums.iter().any(|n| self.ocg_off.contains(n)),
            b"AllOff" => ocg_nums.iter().all(|n| self.ocg_off.contains(n)),
            _ /* AnyOn */ => ocg_nums.iter().any(|n| !self.ocg_off.contains(n)),
        };
        !visible
    }

    // === XObject operator ===

    fn op_do(&mut self) -> Result<(), PdfError> {
        let name = self
            .operand_stack
            .last()
            .and_then(|o| o.as_name())
            .ok_or(PdfError::Other("Do: expected name".into()))?
            .to_vec();

        // Look up XObject in resources (may be an indirect reference)
        let xobj_dict = self
            .resolve_resource_subdict(b"XObject")
            .ok_or(PdfError::Other("no XObject resources".into()))?;
        let xobj_ref = xobj_dict.get(&name).ok_or_else(|| {
            PdfError::Other(format!(
                "XObject /{} not found",
                String::from_utf8_lossy(&name)
            ))
        })?;
        // Keep the original ref for stream_data_from_obj (needed for encryption)
        let xobj_ref_clone = xobj_ref.clone();
        let xobj = self.resolver.deref(xobj_ref)?;
        let dict = xobj
            .as_dict()
            .ok_or(PdfError::Other("XObject is not a stream".into()))?;

        // Check Optional Content visibility on the XObject itself.
        // Instead of suppressing content, wrap it in an OcgGroup so visibility
        // can be toggled at render time.
        let xobj_visibility = dict.get(b"OC").map(|oc_obj| self.build_visibility(oc_obj));

        let mut wrapped = false;
        if let Some(visibility) = xobj_visibility {
            let parent_list = std::mem::replace(&mut self.display_list, DisplayList::new());
            self.mc_stack.push(MarkedContentFrame::Ocg {
                parent_list,
                visibility,
            });
            wrapped = true;
        }

        let subtype = dict.get_name(b"Subtype").unwrap_or(b"");
        match subtype {
            b"Image" => self.handle_image_xobject(&xobj_ref_clone, dict)?,
            b"Form" => self.handle_form_xobject(&xobj_ref_clone, dict)?,
            _ => {}
        }

        // Close the XObject OCG wrapper if one was opened.
        if wrapped {
            if let Some(MarkedContentFrame::Ocg {
                parent_list,
                visibility,
            }) = self.mc_stack.pop()
            {
                let ocg_list = std::mem::replace(&mut self.display_list, parent_list);
                self.display_list.push(DisplayElement::OcgGroup {
                    elements: ocg_list,
                    visibility,
                });
            }
        }

        Ok(())
    }

    /// Handle an Image XObject.
    fn handle_image_xobject(&mut self, obj: &PdfObj, dict: &PdfDict) -> Result<(), PdfError> {
        // Check image cache: if we've already processed this XObject, reuse the
        // decoded data with fresh graphics-state params (CTM, alpha, blend, etc.).
        if let PdfObj::Ref(obj_num, _) = obj {
            if let Some(cached) = self.image_cache.get(obj_num).cloned() {
                return self.emit_cached_image(cached);
            }
        }

        // Width/Height may be indirect references in some PDFs
        let width = self
            .resolve_dict_int(dict, b"Width")
            .ok_or(PdfError::Other("image missing Width".into()))? as u32;
        let height = self
            .resolve_dict_int(dict, b"Height")
            .ok_or(PdfError::Other("image missing Height".into()))? as u32;

        // Check for image mask (1-bit stencil painted with current fill color)
        let is_image_mask = dict
            .get(b"ImageMask")
            .and_then(|o| match o {
                PdfObj::Bool(b) => Some(*b),
                _ => None,
            })
            .unwrap_or(false);

        let bpc = if is_image_mask {
            1
        } else {
            dict.get_int(b"BitsPerComponent").unwrap_or(8) as u32
        };

        // Per ISO 32000 §11.3.4 a per-image `/Intent` overrides the gstate
        // `/RI`. GWG 17.2 (JPEG2000 + ICCBasedRGB) calibrates an Adobe RGB
        // image colour against a CMYK swatch under `/RelativeColorimetric`;
        // ignoring this override forces the proofing chain through the
        // gstate's default Perceptual intent and produces a visibly
        // different sRGB → the test's "X marker" appears.
        let gstate_intent = self.gstate.rendering_intent;
        let image_intent = match dict
            .get(b"Intent")
            .and_then(|o| self.resolver.deref(o).ok())
        {
            Some(PdfObj::Name(n)) => match n.as_slice() {
                b"Perceptual" => 0u8,
                b"RelativeColorimetric" => 1,
                b"Saturation" => 2,
                b"AbsoluteColorimetric" => 3,
                _ => gstate_intent,
            },
            _ => gstate_intent,
        };

        // Resolve color space
        let has_explicit_cs = dict.get(b"ColorSpace").is_some();
        let resolved_cs = if is_image_mask {
            None
        } else if let Some(cs_obj) = dict.get(b"ColorSpace") {
            match resolve_color_space_obj(cs_obj, self.resolver) {
                Ok(cs) => Some(cs),
                Err(_) => {
                    // Damaged PDF: color space reference is invalid (e.g. points to
                    // an XRef stream in a corrupt linearized file). Fall back to a
                    // device color space based on BPC/component count heuristics.
                    Some(match bpc {
                        1 => ResolvedColorSpace::DeviceGray,
                        _ => ResolvedColorSpace::DeviceRGB,
                    })
                }
            }
        } else {
            // No ColorSpace in dict — will be inferred from JPX data below
            Some(ResolvedColorSpace::DeviceRGB)
        };

        let polarity = if is_image_mask {
            if let Some(arr) = dict.get_array(b"Decode") {
                let vals: Vec<f64> = arr.iter().filter_map(|o| o.as_f64()).collect();
                vals.len() >= 2 && vals[0] > 0.5
            } else {
                false
            }
        } else {
            false
        };

        // SMaskInData: JPX streams can embed an alpha channel.
        // 0 (default) = no embedded mask, 1 or 2 = alpha channel present in JP2 data.
        let smask_in_data = dict.get_int(b"SMaskInData").unwrap_or(0);

        let filter_name_raw = dict.get_name(b"Filter");
        let filter_is_dct = matches!(filter_name_raw, Some(b"DCTDecode" | b"DCT"));
        // JPXDecode may be a single filter name or inside a filter array
        let filter_is_jpx = matches!(filter_name_raw, Some(b"JPXDecode" | b"JPX"))
            || dict.get_array(b"Filter").is_some_and(|arr| {
                arr.iter()
                    .any(|f| matches!(f.as_name(), Some(b"JPXDecode" | b"JPX")))
            });

        // Decode the stream data. For DCTDecode with a bogus SOF height
        // (streaming encoder placeholder like 60000), patch the JPEG header
        // to the PDF dict height before decoding to avoid wasting time on
        // excess zero-filled rows.
        let cs_is_indexed = matches!(resolved_cs, Some(ResolvedColorSpace::Indexed { .. }));
        let sample_data = if filter_is_dct {
            if let Some(raw) = self.resolver.raw_stream_bytes(obj)
                && let Some((_jw, jh)) = crate::filters::jpeg_dimensions(raw)
                && jh > height * 2
            {
                let mut patched = raw.to_vec();
                crate::filters::patch_jpeg_sof_height(&mut patched, height as u16);
                crate::filters::decode_stream(
                    &patched,
                    &[crate::filters::Filter::DCTDecode],
                    &[],
                    None,
                )?
            } else {
                self.resolver.stream_data_from_obj(obj)?
            }
        } else if filter_is_jpx && cs_is_indexed {
            // JPXDecode + PDF Indexed color space: skip JP2-internal palette
            // resolution so the PDF's own lookup table handles depalettization.
            // Some JP2 files declare wrong palette column precision (e.g. 4-bit
            // for 8-bit values), causing hayro's palette expansion to corrupt colors.
            #[cfg(feature = "jpx")]
            {
                if let Some(raw) = self.resolver.raw_stream_bytes(obj) {
                    let jp2_data = crate::filters::decode_pre_jpx(raw, dict);
                    let (mut data, bpc) = crate::filters::decode_jpx_no_palette(&jp2_data)?;
                    // hayro normalizes sub-8-bit data to 0-255 grayscale.
                    // Un-normalize back to raw palette indices using the
                    // codestream's original bit depth.
                    if bpc < 8 {
                        let max_val = ((1u32 << bpc) - 1) as f64;
                        for b in data.iter_mut() {
                            *b = (*b as f64 / 255.0 * max_val).round() as u8;
                        }
                    }
                    data
                } else {
                    self.resolver.stream_data_from_obj(obj)?
                }
            }
            #[cfg(not(feature = "jpx"))]
            {
                self.resolver.stream_data_from_obj(obj)?
            }
        } else {
            self.resolver.stream_data_from_obj(obj)?
        };

        // For DCTDecode, the JPEG's actual dimensions may differ from the PDF
        // dict's /Width and /Height.  Trust the image header when they disagree,
        // but only when the JPEG dimensions are close to the PDF dict values.
        let (width, height) = if filter_is_dct {
            if let Some(raw) = self.resolver.raw_stream_bytes(obj)
                && let Some((jw, jh)) = crate::filters::jpeg_dimensions(raw)
                && (jw != width || jh != height)
                && jw <= width * 2
                && jh <= height * 2
            {
                (jw, jh)
            } else {
                (width, height)
            }
        } else if filter_is_jpx {
            #[cfg(feature = "jpx")]
            {
                // JPXDecode: the JPEG 2000 stream may have different dimensions
                // than the PDF dict (malformed but common). Decode the filter chain
                // up to but not including JPXDecode to get the raw JP2 data.
                if let Some(raw) = self.resolver.raw_stream_bytes(obj) {
                    // Apply preceding filters (e.g. ASCIIHexDecode) to get JP2 data
                    let jp2_data = crate::filters::decode_pre_jpx(raw, dict);
                    if let Some((jw, jh)) = crate::filters::jpx_dimensions(&jp2_data)
                        && (jw != width || jh != height)
                    {
                        (jw, jh)
                    } else {
                        (width, height)
                    }
                } else {
                    (width, height)
                }
            }
            #[cfg(not(feature = "jpx"))]
            {
                (width, height)
            }
        } else {
            (width, height)
        };

        // For JPXDecode, the JP2 decoder returns all components present in the
        // codestream, which may include alpha or other channels beyond what the
        // PDF's explicit ColorSpace expects. With SMaskInData >= 1 the extra
        // alpha component is exposed as a soft mask; with SMaskInData == 0
        // (default), per ISO 32000-2 §13.5.7.2 the encoded soft-mask information
        // shall be ignored — drop the extras so the gray/RGB/CMYK pipeline
        // doesn't reinterpret interleaved alpha bytes as image samples.
        // When no explicit ColorSpace is present, infer it from the decoded
        // data length.
        let (resolved_cs, sample_data, smask_in_data_alpha) =
            if !is_image_mask && filter_is_jpx && has_explicit_cs {
                let n_cs = resolved_cs
                    .as_ref()
                    .map_or(3, |cs| cs.num_components() as usize);
                let pixels = width as usize * height as usize;
                let decoded_comps = if pixels > 0 {
                    sample_data.len() / pixels
                } else {
                    n_cs
                };
                if smask_in_data >= 1 && decoded_comps == n_cs + 1 {
                    // Extract the alpha channel (last component per pixel)
                    let mut color_data = Vec::with_capacity(pixels * n_cs);
                    let mut alpha_data = Vec::with_capacity(pixels);
                    for chunk in sample_data.chunks_exact(decoded_comps) {
                        color_data.extend_from_slice(&chunk[..n_cs]);
                        alpha_data.push(chunk[n_cs]);
                    }
                    (resolved_cs, color_data, Some(alpha_data))
                } else if decoded_comps > n_cs {
                    // Drop extra components (e.g. ignored alpha) — keep only the
                    // first n_cs samples of each pixel.
                    let mut color_data = Vec::with_capacity(pixels * n_cs);
                    for chunk in sample_data.chunks_exact(decoded_comps) {
                        color_data.extend_from_slice(&chunk[..n_cs]);
                    }
                    (resolved_cs, color_data, None)
                } else {
                    // Component count matches (or is unexpectedly low) — pass through
                    (resolved_cs, sample_data, None)
                }
            } else if !is_image_mask && !has_explicit_cs {
                let pixels = width as usize * height as usize;
                if pixels > 0 {
                    let n_comps = sample_data.len() / pixels;
                    // For 4-component JPX images, check JP2 metadata to distinguish
                    // RGBA (sRGB + alpha) from CMYK. Without this, RGBA images get
                    // misidentified as CMYK, producing wrong colors (e.g., orange → blue).
                    if n_comps == 4 && self.is_jpx_rgba(obj) {
                        if smask_in_data >= 1 {
                            // SMaskInData: the JP2 alpha channel is the soft mask.
                            // Premultiply alpha (tiny-skia expects premultiplied RGBA).
                            let mut rgba = sample_data;
                            for chunk in rgba.chunks_exact_mut(4) {
                                let a = chunk[3] as u16;
                                if a == 0 {
                                    chunk[0] = 0;
                                    chunk[1] = 0;
                                    chunk[2] = 0;
                                } else if a < 255 {
                                    chunk[0] = ((chunk[0] as u16 * a + 127) / 255) as u8;
                                    chunk[1] = ((chunk[1] as u16 * a + 127) / 255) as u8;
                                    chunk[2] = ((chunk[2] as u16 * a + 127) / 255) as u8;
                                }
                            }
                            (None, rgba, None)
                        } else {
                            // No embedded mask — strip alpha from RGBA → RGB.
                            let mut rgb = Vec::with_capacity(pixels * 3);
                            for chunk in sample_data.chunks_exact(4) {
                                rgb.push(chunk[0]);
                                rgb.push(chunk[1]);
                                rgb.push(chunk[2]);
                            }
                            (Some(ResolvedColorSpace::DeviceRGB), rgb, None)
                        }
                    } else {
                        let cs = match n_comps {
                            1 => ResolvedColorSpace::DeviceGray,
                            4 => ResolvedColorSpace::DeviceCMYK,
                            _ => ResolvedColorSpace::DeviceRGB,
                        };
                        (Some(cs), sample_data, None)
                    }
                } else {
                    (resolved_cs, sample_data, None)
                }
            } else {
                (resolved_cs, sample_data, None)
            };

        // Image matrix: [width 0 0 -height 0 height] maps unit square to image
        let image_matrix =
            Matrix::new(width as f64, 0.0, 0.0, -(height as f64), 0.0, height as f64);

        // Imagemask with shading pattern fill: use SoftMasked to clip shading to mask shape
        if is_image_mask && self.gstate.fill_shading_pattern.is_some() {
            let shading_box = self.gstate.fill_shading_pattern.clone().unwrap();
            let row_bytes = width.div_ceil(8);
            let mut gray = vec![0u8; (width * height) as usize];
            for y in 0..height {
                for x in 0..width {
                    let byte_idx = (y * row_bytes + x / 8) as usize;
                    let bit_idx = 7 - (x % 8);
                    let bit = if byte_idx < sample_data.len() {
                        (sample_data[byte_idx] >> bit_idx) & 1
                    } else {
                        0
                    };
                    let painted = if polarity { bit == 1 } else { bit == 0 };
                    gray[(y * width + x) as usize] = if painted { 255 } else { 0 };
                }
            }

            let mut mask_dl = DisplayList::new();
            mask_dl.push(DisplayElement::Image {
                sample_data: Arc::new(gray),
                params: ImageParams {
                    width,
                    height,
                    color_space: ImageColorSpace::DeviceGray,
                    bits_per_component: 8,
                    ctm: self.gstate.ctm,
                    image_matrix,
                    interpolate: false,
                    mask_color: None,
                    alpha: 1.0,
                    blend_mode: 0,
                    overprint: false,
                    overprint_mode: 0,
                    opm_paired: false,
                    painted_channels: 0,
                    alpha_is_shape: false,
                    rendering_intent: 0,
                },
            });

            let mut content_dl = DisplayList::new();
            for elem in shading_box.0.elements() {
                content_dl.push(elem.clone());
            }

            let corners = [
                self.gstate.ctm.transform_point(0.0, 0.0),
                self.gstate.ctm.transform_point(width as f64, 0.0),
                self.gstate.ctm.transform_point(0.0, height as f64),
                self.gstate.ctm.transform_point(width as f64, height as f64),
            ];
            let x_min = corners.iter().map(|c| c.0).fold(f64::INFINITY, f64::min);
            let y_min = corners.iter().map(|c| c.1).fold(f64::INFINITY, f64::min);
            let x_max = corners
                .iter()
                .map(|c| c.0)
                .fold(f64::NEG_INFINITY, f64::max);
            let y_max = corners
                .iter()
                .map(|c| c.1)
                .fold(f64::NEG_INFINITY, f64::max);

            let parent_clip_bbox = self.current_clip_bbox();
            self.display_list.push(DisplayElement::SoftMasked {
                mask: mask_dl,
                content: content_dl,
                params: SoftMaskParams {
                    subtype: SoftMaskSubtype::Luminosity,
                    bbox: [x_min, y_min, x_max, y_max],
                    backdrop_color: None,
                    transfer_invert: false,
                    has_nested_mask_scope: false,
                    parent_clip_bbox,
                },
                mask_cache: Arc::new(Mutex::new(None)),
            });
            return Ok(());
        }

        // OPM 1 + overprint on + CMYK all-zero fill + no pattern: "no ink" means
        // don't paint.  Skip the ImageMask so underlying content shows through.
        // When a pattern IS active, the pattern provides the real color and
        // the ImageMask acts as a text stencil — it must still render.
        // NOTE: OPM only takes effect when overprint (OP/op) is enabled.
        if is_image_mask
            && self.gstate.overprint
            && self.gstate.overprint_mode == 1
            && self.gstate.fill_pattern.is_none()
            && self.gstate.fill_shading_pattern.is_none()
            && self.gstate.fill_color.native_cmyk == Some((0.0, 0.0, 0.0, 0.0))
        {
            return Ok(());
        }

        // Imagemask with tiling pattern fill: use SoftMasked to clip pattern to mask shape.
        // The ImageMask provides the text stencil and the pattern provides the color.
        // We emit tile images directly (composing their CTM with the pattern matrix)
        // rather than using PatternFill, because the pattern tile covers the full page
        // and each strip has unique image data — the tiling renderer can't handle this
        // efficiently.
        if is_image_mask && self.gstate.fill_pattern.is_some() {
            let pattern = self.gstate.fill_pattern.clone().unwrap();
            let row_bytes = width.div_ceil(8);
            let mut gray = vec![0u8; (width * height) as usize];
            for y in 0..height {
                for x in 0..width {
                    let byte_idx = (y * row_bytes + x / 8) as usize;
                    let bit_idx = 7 - (x % 8);
                    let bit = if byte_idx < sample_data.len() {
                        (sample_data[byte_idx] >> bit_idx) & 1
                    } else {
                        0
                    };
                    let painted = if polarity { bit == 1 } else { bit == 0 };
                    gray[(y * width + x) as usize] = if painted { 255 } else { 0 };
                }
            }

            let mut mask_dl = DisplayList::new();
            mask_dl.push(DisplayElement::Image {
                sample_data: Arc::new(gray),
                params: ImageParams {
                    width,
                    height,
                    color_space: ImageColorSpace::DeviceGray,
                    bits_per_component: 8,
                    ctm: self.gstate.ctm,
                    image_matrix,
                    interpolate: false,
                    mask_color: None,
                    alpha: 1.0,
                    blend_mode: 0,
                    overprint: false,
                    overprint_mode: 0,
                    opm_paired: false,
                    painted_channels: 0,
                    alpha_is_shape: false,
                    rendering_intent: 0,
                },
            });

            let corners = [
                self.gstate.ctm.transform_point(0.0, 0.0),
                self.gstate.ctm.transform_point(width as f64, 0.0),
                self.gstate.ctm.transform_point(0.0, height as f64),
                self.gstate.ctm.transform_point(width as f64, height as f64),
            ];
            let x_min = corners.iter().map(|c| c.0).fold(f64::INFINITY, f64::min);
            let y_min = corners.iter().map(|c| c.1).fold(f64::INFINITY, f64::min);
            let x_max = corners
                .iter()
                .map(|c| c.0)
                .fold(f64::NEG_INFINITY, f64::max);
            let y_max = corners
                .iter()
                .map(|c| c.1)
                .fold(f64::NEG_INFINITY, f64::max);

            // Emit tile images directly as content, composing their CTM with
            // the pattern matrix to place them in device space.
            let pm = &pattern.pattern_matrix;
            let mut content_dl = DisplayList::new();
            for elem in pattern.tile.elements() {
                if let DisplayElement::Image {
                    sample_data: sd,
                    params: ip,
                } = elem
                {
                    let dev_ctm = pm.multiply(&ip.ctm);
                    content_dl.push(DisplayElement::Image {
                        sample_data: sd.clone(),
                        params: ImageParams {
                            ctm: dev_ctm,
                            ..ip.clone()
                        },
                    });
                }
            }

            let parent_clip_bbox = self.current_clip_bbox();
            self.display_list.push(DisplayElement::SoftMasked {
                mask: mask_dl,
                content: content_dl,
                params: SoftMaskParams {
                    subtype: SoftMaskSubtype::Luminosity,
                    bbox: [x_min, y_min, x_max, y_max],
                    backdrop_color: None,
                    transfer_invert: false,
                    has_nested_mask_scope: false,
                    parent_clip_bbox,
                },
                mask_cache: Arc::new(Mutex::new(None)),
            });
            return Ok(());
        }

        // For multi-input DeviceN images, evaluate the tinting function directly
        // per pixel to avoid lossy N-D lookup table interpolation.  A pre-sampled
        // table with spd^N entries can never faithfully represent all 256^N possible
        // 8-bit input combinations for N≥2.  Direct evaluation is exact and fast
        // enough for typical image sizes.
        let (color_space, sample_data) = if !is_image_mask
            && let Some(ResolvedColorSpace::DeviceN {
                names,
                alt,
                tint_fn: Some(func),
            }) = resolved_cs.as_ref()
            && names.len() >= 2
            && matches!(
                alt.as_ref(),
                ResolvedColorSpace::DeviceGray | ResolvedColorSpace::DeviceRGB
            ) {
            let ni = names.len();
            let npixels = width as usize * height as usize;
            let mut rgba = vec![255u8; npixels * 4];
            let mut inputs = vec![0.0f64; ni];
            for i in 0..npixels {
                let si = i * ni;
                for (c, inp) in inputs.iter_mut().enumerate() {
                    *inp = sample_data.get(si + c).copied().unwrap_or(0) as f64 / 255.0;
                }
                let out = func.evaluate(&inputs);
                let (r, g, b) = color_space::alt_comps_to_rgb_f64(&out, alt);
                let pi = i * 4;
                rgba[pi] = r;
                rgba[pi + 1] = g;
                rgba[pi + 2] = b;
            }
            (ImageColorSpace::PreconvertedRGBA, rgba)
        } else if is_image_mask {
            (
                ImageColorSpace::Mask {
                    color: self.gstate.fill_color.clone(),
                    polarity,
                    spot_color: self.gstate.fill_spot_color.clone(),
                },
                sample_data,
            )
        } else if let Some(ref rcs) = resolved_cs {
            (to_image_color_space(rcs), sample_data)
        } else {
            // resolved_cs is None for JPX RGBA with SMaskInData — already RGBA
            (ImageColorSpace::PreconvertedRGBA, sample_data)
        };

        // JPXDecode with internal palette (pclr): hayro-jpeg2000 applies the JP2 palette
        // and returns expanded data (e.g. 3-component RGB for a 1-component codestream).
        // Per PDF spec 7.4.9, the JP2 palette is applied before the PDF color space.
        // When the PDF says Indexed but the JP2 already expanded the palette,
        // switch to the base color space since the data is already depalettized.
        let color_space = if !is_image_mask {
            if let ImageColorSpace::Indexed { base, .. } = &color_space {
                let expected_1comp = (width * height) as usize;
                let base_n = base.num_components() as usize;
                if sample_data.len() == expected_1comp * base_n && base_n > 1 {
                    *base.clone()
                } else {
                    color_space
                }
            } else {
                color_space
            }
        } else {
            color_space
        };

        let interpolate = dict
            .get(b"Interpolate")
            .and_then(|o| match o {
                PdfObj::Bool(b) => Some(*b),
                _ => None,
            })
            .unwrap_or(false);

        // Mask color (for color-key masking) or explicit stencil mask (stream ref)
        let (mask_color, explicit_mask_data) = match dict.get(b"Mask") {
            Some(PdfObj::Array(arr)) => {
                // Color-key mask: array of component ranges
                let mc: Vec<u8> = arr
                    .iter()
                    .filter_map(|o| o.as_int().map(|n| n as u8))
                    .collect();
                (Some(mc), None)
            }
            Some(_mask_obj) => {
                // Explicit stencil mask: indirect reference to 1-bit ImageMask stream
                let mask_alpha = self
                    .resolve_explicit_mask(dict, width, height)
                    .unwrap_or(None);
                (None, mask_alpha)
            }
            None => (None, None),
        };

        // Convert data if BPC != 8 (but NOT for image masks — keep raw 1-bit data).
        // JPXDecode (JPEG 2000) and DCTDecode (JPEG) always produce 8-bit output
        // regardless of the /BitsPerComponent value in the PDF dict.
        let is_jpx = filter_is_jpx;
        let is_dct = filter_is_dct;
        let is_indexed = matches!(&color_space, ImageColorSpace::Indexed { .. });
        // Expand sub-byte samples (1/2/4 BPC) to 8-bit since they're packed
        // with geometry-dependent alignment. Downsample 16-bit to 8-bit (take
        // high byte) — downstream ICC and color conversion assumes 8-bit data.
        let (sample_data, display_bpc) =
            if is_image_mask || bpc == 8 || bpc == 0 || is_jpx || is_dct {
                (sample_data, if is_dct || is_jpx { 8 } else { bpc })
            } else if bpc == 16 {
                // Take high byte of each 16-bit big-endian sample
                (sample_data.chunks(2).map(|c| c[0]).collect(), 8)
            } else if bpc > 8 {
                (sample_data, bpc)
            } else {
                (
                    expand_bits_to_bytes(
                        &sample_data,
                        bpc,
                        width,
                        height,
                        color_space.num_components(),
                        is_indexed,
                    ),
                    8,
                )
            };

        // Apply /Decode array if present (maps sample values to color component values).
        // Default for most color spaces is [0 1 0 1 ...] (identity).
        // For Indexed color spaces, default is [0 2^bpc-1] and values are indices.
        // CMYK images may use [1 0 1 0 1 0 1 0] to invert values.
        let sample_data = if !is_image_mask {
            if let Some(decode) = dict.get_array(b"Decode") {
                let n_comps = color_space.num_components() as usize;
                let decode_vals: Vec<f64> = decode.iter().filter_map(|o| o.as_f64()).collect();
                if decode_vals.len() >= n_comps * 2 {
                    let effective_bpc = if is_jpx || is_dct { 8 } else { bpc };
                    let max_sample = ((1u32 << effective_bpc) - 1) as f64;
                    // Check if it's the default Decode for this color space.
                    // Indexed: default is [0 max_sample]; others: [0 1 0 1 ...].
                    let is_default = if is_indexed {
                        decode_vals.len() == 2
                            && (decode_vals[0]).abs() < 1e-6
                            && (decode_vals[1] - max_sample).abs() < 1e-6
                    } else {
                        decode_vals.chunks(2).all(|pair| {
                            pair.len() == 2
                                && (pair[0] - 0.0).abs() < 1e-6
                                && (pair[1] - 1.0).abs() < 1e-6
                        })
                    };
                    if !is_default {
                        // After expand_bits_to_bytes: indexed data keeps raw values
                        // (0 to 2^bpc-1), non-indexed data is scaled to 0-255.
                        let max_val = if is_indexed {
                            ((1u32 << effective_bpc) - 1) as f64
                        } else {
                            255.0f64
                        };
                        let mut result = Vec::with_capacity(sample_data.len());
                        if is_indexed {
                            // Indexed: Decode maps sample values to index values (integer range)
                            let d_min = decode_vals[0];
                            let d_max = decode_vals[1];
                            for &sample in sample_data.iter() {
                                let val = d_min + (sample as f64 / max_val) * (d_max - d_min);
                                result.push(val.round().clamp(0.0, 255.0) as u8);
                            }
                        } else {
                            // Non-indexed: Decode maps to normalized [0,1] component values
                            for (i, &sample) in sample_data.iter().enumerate() {
                                let comp = i % n_comps;
                                let d_min = decode_vals[comp * 2];
                                let d_max = decode_vals[comp * 2 + 1];
                                let val = d_min + (sample as f64 / max_val) * (d_max - d_min);
                                result.push((val.clamp(0.0, 1.0) * 255.0 + 0.5) as u8);
                            }
                        }
                        result
                    } else {
                        sample_data
                    }
                } else {
                    sample_data
                }
            } else {
                sample_data
            }
        } else {
            sample_data
        };

        // In CMYK page groups, route DeviceGray-derived images (DeviceGray
        // itself, Separation with gray alt, DeviceN with gray alt) through
        // the K plate so they composite equivalently to DeviceCMYK 0/0/0/(1−g).
        // Required by GWG 17.3 (JBIG2 compression) and GWG 23.0's "4 different
        // Grays" test.
        let (sample_data, color_space, resolved_cs) = if !is_image_mask {
            let was_device_gray = matches!(color_space, ImageColorSpace::DeviceGray);
            let (new_cs, new_data) =
                self.cmyk_group_promote_image(color_space, sample_data, width, height);
            let new_resolved = if was_device_gray && matches!(new_cs, ImageColorSpace::DeviceCMYK) {
                Some(ResolvedColorSpace::DeviceCMYK)
            } else {
                resolved_cs
            };
            (new_data, new_cs, new_resolved)
        } else {
            (sample_data, color_space, resolved_cs)
        };

        // Register the ICC profile with the cache so the rasterizer can find
        // it by hash.  Conversion itself is deferred to samples_to_rgba() so
        // only pixels that actually land on screen pay the color-transform cost.
        if !is_image_mask {
            if let Some(ref rcs) = resolved_cs {
                register_icc_profile(rcs, &mut self.icc_cache);
            }
        }

        // Handle SMask (soft mask / alpha channel).
        // Emit the image and its SMask as a SoftMasked display element so the
        // renderer scales them independently, preserving visible edges at hard
        // alpha boundaries (e.g. text outlines on transparent backgrounds).
        // When the mask is larger than the image (e.g., 1-bit text mask on a 2×2
        // color image), upscale the image to the mask dimensions to preserve detail.
        let smask_result = if !is_image_mask {
            let dict_smask = self.resolve_smask(dict, width, height)?;
            // Use SMaskInData alpha when no explicit /SMask entry exists
            if dict_smask.is_none() {
                if let Some(alpha) = smask_in_data_alpha {
                    Some((alpha, width, height, None))
                } else {
                    None
                }
            } else {
                dict_smask
            }
        } else {
            None
        };

        // Handle explicit stencil mask (/Mask pointing to 1-bit ImageMask stream).
        // When the mask is larger than the image (MRC scanned PDFs), upscale the
        // image to the mask dimensions so the high-res edge detail is preserved.
        let (sample_data, color_space, width, height) =
            if let Some((mask_alpha, mw, mh)) = explicit_mask_data {
                // Expand Indexed data to the base color space before upscaling,
                // so bilinear interpolation blends actual colors, not indices.
                let (up_data, up_cs) = if let ImageColorSpace::Indexed {
                    base,
                    hival,
                    lookup,
                } = &color_space
                {
                    let n_base = base.num_components() as usize;
                    let n_pixels = (width * height) as usize;
                    let mut expanded = vec![0u8; n_pixels * n_base];
                    for i in 0..n_pixels {
                        let idx = sample_data.get(i).copied().unwrap_or(0) as usize;
                        let idx = idx.min(*hival as usize);
                        let offset = idx * n_base;
                        for c in 0..n_base {
                            expanded[i * n_base + c] = lookup.get(offset + c).copied().unwrap_or(0);
                        }
                    }
                    (expanded, *base.clone())
                } else {
                    (sample_data, color_space)
                };
                let (img_data, img_w, img_h) = if mw > width || mh > height {
                    // Upscale image to mask dimensions using bilinear interpolation
                    let upscaled = bilinear_upsample_image(&up_data, width, height, mw, mh, &up_cs);
                    (upscaled, mw, mh)
                } else {
                    (up_data, width, height)
                };
                let rgba = merge_rgb_with_smask(
                    &img_data,
                    &mask_alpha,
                    &up_cs,
                    img_w,
                    img_h,
                    Some(&self.icc_cache),
                );
                (rgba, ImageColorSpace::PreconvertedRGBA, img_w, img_h)
            } else {
                (sample_data, color_space, width, height)
            };

        // Apply transfer functions to image pixel data (colorizes grayscale charts etc.)
        let sample_data = if !is_image_mask && self.gstate.transfer.has_functions() {
            let n_comps = color_space.num_components() as usize;
            if n_comps >= 3 {
                let mut data = sample_data;
                apply_transfer_to_image(&mut data, &self.gstate.transfer, n_comps);
                data
            } else {
                sample_data
            }
        } else {
            sample_data
        };

        // Recompute image_matrix if dimensions changed (e.g. upscaled to match mask)
        let image_matrix =
            Matrix::new(width as f64, 0.0, 0.0, -(height as f64), 0.0, height as f64);

        // For K-only Indexed/DeviceCMYK palettes (grayscale images encoded as
        // CMYK), narrow painted_channels to CMYK_K so the overprint renderer
        // only paints the K channel.  This preserves spot-color contributions
        // on C/M/Y underneath — required by GWG 3.1 (Gray Image Overprint).
        // Non-K palettes keep CMYK_ALL so all channels are painted, matching
        // the PDF spec rule that OPM 1 per-channel zeroing does not apply to
        // Indexed color spaces (required by GWG 1.0 h/i).
        let painted_channels_override = if let ImageColorSpace::Indexed {
            base,
            hival,
            lookup,
        } = &color_space
        {
            if matches!(
                base.as_ref(),
                ImageColorSpace::DeviceCMYK | ImageColorSpace::ICCBased { n: 4, .. }
            ) {
                let n_entries = (*hival as usize + 1).min(lookup.len() / 4);
                let is_k_only = n_entries > 0
                    && (0..n_entries).all(|i| {
                        let off = i * 4;
                        lookup.get(off).copied().unwrap_or(0) == 0
                            && lookup.get(off + 1).copied().unwrap_or(0) == 0
                            && lookup.get(off + 2).copied().unwrap_or(0) == 0
                    });
                if is_k_only {
                    stet_graphics::device::CMYK_K
                } else {
                    stet_graphics::device::CMYK_ALL
                }
            } else {
                resolved_cs
                    .as_ref()
                    .map(painted_channels_for_cs)
                    .unwrap_or(self.gstate.fill_painted_channels)
            }
        } else {
            resolved_cs
                .as_ref()
                .map(painted_channels_for_cs)
                .unwrap_or(self.gstate.fill_painted_channels)
        };

        let image_params = ImageParams {
            width,
            height,
            color_space,
            bits_per_component: display_bpc as u8,
            ctm: self.gstate.ctm,
            image_matrix,
            interpolate,
            mask_color,
            alpha: self.gstate.fill_alpha,
            blend_mode: self.gstate.blend_mode,
            overprint: self.gstate.overprint,
            overprint_mode: self.gstate.overprint_mode,
            opm_paired: self.gstate.opm_paired,
            painted_channels: painted_channels_override,
            alpha_is_shape: self.gstate.alpha_is_shape,
            rendering_intent: image_intent,
        };

        // When an SMask is present, emit as SoftMasked so the renderer scales
        // image and mask independently, preserving edge detail at hard alpha
        // boundaries that premultiplied-alpha averaging would make invisible.
        if let Some((smask_data, mw, mh, matte)) = smask_result {
            // Upscale image to mask dimensions if the mask is larger — this
            // preserves sharp mask edges (e.g. MRC text masks on low-res images).
            // Cap the target pixel count to avoid allocating enormous buffers
            // when the mask is vastly larger than the image (e.g. 34862×4332
            // mask on a 2×2 image in issue16263.pdf). The limit is generous
            // enough for high-DPI and zoomed rendering but prevents pathological
            // cases from consuming gigabytes of memory.
            const MAX_PIXELS: u64 = 16_000_000; // ~4096×4096
            let mut target_w = mw.max(width);
            let mut target_h = mh.max(height);
            if (target_w as u64) * (target_h as u64) > MAX_PIXELS {
                let scale = (MAX_PIXELS as f64 / (target_w as f64 * target_h as f64)).sqrt();
                target_w = (target_w as f64 * scale).ceil() as u32;
                target_h = (target_h as f64 * scale).ceil() as u32;
            }
            let (sample_data, width, height) = if target_w > width || target_h > height {
                let upscaled = bilinear_upsample_image(
                    &sample_data,
                    width,
                    height,
                    target_w,
                    target_h,
                    &image_params.color_space,
                );
                (upscaled, target_w, target_h)
            } else {
                (sample_data, width, height)
            };

            // Resample SMask to image dimensions if they differ
            let smask_data = if mw != width || mh != height {
                let mut resampled = vec![0u8; (width * height) as usize];
                for y in 0..height {
                    let sy = (y as u64 * mh as u64 / height as u64) as u32;
                    for x in 0..width {
                        let sx = (x as u64 * mw as u64 / width as u64) as u32;
                        resampled[(y * width + x) as usize] = smask_data
                            .get((sy * mw + sx) as usize)
                            .copied()
                            .unwrap_or(0);
                    }
                }
                resampled
            } else {
                smask_data
            };

            // Un-premultiply image colors when Matte is specified (PDF spec 11.6.5.3).
            // The image data was pre-composited against the Matte color; reverse this
            // to recover the original colors before alpha compositing.
            let sample_data = if let Some(ref mc) = matte {
                let n_comps = image_params.color_space.num_components() as usize;
                if mc.len() >= n_comps && n_comps >= 3 {
                    let mut out = sample_data;
                    let pixels = (width * height) as usize;
                    for i in 0..pixels {
                        let a = smask_data[i] as f64 / 255.0;
                        if a > 0.0 && a < 1.0 {
                            for c in 0..n_comps.min(3) {
                                let m = (mc[c] * 255.0).clamp(0.0, 255.0);
                                let premul = out[i * n_comps + c] as f64;
                                let orig = m + (premul - m) / a;
                                out[i * n_comps + c] = orig.round().clamp(0.0, 255.0) as u8;
                            }
                        }
                    }
                    out
                } else {
                    sample_data
                }
            } else {
                sample_data
            };

            // Cache the fully-processed image data for reuse (Arc for cheap cloning).
            let sample_arc = Arc::new(sample_data);
            let smask_arc = Arc::new(smask_data);
            if let PdfObj::Ref(obj_num, _) = obj {
                self.image_cache.insert(
                    *obj_num,
                    CachedImage {
                        sample_data: Arc::clone(&sample_arc),
                        width,
                        height,
                        color_space: image_params.color_space.clone(),
                        bits_per_component: image_params.bits_per_component,
                        interpolate,
                        mask_color: image_params.mask_color.clone(),
                        painted_channels: image_params.painted_channels,
                        smask: Some((Arc::clone(&smask_arc), width, height, matte.clone())),
                        rendering_intent: image_params.rendering_intent,
                    },
                );
            }

            let image_matrix =
                Matrix::new(width as f64, 0.0, 0.0, -(height as f64), 0.0, height as f64);

            let mut mask_dl = DisplayList::new();
            mask_dl.push(DisplayElement::Image {
                sample_data: smask_arc,
                params: ImageParams {
                    width,
                    height,
                    color_space: ImageColorSpace::DeviceGray,
                    bits_per_component: 8,
                    ctm: self.gstate.ctm,
                    image_matrix,
                    interpolate,
                    mask_color: None,
                    alpha: 1.0,
                    blend_mode: 0,
                    overprint: false,
                    overprint_mode: 0,
                    opm_paired: false,
                    painted_channels: 0,
                    alpha_is_shape: false,
                    rendering_intent: 0,
                },
            });

            let mut content_dl = DisplayList::new();
            content_dl.push(DisplayElement::Image {
                sample_data: sample_arc,
                params: ImageParams {
                    width,
                    height,
                    image_matrix,
                    ..image_params
                },
            });

            let corners = [
                self.gstate.ctm.transform_point(0.0, 0.0),
                self.gstate.ctm.transform_point(1.0, 0.0),
                self.gstate.ctm.transform_point(0.0, 1.0),
                self.gstate.ctm.transform_point(1.0, 1.0),
            ];
            let x_min = corners.iter().map(|c| c.0).fold(f64::INFINITY, f64::min);
            let y_min = corners.iter().map(|c| c.1).fold(f64::INFINITY, f64::min);
            let x_max = corners
                .iter()
                .map(|c| c.0)
                .fold(f64::NEG_INFINITY, f64::max);
            let y_max = corners
                .iter()
                .map(|c| c.1)
                .fold(f64::NEG_INFINITY, f64::max);

            let parent_clip_bbox = self.current_clip_bbox();
            self.display_list.push(DisplayElement::SoftMasked {
                mask: mask_dl,
                content: content_dl,
                params: SoftMaskParams {
                    subtype: SoftMaskSubtype::Luminosity,
                    bbox: [x_min, y_min, x_max, y_max],
                    backdrop_color: None,
                    transfer_invert: false,
                    has_nested_mask_scope: false,
                    parent_clip_bbox,
                },
                mask_cache: Arc::new(Mutex::new(None)),
            });
        } else {
            // Cache plain image for reuse (Arc for cheap cloning).
            let sample_arc = Arc::new(sample_data);
            if let PdfObj::Ref(obj_num, _) = obj {
                self.image_cache.insert(
                    *obj_num,
                    CachedImage {
                        sample_data: Arc::clone(&sample_arc),
                        width,
                        height,
                        color_space: image_params.color_space.clone(),
                        bits_per_component: image_params.bits_per_component,
                        interpolate,
                        mask_color: image_params.mask_color.clone(),
                        painted_channels: image_params.painted_channels,
                        smask: None,
                        rendering_intent: image_params.rendering_intent,
                    },
                );
            }

            self.display_list.push(DisplayElement::Image {
                sample_data: sample_arc,
                params: image_params,
            });
        }
        Ok(())
    }

    /// Build a CachedImage, pre-downscaling if the image is much larger than
    /// its device-pixel target size (detected from the current CTM).
    #[allow(clippy::too_many_arguments)]
    /// Emit a display element from a cached image, applying current graphics state.
    /// The cache already contains pre-downscaled data when applicable.
    fn emit_cached_image(&mut self, cached: CachedImage) -> Result<(), PdfError> {
        let (sample_data, smask, width, height) = (
            cached.sample_data,
            cached.smask,
            cached.width,
            cached.height,
        );

        let image_matrix =
            Matrix::new(width as f64, 0.0, 0.0, -(height as f64), 0.0, height as f64);
        let image_params = ImageParams {
            width,
            height,
            color_space: cached.color_space,
            bits_per_component: cached.bits_per_component,
            ctm: self.gstate.ctm,
            image_matrix,
            interpolate: cached.interpolate,
            mask_color: cached.mask_color,
            alpha: self.gstate.fill_alpha,
            blend_mode: self.gstate.blend_mode,
            overprint: self.gstate.overprint,
            overprint_mode: self.gstate.overprint_mode,
            opm_paired: self.gstate.opm_paired,
            painted_channels: cached.painted_channels,
            alpha_is_shape: self.gstate.alpha_is_shape,
            rendering_intent: cached.rendering_intent,
        };

        if let Some((smask_data, sw, sh, _matte)) = smask {
            let mut mask_dl = DisplayList::new();
            mask_dl.push(DisplayElement::Image {
                sample_data: smask_data,
                params: ImageParams {
                    width: sw,
                    height: sh,
                    color_space: ImageColorSpace::DeviceGray,
                    bits_per_component: 8,
                    ctm: self.gstate.ctm,
                    image_matrix,
                    interpolate: cached.interpolate,
                    mask_color: None,
                    alpha: 1.0,
                    blend_mode: 0,
                    overprint: false,
                    overprint_mode: 0,
                    opm_paired: false,
                    painted_channels: 0,
                    alpha_is_shape: false,
                    rendering_intent: 0,
                },
            });

            let mut content_dl = DisplayList::new();
            content_dl.push(DisplayElement::Image {
                sample_data,
                params: ImageParams {
                    width,
                    height,
                    image_matrix,
                    ..image_params
                },
            });

            let corners = [
                self.gstate.ctm.transform_point(0.0, 0.0),
                self.gstate.ctm.transform_point(1.0, 0.0),
                self.gstate.ctm.transform_point(0.0, 1.0),
                self.gstate.ctm.transform_point(1.0, 1.0),
            ];
            let x_min = corners.iter().map(|c| c.0).fold(f64::INFINITY, f64::min);
            let y_min = corners.iter().map(|c| c.1).fold(f64::INFINITY, f64::min);
            let x_max = corners
                .iter()
                .map(|c| c.0)
                .fold(f64::NEG_INFINITY, f64::max);
            let y_max = corners
                .iter()
                .map(|c| c.1)
                .fold(f64::NEG_INFINITY, f64::max);

            let parent_clip_bbox = self.current_clip_bbox();
            self.display_list.push(DisplayElement::SoftMasked {
                mask: mask_dl,
                content: content_dl,
                params: SoftMaskParams {
                    subtype: SoftMaskSubtype::Luminosity,
                    bbox: [x_min, y_min, x_max, y_max],
                    backdrop_color: None,
                    transfer_invert: false,
                    has_nested_mask_scope: false,
                    parent_clip_bbox,
                },
                mask_cache: Arc::new(Mutex::new(None)),
            });
        } else {
            self.display_list.push(DisplayElement::Image {
                sample_data,
                params: image_params,
            });
        }
        Ok(())
    }

    /// Resolve an SMask (soft mask) from an image dict.
    /// Returns `(alpha_data, mask_width, mask_height, matte)` at the mask's native
    /// resolution so the caller can upscale the image if the mask is larger.
    /// The optional Matte array contains the pre-multiplication color (PDF spec 11.6.5.3).
    fn resolve_smask(
        &self,
        dict: &PdfDict,
        image_w: u32,
        image_h: u32,
    ) -> Result<Option<(Vec<u8>, u32, u32, Option<Vec<f64>>)>, PdfError> {
        let smask_ref = match dict.get(b"SMask") {
            Some(obj) => obj.clone(),
            None => return Ok(None),
        };
        let smask_obj = self.resolver.deref(&smask_ref)?;
        let smask_dict = match smask_obj.as_dict() {
            Some(d) => d,
            None => return Ok(None),
        };
        // Fall back to parent image dimensions when the SMask dict is
        // malformed (e.g. /Height missing — issue19611.pdf).
        let sw = smask_dict.get_int(b"Width").unwrap_or(image_w as i64) as u32;
        let sh = smask_dict.get_int(b"Height").unwrap_or(image_h as i64) as u32;
        if sw == 0 || sh == 0 {
            return Ok(None);
        }
        let bpc = smask_dict.get_int(b"BitsPerComponent").unwrap_or(8) as u32;
        let data = self.resolver.stream_data_from_obj(&smask_ref)?;

        // Expand non-8-bit BPC: sub-byte (1/2/4) are packed bits;
        // 16-bit needs downsampling to 8-bit for alpha channel use.
        let mut data = if bpc == 8 {
            data
        } else if bpc == 16 {
            // Take high byte of each 16-bit sample
            data.chunks(2).map(|c| c[0]).collect()
        } else if bpc < 8 {
            expand_bits_to_bytes(&data, bpc, sw, sh, 1, false)
        } else {
            data
        };

        // Apply /Decode array if present (e.g. [1 0] inverts the mask)
        if let Some(decode) = smask_dict.get_array(b"Decode")
            && decode.len() >= 2
        {
            let d0 = decode[0].as_f64().unwrap_or(0.0);
            let d1 = decode[1].as_f64().unwrap_or(1.0);
            if (d0 - 1.0).abs() < 1e-6 && d1.abs() < 1e-6 {
                // /Decode [1 0] — invert all bytes
                for b in data.iter_mut() {
                    *b = 255 - *b;
                }
            } else if (d0).abs() > 1e-6 || (d1 - 1.0).abs() > 1e-6 {
                // General linear mapping: output = d0 + (d1-d0) * input/255
                for b in data.iter_mut() {
                    let v = d0 + (d1 - d0) * (*b as f64 / 255.0);
                    *b = (v * 255.0).round().clamp(0.0, 255.0) as u8;
                }
            }
        }

        // Parse /Matte array (pre-multiplication color, PDF spec 11.6.5.3)
        let matte = smask_dict
            .get_array(b"Matte")
            .map(|arr| arr.iter().filter_map(|o| o.as_f64()).collect::<Vec<_>>());

        Ok(Some((data, sw, sh, matte)))
    }

    /// Resolve an explicit stencil mask (/Mask stream ref) from an image dict.
    /// Returns (alpha_data, mask_width, mask_height).
    /// When the mask is larger than the image, returns the mask at its native
    /// resolution so the caller can upscale the image to match (preserving the
    /// high-resolution edge detail from MRC scanned PDFs).
    fn resolve_explicit_mask(
        &self,
        dict: &PdfDict,
        image_w: u32,
        image_h: u32,
    ) -> Result<Option<(Vec<u8>, u32, u32)>, PdfError> {
        let mask_ref = match dict.get(b"Mask") {
            Some(obj) => obj.clone(),
            None => return Ok(None),
        };
        let mask_obj = self.resolver.deref(&mask_ref)?;
        let mask_dict = match mask_obj.as_dict() {
            Some(d) => d,
            None => return Ok(None),
        };
        let mw = mask_dict.get_int(b"Width").unwrap_or(0) as u32;
        let mh = mask_dict.get_int(b"Height").unwrap_or(0) as u32;
        if mw == 0 || mh == 0 {
            return Ok(None);
        }
        let mask_data = self.resolver.stream_data_from_obj(&mask_ref)?;

        // Determine mask polarity from /Decode (default [0 1]: 0=painted=opaque)
        let invert = if let Some(decode) = mask_dict.get_array(b"Decode") {
            if decode.len() >= 2 {
                let d0 = decode[0].as_f64().unwrap_or(0.0);
                // [1 0] means 1=painted (invert normal polarity)
                d0 > 0.5
            } else {
                false
            }
        } else {
            false
        };

        // Expand 1-bit mask data to 8-bit alpha
        let row_bytes = mw.div_ceil(8);
        let mut alpha = vec![0u8; (mw * mh) as usize];
        for y in 0..mh {
            for x in 0..mw {
                let byte_idx = (y * row_bytes + x / 8) as usize;
                let bit_idx = 7 - (x % 8);
                let bit = if byte_idx < mask_data.len() {
                    (mask_data[byte_idx] >> bit_idx) & 1
                } else {
                    0
                };
                // In PDF, /ImageMask true with default Decode [0 1]:
                // bit=0 → painted (opaque), bit=1 → not painted (transparent)
                let opaque = if invert { bit == 1 } else { bit == 0 };
                alpha[(y * mw + x) as usize] = if opaque { 255 } else { 0 };
            }
        }

        // When mask is larger than the image, return it at native resolution.
        // The caller will upscale the image to match, preserving the mask's
        // high-resolution edge detail (critical for MRC scanned PDFs).
        // When mask is smaller, area-average downsample to image dimensions.
        if mw == image_w && mh == image_h {
            Ok(Some((alpha, mw, mh)))
        } else if mw >= image_w && mh >= image_h {
            // Mask is larger — return at native resolution
            Ok(Some((alpha, mw, mh)))
        } else {
            // Mask is smaller — area-average resample to image dimensions
            let mut resampled = vec![0u8; (image_w * image_h) as usize];
            let ratio_x = mw as f32 / image_w as f32;
            let ratio_y = mh as f32 / image_h as f32;
            for y in 0..image_h {
                let top_f = y as f32 * ratio_y;
                let bottom_f = (y + 1) as f32 * ratio_y;
                let top = (top_f as u32).min(mh - 1);
                let bottom = (bottom_f.ceil() as u32).min(mh);
                for x in 0..image_w {
                    let left_f = x as f32 * ratio_x;
                    let right_f = (x + 1) as f32 * ratio_x;
                    let left = (left_f as u32).min(mw - 1);
                    let right = (right_f.ceil() as u32).min(mw);
                    let mut sum = 0.0f32;
                    let mut weight = 0.0f32;
                    for sy in top..bottom {
                        let py_top = sy as f32;
                        let py_bot = (sy + 1) as f32;
                        let wy = py_bot.min(bottom_f) - py_top.max(top_f);
                        for sx in left..right {
                            let px_left = sx as f32;
                            let px_right = (sx + 1) as f32;
                            let wx = px_right.min(right_f) - px_left.max(left_f);
                            let w = wx * wy;
                            sum += alpha[(sy * mw + sx) as usize] as f32 * w;
                            weight += w;
                        }
                    }
                    resampled[(y * image_w + x) as usize] = if weight > 0.0 {
                        (sum / weight + 0.5).min(255.0) as u8
                    } else {
                        0
                    };
                }
            }
            Ok(Some((resampled, image_w, image_h)))
        }
    }

    /// Check if a JPXDecode image stream contains RGB+alpha (not CMYK).
    /// Peeks at the JP2 header metadata without re-decoding.
    fn is_jpx_rgba(&self, obj: &PdfObj) -> bool {
        #[cfg(feature = "jpx")]
        {
            if let Ok((raw, filters)) = self.resolver.raw_stream_and_filters(obj) {
                if filters
                    .iter()
                    .any(|f| matches!(f, crate::filters::Filter::JPXDecode))
                {
                    if let Some((color_channels, has_alpha)) = crate::filters::jpx_color_info(&raw)
                    {
                        return color_channels == 3 && has_alpha;
                    }
                }
            }
        }
        false
    }

    /// Handle a Form XObject (recursive content stream).
    fn handle_form_xobject(&mut self, obj: &PdfObj, dict: &PdfDict) -> Result<(), PdfError> {
        if self.depth >= 20 {
            return Err(PdfError::Other("Form XObject nesting too deep".into()));
        }

        // Get form's own resources (or inherit from page)
        let form_resources = if let Some(res_obj) = dict.get(b"Resources") {
            match self.resolver.deref(res_obj)? {
                PdfObj::Dict(d) => d,
                _ => self.resources.clone(),
            }
        } else {
            self.resources.clone()
        };

        // Form matrix
        let form_matrix = if let Some(vals) = deref_num_array(self.resolver, dict, b"Matrix") {
            if vals.len() == 6 {
                Matrix::new(vals[0], vals[1], vals[2], vals[3], vals[4], vals[5])
            } else {
                Matrix::identity()
            }
        } else {
            Matrix::identity()
        };

        // BBox clipping
        let bbox = if let Some(vals) = deref_num_array(self.resolver, dict, b"BBox") {
            if vals.len() == 4 {
                Some((vals[0], vals[1], vals[2], vals[3]))
            } else {
                None
            }
        } else {
            None
        };

        // Check for transparency group
        let is_transparency_group = self.is_transparency_group(dict);

        // Decompress form content stream
        let form_data = self.resolver.stream_data_from_obj(obj)?;

        // Save state (including font cache — form XObjects may have different
        // font resources with different encodings for the same resource name)
        self.gstate_stack.push(self.gstate.clone());
        let saved_stack_depth = self.gstate_stack.len();
        let saved_resources = std::mem::replace(&mut self.resources, form_resources);
        let saved_font_cache = std::mem::take(&mut self.font_cache);
        let saved_current_font = self.current_font.take();
        let saved_cs_index = self.cs_index.take(); // invalidate — form has its own resources
        let saved_content_stream_ctm = self.content_stream_ctm;
        let saved_mc_stack = std::mem::take(&mut self.mc_stack);
        // Save and clear current path — forms start with an empty path per PDF spec.
        // Without this, an unconsumed path from the parent content stream leaks into
        // the form and gets painted by the first paint operator inside the form.
        let saved_path = std::mem::take(&mut self.current_path);
        let saved_point = self.current_point.take();
        let saved_subpath = self.subpath_start.take();

        // Apply form matrix
        self.gstate.ctm = self.gstate.ctm.concat(&form_matrix);

        // Update content stream CTM — patterns inside this form map to
        // the form's initial coordinate system (CTM after form matrix).
        self.content_stream_ctm = self.gstate.ctm;

        if is_transparency_group {
            // Capture compositing parameters from the current state BEFORE
            // resetting alpha for the group's internal rendering.
            let group_blend_mode = self.gstate.blend_mode;
            let group_alpha = self.gstate.fill_alpha;

            // Reset alpha and soft mask inside the group: elements render at
            // full opacity. The inherited alpha is applied when compositing
            // the group as a whole, avoiding double-application of alpha.
            // Clearing soft_mask prevents the parent's SMask from leaking
            // into q/Q flush detection inside the group — without this,
            // inner Q restores see the parent SMask in the saved state and
            // skip flushing inner SMask scopes.
            self.gstate.fill_alpha = 1.0;
            self.gstate.stroke_alpha = 1.0;
            self.gstate.soft_mask = None;

            // Render group contents into a separate sub-DisplayList
            let mut group_list = DisplayList::new();
            std::mem::swap(&mut self.display_list, &mut group_list);

            // Save and clear soft mask scope — it belongs to the parent display list
            let saved_scope = self.soft_mask_scope.take();

            // Compute device-space bbox now, before interpret_stream modifies
            // the CTM via `cm` operators inside the form content.
            let device_bbox = self.compute_device_bbox(bbox);

            // Clip to BBox inside the group's display list
            if let Some((x0, y0, x1, y1)) = bbox {
                self.push_bbox_clip(x0, y0, x1, y1);
            }

            // Interpret form content into group_list (now in self.display_list)
            self.depth += 1;
            self.interpret_stream(&form_data)?;
            self.depth -= 1;

            // Flush any soft mask scope opened inside the group
            self.flush_soft_mask();

            // Swap back — group_list now contains the group's elements
            std::mem::swap(&mut self.display_list, &mut group_list);

            // Restore parent's soft mask scope
            self.soft_mask_scope = saved_scope;

            // Extract isolated and knockout flags from Group dict
            let isolated = self.get_group_isolated(dict);
            let knockout = self.get_group_knockout(dict);
            let color_space = self.get_group_color_space(dict);

            // Push Group element to parent display list
            self.display_list.push(DisplayElement::Group {
                elements: group_list,
                params: GroupParams {
                    bbox: device_bbox,
                    isolated,
                    knockout,
                    blend_mode: group_blend_mode,
                    alpha: group_alpha,
                    color_space,
                },
            });
        } else {
            // Non-transparency-group Form XObject: render inline (existing behavior)
            if let Some((x0, y0, x1, y1)) = bbox {
                self.push_bbox_clip(x0, y0, x1, y1);
            }

            // Compute visible Y range in form coordinates for early culling.
            // If the form is much taller than the visible area, skip offscreen
            // BT/ET blocks during interpretation (avoids font resolution and
            // glyph measurement for content that will never be rendered).
            let saved_cull = self.form_cull_y.take();
            if let Some((_x0, y0, _x1, y1)) = bbox {
                let form_height = (y1 - y0).abs();
                // Only cull if form is significantly larger than the page
                if form_height > 5000.0 {
                    // Compute visible Y range by inverse-transforming the page
                    // clip through the CTM. CTM maps form coords to device space.
                    let ctm = &self.gstate.ctm;
                    // For a simple scale+translate CTM (common case), inverse Y is:
                    // form_y = (device_y - ty) / d
                    if ctm.b.abs() < 1e-6 && ctm.c.abs() < 1e-6 && ctm.d.abs() > 1e-6 {
                        // device Y range is [0, page_height_px]
                        let page_h = self.initial_ctm.ty.abs();
                        let fy0 = (0.0 - ctm.ty) / ctm.d;
                        let fy1 = (page_h - ctm.ty) / ctm.d;
                        let (lo, hi) = if fy0 < fy1 { (fy0, fy1) } else { (fy1, fy0) };
                        // Add margin for text that extends above/below baseline
                        self.form_cull_y = Some((lo - 100.0, hi + 100.0));
                    }
                }
            }

            self.depth += 1;
            self.interpret_stream(&form_data)?;
            self.depth -= 1;

            self.form_cull_y = saved_cull;
        }

        // Unwind any unbalanced q's the form content left on the stack.
        // Form content streams often have q without matching Q (the end of
        // the stream implicitly unwinds).  Without this, the extra stack
        // entries cause our own pop below to restore the wrong gstate,
        // leaking state (e.g. alpha from ExtGState) into the parent scope.
        while self.gstate_stack.len() > saved_stack_depth {
            self.gstate_stack.pop();
        }

        // Restore state — check if clip needs resetting
        self.resources = saved_resources;
        self.font_cache = saved_font_cache;
        self.current_font = saved_current_font;
        self.cs_index = saved_cs_index;
        self.content_stream_ctm = saved_content_stream_ctm;
        self.current_path = saved_path;
        self.current_point = saved_point;
        self.subpath_start = saved_subpath;
        self.mc_stack = saved_mc_stack;
        if let Some(saved) = self.gstate_stack.pop() {
            let old_clip_version = self.gstate.clip_path_version;
            self.gstate = saved;
            // For non-group forms, restore clip if it changed
            if !is_transparency_group && self.gstate.clip_path_version != old_clip_version {
                self.restore_clip_from_stack();
            }
        }

        Ok(())
    }

    /// Check if a Form XObject dict has a /Group dict with /S /Transparency.
    fn is_transparency_group(&self, dict: &PdfDict) -> bool {
        let Some(group_obj) = dict.get(b"Group") else {
            return false;
        };
        let group_dict = match self.resolver.deref(group_obj) {
            Ok(PdfObj::Dict(d)) => d,
            _ => return false,
        };
        group_dict.get_name(b"S") == Some(b"Transparency")
    }

    /// Extract the /I (isolated) flag from a Form XObject's /Group dict.
    fn get_group_isolated(&self, dict: &PdfDict) -> bool {
        let Some(group_obj) = dict.get(b"Group") else {
            return false;
        };
        let group_dict = match self.resolver.deref(group_obj) {
            Ok(PdfObj::Dict(d)) => d,
            _ => return false,
        };
        match group_dict.get(b"I") {
            Some(PdfObj::Bool(b)) => *b,
            _ => false,
        }
    }

    /// Extract the /K (knockout) flag from a Form XObject's /Group dict.
    fn get_group_knockout(&self, dict: &PdfDict) -> bool {
        let Some(group_obj) = dict.get(b"Group") else {
            return false;
        };
        let group_dict = match self.resolver.deref(group_obj) {
            Ok(PdfObj::Dict(d)) => d,
            _ => return false,
        };
        match group_dict.get(b"K") {
            Some(PdfObj::Bool(b)) => *b,
            _ => false,
        }
    }

    /// Extract the `/CS` color space from a Form XObject's `/Group` dict and
    /// classify it for rendering purposes. Returns `Inherited` when the entry
    /// is missing or refers to a color space we don't categorise here.
    fn get_group_color_space(
        &self,
        dict: &PdfDict,
    ) -> stet_graphics::display_list::GroupColorSpace {
        use stet_graphics::display_list::GroupColorSpace;
        let Some(group_obj) = dict.get(b"Group") else {
            return GroupColorSpace::Inherited;
        };
        let group_dict = match self.resolver.deref(group_obj) {
            Ok(PdfObj::Dict(d)) => d,
            _ => return GroupColorSpace::Inherited,
        };
        let Some(cs_obj) = group_dict.get(b"CS") else {
            return GroupColorSpace::Inherited;
        };
        let cs_obj = match self.resolver.deref(cs_obj) {
            Ok(o) => o,
            Err(_) => return GroupColorSpace::Inherited,
        };
        match cs_obj {
            PdfObj::Name(n) => match n.as_slice() {
                b"DeviceGray" | b"CalGray" | b"G" => GroupColorSpace::DeviceGray,
                b"DeviceRGB" | b"CalRGB" | b"RGB" => GroupColorSpace::DeviceRGB,
                b"DeviceCMYK" | b"CMYK" => GroupColorSpace::DeviceCMYK,
                _ => GroupColorSpace::Inherited,
            },
            PdfObj::Array(arr) => {
                // [/ICCBased <<stream>>] — classify by N component count.
                if let Some(PdfObj::Name(name)) = arr.first()
                    && name.as_slice() == b"ICCBased"
                    && let Some(stream_obj) = arr.get(1)
                {
                    let stream_obj = match self.resolver.deref(stream_obj) {
                        Ok(o) => o,
                        Err(_) => return GroupColorSpace::Inherited,
                    };
                    if let PdfObj::Stream {
                        dict: stream_dict, ..
                    } = stream_obj
                        && let Some(n_obj) = stream_dict.get(b"N")
                        && let Some(n_val) = n_obj.as_int()
                    {
                        return match n_val {
                            1 => GroupColorSpace::DeviceGray,
                            3 => GroupColorSpace::DeviceRGB,
                            4 => GroupColorSpace::DeviceCMYK,
                            _ => GroupColorSpace::Inherited,
                        };
                    }
                }
                GroupColorSpace::Inherited
            }
            _ => GroupColorSpace::Inherited,
        }
    }

    /// Push a BBox clip path to the current display list.
    fn push_bbox_clip(&mut self, x0: f64, y0: f64, x1: f64, y1: f64) {
        let p0 = self.gstate.ctm.transform_point(x0, y0);
        let p1 = self.gstate.ctm.transform_point(x1, y0);
        let p2 = self.gstate.ctm.transform_point(x1, y1);
        let p3 = self.gstate.ctm.transform_point(x0, y1);
        let mut clip_path = PsPath::new();
        clip_path.segments.push(PathSegment::MoveTo(p0.0, p0.1));
        clip_path.segments.push(PathSegment::LineTo(p1.0, p1.1));
        clip_path.segments.push(PathSegment::LineTo(p2.0, p2.1));
        clip_path.segments.push(PathSegment::LineTo(p3.0, p3.1));
        clip_path.segments.push(PathSegment::ClosePath);
        self.display_list.push(DisplayElement::Clip {
            path: clip_path.clone(),
            params: ClipParams {
                fill_rule: FillRule::NonZeroWinding,
                ctm: Matrix::identity(),
                stroke_params: None,
            },
        });
        self.gstate
            .clip_stack
            .push((clip_path.clone(), FillRule::NonZeroWinding));
        self.gstate.clip_path = Some(clip_path);
        self.gstate.clip_path_version += 1;
    }

    /// Compute device-space bounding box from form BBox + current CTM.
    /// Compute the device-space bounding box of the current gstate's
    /// clip path. Clip paths are stored in device coordinates, so this
    /// is just `path_bbox(clip_path)`. Returns `None` when no clip path
    /// is active.
    fn current_clip_bbox(&self) -> Option<[f64; 4]> {
        let path = self.gstate.clip_path.as_ref()?;
        let mut x_min = f64::INFINITY;
        let mut y_min = f64::INFINITY;
        let mut x_max = f64::NEG_INFINITY;
        let mut y_max = f64::NEG_INFINITY;
        for seg in &path.segments {
            let pts: &[(f64, f64)] = match seg {
                PathSegment::MoveTo(x, y) | PathSegment::LineTo(x, y) => &[(*x, *y)],
                PathSegment::CurveTo {
                    x1,
                    y1,
                    x2,
                    y2,
                    x3,
                    y3,
                } => &[(*x1, *y1), (*x2, *y2), (*x3, *y3)][..],
                PathSegment::ClosePath => &[],
            };
            for (x, y) in pts {
                x_min = x_min.min(*x);
                y_min = y_min.min(*y);
                x_max = x_max.max(*x);
                y_max = y_max.max(*y);
            }
        }
        if x_min.is_finite() && x_min < x_max && y_min < y_max {
            Some([x_min, y_min, x_max, y_max])
        } else {
            None
        }
    }

    fn compute_device_bbox(&self, bbox: Option<(f64, f64, f64, f64)>) -> [f64; 4] {
        let Some((x0, y0, x1, y1)) = bbox else {
            // No BBox — use large sentinel
            return [0.0, 0.0, 1e9, 1e9];
        };
        let corners = [
            self.gstate.ctm.transform_point(x0, y0),
            self.gstate.ctm.transform_point(x1, y0),
            self.gstate.ctm.transform_point(x0, y1),
            self.gstate.ctm.transform_point(x1, y1),
        ];
        let mut min_x = f64::INFINITY;
        let mut min_y = f64::INFINITY;
        let mut max_x = f64::NEG_INFINITY;
        let mut max_y = f64::NEG_INFINITY;
        for (cx, cy) in &corners {
            min_x = min_x.min(*cx);
            min_y = min_y.min(*cy);
            max_x = max_x.max(*cx);
            max_y = max_y.max(*cy);
        }
        [min_x, min_y, max_x, max_y]
    }

    /// Handle inline image (BI ... ID ... EI).
    fn handle_inline_image(&mut self, lexer: &mut Lexer) -> Result<(), PdfError> {
        // Parse image dict (abbreviated keys)
        let mut dict = PdfDict::new();
        loop {
            let tok = lexer.next_token()?;
            match tok {
                Token::Keyword(ref kw) if kw == b"ID" => break,
                Token::Eof => return Ok(()),
                Token::Name(key) => {
                    let expanded_key = expand_inline_key(&key);
                    let val_tok = lexer.next_token()?;
                    let val = match val_tok {
                        Token::Int(n) => PdfObj::Int(n),
                        Token::Real(f) => PdfObj::Real(f),
                        Token::Name(n) => PdfObj::Name(expand_inline_value(&n)),
                        Token::Bool(b) => PdfObj::Bool(b),
                        Token::LitString(s) | Token::HexString(s) => PdfObj::Str(s),
                        Token::ArrayBegin => {
                            let arr = Self::parse_inline_array(lexer)?;
                            PdfObj::Array(arr)
                        }
                        Token::DictBegin => crate::lexer::parse_dict_body(lexer)
                            .map(PdfObj::Dict)
                            .unwrap_or(PdfObj::Null),
                        _ => PdfObj::Null,
                    };
                    // First occurrence wins: when both abbreviated (/W) and full
                    // (/Width) forms are present, the first one takes precedence.
                    if dict.get(&expanded_key).is_none() {
                        dict.insert(expanded_key, val);
                    }
                }
                _ => {}
            }
        }

        // Skip single whitespace byte after ID.
        // Treat \r\n as a single EOL delimiter (many PDF generators emit
        // ID\r\n before the image data).
        let data = lexer.data();
        let mut pos = lexer.pos();
        if pos < data.len() {
            if data[pos] == b'\r' {
                pos += 1;
                if pos < data.len() && data[pos] == b'\n' {
                    pos += 1;
                }
            } else if data[pos] == b' ' || data[pos] == b'\n' {
                pos += 1;
            }
        }

        // Read image data until EI
        let width = dict.get_int(b"Width").unwrap_or(0) as u32;
        let height = dict.get_int(b"Height").unwrap_or(0) as u32;
        let is_image_mask = matches!(dict.get(b"ImageMask"), Some(PdfObj::Bool(true)));
        let bpc = if is_image_mask {
            1
        } else {
            dict.get_int(b"BitsPerComponent").unwrap_or(8) as u32
        };

        let has_filter = dict.get(b"Filter").is_some() || dict.get(b"F").is_some();

        // Check if the outermost filter is ASCII85 — its data ends with `~>`,
        // which is a reliable boundary marker (unlike scanning for `\nEI` which
        // can match false positives inside ASCII85-encoded binary data).
        let outermost_is_ascii85 = dict
            .get(b"Filter")
            .or_else(|| dict.get(b"F"))
            .map(|f| match f {
                PdfObj::Name(n) => n == b"ASCII85Decode" || n == b"A85",
                PdfObj::Array(arr) => arr
                    .first()
                    .and_then(|o| o.as_name())
                    .map(|n| n == b"ASCII85Decode" || n == b"A85")
                    .unwrap_or(false),
                _ => false,
            })
            .unwrap_or(false);

        let resolved_cs = if is_image_mask {
            None
        } else if let Some(cs_obj) = dict.get(b"ColorSpace") {
            // For inline images, the CS value may be a resource name (e.g. /R35)
            // that needs lookup in the page's ColorSpace resources.
            let cs_resolved = if let PdfObj::Name(name) = cs_obj {
                // Try the cached index first, then fall back to resolving the
                // ColorSpace resource sub-dict directly.
                let from_cache = self
                    .cs_index
                    .as_ref()
                    .and_then(|idx| idx.get(name.as_slice()).cloned());
                let res_obj = from_cache.or_else(|| {
                    self.resolve_resource_subdict(b"ColorSpace")
                        .and_then(|d| d.get(name).cloned())
                });
                if let Some(ref obj) = res_obj {
                    resolve_color_space_obj(obj, self.resolver)
                } else {
                    resolve_color_space_obj(cs_obj, self.resolver)
                }
            } else {
                resolve_color_space_obj(cs_obj, self.resolver)
            };
            match cs_resolved {
                Ok(resolved) => Some(resolved),
                Err(_) => Some(ResolvedColorSpace::DeviceGray),
            }
        } else {
            Some(ResolvedColorSpace::DeviceGray)
        };
        let n_components = resolved_cs
            .as_ref()
            .map(|cs| cs.num_components() as u32)
            .unwrap_or(1);

        // Calculate expected uncompressed data length (for EI boundary search)
        let row_bits = width * n_components.max(1) * bpc;
        let row_bytes = row_bits.div_ceil(8);
        let expected_len = (row_bytes * height) as usize;

        // Find EI boundary — look for whitespace + "EI" + delimiter/EOF.
        // For compressed data (CCITT, Flate, etc.), the compressed data is smaller
        // than the uncompressed size, so we must search from the start of data.
        let start = pos;
        let search_from = if has_filter {
            start
        } else {
            start + expected_len
        };
        // First try: check for "EI" at/near the expected position (some PDFs omit
        // the whitespace before EI that the spec requires).
        let mut end = search_from;
        let mut found_no_ws = false;
        if !has_filter {
            // Check at expected_len-2, expected_len-1, and expected_len for "EI" without leading ws
            for offset in [
                expected_len.saturating_sub(2),
                expected_len.saturating_sub(1),
                expected_len,
            ] {
                let p = start + offset;
                if p + 1 < data.len()
                    && data[p] == b'E'
                    && data[p + 1] == b'I'
                    && (p + 2 >= data.len() || is_delimiter_or_ws(data[p + 2]))
                {
                    end = p;
                    found_no_ws = true;
                    break;
                }
            }
        }
        if !found_no_ws {
            if outermost_is_ascii85 {
                // ASCII85 data ends with `~>`. Search for that first, then find EI after it.
                // This avoids false-positive `\nEI` matches inside the ASCII85 data.
                let mut found_a85_end = false;
                let mut scan = search_from;
                while scan + 1 < data.len() {
                    if data[scan] == b'~' {
                        if data[scan + 1] == b'>' {
                            // Standard `~>` end-of-data marker
                            end = scan + 2;
                        } else if is_whitespace_byte(data[scan + 1]) {
                            // Malformed: `~` followed by whitespace (missing `>`)
                            // Accept if `EI` follows shortly after.
                            let mut probe = scan + 1;
                            while probe < data.len() && is_whitespace_byte(data[probe]) {
                                probe += 1;
                            }
                            if probe + 1 < data.len()
                                && data[probe] == b'E'
                                && data[probe + 1] == b'I'
                            {
                                end = scan + 1;
                            } else {
                                scan += 1;
                                continue;
                            }
                        } else {
                            scan += 1;
                            continue;
                        }
                        while end < data.len() && is_whitespace_byte(data[end]) {
                            end += 1;
                        }
                        // `end` should now point at 'E' of "EI"
                        found_a85_end = true;
                        found_no_ws = true;
                        break;
                    }
                    scan += 1;
                }
                if !found_a85_end {
                    // No `~>` found — fall back to standard search
                    while end + 2 < data.len() {
                        if is_whitespace_byte(data[end])
                            && data[end + 1] == b'E'
                            && data[end + 2] == b'I'
                            && (end + 3 >= data.len() || is_delimiter_or_ws(data[end + 3]))
                        {
                            break;
                        }
                        end += 1;
                    }
                }
            } else {
                while end + 2 < data.len() {
                    if is_whitespace_byte(data[end])
                        && data[end + 1] == b'E'
                        && data[end + 2] == b'I'
                        && (end + 3 >= data.len() || is_delimiter_or_ws(data[end + 3]))
                    {
                        break;
                    }
                    end += 1;
                }
            }
        }

        let sample_data = data[start..end.min(data.len())].to_vec();
        // Skip past EI: "EI" is 2 bytes, plus trailing whitespace/delimiter
        let skip_past = if found_no_ws {
            // EI at `end`, skip "EI" + 1 trailing byte
            (end + 3).min(data.len())
        } else {
            // ws+EI at `end`, skip ws+"EI" + 1 trailing byte
            (end + 4).min(data.len())
        };
        lexer.set_pos(skip_past);

        // Apply filters if present
        let sample_data = if has_filter {
            match crate::filters::parse_filters(&dict, Some(self.resolver)) {
                Ok((filters, parms)) if !filters.is_empty() => {
                    crate::filters::decode_stream(&sample_data, &filters, &parms, None)
                        .unwrap_or(sample_data)
                }
                _ => sample_data,
            }
        } else {
            sample_data
        };

        // Build color space for display list
        let polarity = if is_image_mask {
            if let Some(arr) = dict.get_array(b"Decode") {
                let vals: Vec<f64> = arr.iter().filter_map(|o| o.as_f64()).collect();
                vals.len() >= 2 && vals[0] > 0.5
            } else {
                false
            }
        } else {
            false
        };

        let image_matrix =
            Matrix::new(width as f64, 0.0, 0.0, -(height as f64), 0.0, height as f64);

        // Imagemask with shading pattern fill: use SoftMasked to clip shading to mask shape
        if is_image_mask && self.gstate.fill_shading_pattern.is_some() {
            let shading_box = self.gstate.fill_shading_pattern.clone().unwrap();

            // Convert 1-bit imagemask to 8-bit grayscale for luminosity soft mask
            // (white=opaque where painted, black=transparent)
            let row_bytes = width.div_ceil(8);
            let mut gray = vec![0u8; (width * height) as usize];
            for y in 0..height {
                for x in 0..width {
                    let byte_idx = (y * row_bytes + x / 8) as usize;
                    let bit_idx = 7 - (x % 8);
                    let bit = if byte_idx < sample_data.len() {
                        (sample_data[byte_idx] >> bit_idx) & 1
                    } else {
                        0
                    };
                    // Default Decode [0 1]: bit=0 → painted (opaque=255)
                    // Inverted [1 0]:      bit=1 → painted (opaque=255)
                    let painted = if polarity { bit == 1 } else { bit == 0 };
                    gray[(y * width + x) as usize] = if painted { 255 } else { 0 };
                }
            }

            // Mask display list: the imagemask as a grayscale image
            let mut mask_dl = DisplayList::new();
            mask_dl.push(DisplayElement::Image {
                sample_data: Arc::new(gray),
                params: ImageParams {
                    width,
                    height,
                    color_space: ImageColorSpace::DeviceGray,
                    bits_per_component: 8,
                    ctm: self.gstate.ctm,
                    image_matrix,
                    interpolate: false,
                    mask_color: None,
                    alpha: 1.0,
                    blend_mode: 0,
                    overprint: false,
                    overprint_mode: 0,
                    opm_paired: false,
                    painted_channels: 0,
                    alpha_is_shape: false,
                    rendering_intent: 0,
                },
            });

            // Content display list: the shading pattern
            let mut content_dl = DisplayList::new();
            for elem in shading_box.0.elements() {
                content_dl.push(elem.clone());
            }

            // Compute device-space bbox of the image
            let corners = [
                self.gstate.ctm.transform_point(0.0, 0.0),
                self.gstate.ctm.transform_point(width as f64, 0.0),
                self.gstate.ctm.transform_point(0.0, height as f64),
                self.gstate.ctm.transform_point(width as f64, height as f64),
            ];
            let x_min = corners.iter().map(|c| c.0).fold(f64::INFINITY, f64::min);
            let y_min = corners.iter().map(|c| c.1).fold(f64::INFINITY, f64::min);
            let x_max = corners
                .iter()
                .map(|c| c.0)
                .fold(f64::NEG_INFINITY, f64::max);
            let y_max = corners
                .iter()
                .map(|c| c.1)
                .fold(f64::NEG_INFINITY, f64::max);

            let parent_clip_bbox = self.current_clip_bbox();
            self.display_list.push(DisplayElement::SoftMasked {
                mask: mask_dl,
                content: content_dl,
                params: SoftMaskParams {
                    subtype: SoftMaskSubtype::Luminosity,
                    bbox: [x_min, y_min, x_max, y_max],
                    backdrop_color: None,
                    transfer_invert: false,
                    has_nested_mask_scope: false,
                    parent_clip_bbox,
                },
                mask_cache: Arc::new(Mutex::new(None)),
            });
            return Ok(());
        }

        let color_space = if is_image_mask {
            ImageColorSpace::Mask {
                color: self.gstate.fill_color.clone(),
                polarity,
                spot_color: self.gstate.fill_spot_color.clone(),
            }
        } else {
            to_image_color_space(resolved_cs.as_ref().unwrap())
        };

        // Expand bits if needed (but NOT for image masks — keep raw 1-bit packed data)
        let is_indexed = matches!(&color_space, ImageColorSpace::Indexed { .. });
        let sample_data = if !is_image_mask && bpc != 8 && bpc != 0 {
            expand_bits_to_bytes(&sample_data, bpc, width, height, n_components, is_indexed)
        } else {
            sample_data
        };

        // PDF/X CMYK group: route DeviceGray / Separation-with-gray-alt /
        // DeviceN-with-gray-alt images through the K plate so they composite
        // equivalently to DeviceCMYK 0/0/0/(1−g).
        let (color_space, sample_data) = if !is_image_mask {
            self.cmyk_group_promote_image(color_space, sample_data, width, height)
        } else {
            (color_space, sample_data)
        };

        // Register ICC profile with the cache so the rasterizer can find it
        // by hash.  Color conversion itself is deferred to samples_to_rgba().
        if !is_image_mask {
            if let Some(ref rcs) = resolved_cs {
                register_icc_profile(rcs, &mut self.icc_cache);
            }
        }

        self.display_list.push(DisplayElement::Image {
            sample_data: Arc::new(sample_data),
            params: ImageParams {
                width,
                height,
                color_space,
                bits_per_component: 8,
                ctm: self.gstate.ctm,
                image_matrix,
                interpolate: false,
                mask_color: None,
                alpha: self.gstate.fill_alpha,
                blend_mode: self.gstate.blend_mode,
                overprint: self.gstate.overprint,
                overprint_mode: self.gstate.overprint_mode,
                opm_paired: self.gstate.opm_paired,
                painted_channels: resolved_cs
                    .as_ref()
                    .map(painted_channels_for_cs)
                    .unwrap_or(self.gstate.fill_painted_channels),
                alpha_is_shape: self.gstate.alpha_is_shape,
                rendering_intent: 0,
            },
        });

        Ok(())
    }

    /// Apply ExtGState dictionary entries.
    fn apply_ext_gstate(&mut self, name: &[u8]) -> Result<(), PdfError> {
        let ext_dict = self
            .resolve_resource_subdict(b"ExtGState")
            .ok_or(PdfError::Other("no ExtGState resources".into()))?;
        let gs_ref = ext_dict.get(name).ok_or_else(|| {
            PdfError::Other(format!(
                "ExtGState /{} not found",
                String::from_utf8_lossy(name)
            ))
        })?;
        let gs_obj = self.resolver.deref(gs_ref)?;
        let gs_dict = gs_obj
            .as_dict()
            .ok_or(PdfError::Other("ExtGState is not a dict".into()))?;

        // Apply known keys
        if let Some(lw) = gs_dict.get_f64(b"LW") {
            self.gstate.line_width = lw;
        }
        if let Some(lc) = gs_dict.get_int(b"LC")
            && let Some(cap) = LineCap::from_i32(lc as i32)
        {
            self.gstate.line_cap = cap;
        }
        if let Some(lj) = gs_dict.get_int(b"LJ")
            && let Some(join) = LineJoin::from_i32(lj as i32)
        {
            self.gstate.line_join = join;
        }
        if let Some(ml) = gs_dict.get_f64(b"ML") {
            self.gstate.miter_limit = ml;
        }
        if let Some(fl) = gs_dict.get_f64(b"FL") {
            self.gstate.flatness = fl;
        }
        if let Some(PdfObj::Bool(sa)) = gs_dict.get(b"SA") {
            self.gstate.stroke_adjust = *sa;
        }
        // Always parse OPM — it affects whether CMYK all-zero is transparent,
        // which is needed even without full overprint simulation.
        let has_opm = gs_dict.get(b"OPM").is_some();
        if let Some(opm) = gs_dict.get_int(b"OPM") {
            self.gstate.overprint_mode = opm as i32;
        }
        let has_op_flag = gs_dict.get(b"OP").is_some() || gs_dict.get(b"op").is_some();
        if self.overprint_enabled {
            if let Some(PdfObj::Bool(op)) = gs_dict.get(b"OP") {
                self.gstate.overprint = *op;
                // OP also sets stroke overprint
                self.gstate.overprint_stroke = *op;
            }
            if let Some(PdfObj::Bool(op)) = gs_dict.get(b"op") {
                self.gstate.overprint = *op;
            }
        }
        // Track whether the current ExtGState signals "strict overprint",
        // meaning the strict OPM-1 "zero-source preserves backdrop" rule
        // applies. Two patterns count as a strict signal:
        //   1. /OPM together with /op|/OP in the same dict (Adobe Illustrator
        //      asserts both when emitting overprint).
        //   2. /OP and /op together in the same dict — legacy "old-style"
        //      overprint that drove both stroke and fill, used by GWG 12.0
        //      White Overprint where /GS6 sets `/OP true /op true`.
        // An /op set in isolation, with OPM merely inherited (e.g. 2495.pdf
        // page 5 page-icon: /R11 sets /OPM 1, /R20 sets only /op), falls
        // back to legacy "zero = knockout" semantics so `0 0 0 0 k` paints
        // still act as a white knockout.
        let has_op_upper = gs_dict.get(b"OP").is_some();
        let has_op_lower = gs_dict.get(b"op").is_some();
        let strict_signal = (has_opm && has_op_flag) || (has_op_upper && has_op_lower);
        if strict_signal {
            self.gstate.opm_paired = true;
        } else if has_opm || has_op_flag {
            self.gstate.opm_paired = false;
        }
        if let Some(ca) = gs_dict.get_f64(b"CA") {
            self.gstate.stroke_alpha = ca;
        }
        if let Some(ca) = gs_dict.get_f64(b"ca") {
            self.gstate.fill_alpha = ca;
        }
        if let Some(b) = gs_dict.get_bool(b"AIS") {
            self.gstate.alpha_is_shape = b;
        }
        if let Some(b) = gs_dict.get_bool(b"TK") {
            self.gstate.text_knockout = b;
        }
        // Rendering intent — feeds into the per-intent ICC chain dispatch.
        if let Some(PdfObj::Name(ri)) = gs_dict.get(b"RI") {
            self.gstate.rendering_intent = match ri.as_slice() {
                b"Perceptual" => 0,
                b"RelativeColorimetric" => 1,
                b"Saturation" => 2,
                b"AbsoluteColorimetric" => 3,
                _ => 0,
            };
        }

        // Blend mode
        if let Some(bm) = gs_dict.get(b"BM") {
            let bm = self.resolver.deref(bm).unwrap_or_else(|_| bm.clone());
            match &bm {
                PdfObj::Name(name) => {
                    self.gstate.blend_mode = blend_mode_from_name(name);
                }
                PdfObj::Array(arr) => {
                    for obj in arr {
                        if let PdfObj::Name(name) = obj {
                            let mode = blend_mode_from_name(name);
                            if mode != 0 || name.as_slice() == b"Normal" {
                                self.gstate.blend_mode = mode;
                                break;
                            }
                        }
                    }
                }
                _ => {}
            }
        }

        // Dash pattern
        if let Some(d_arr) = gs_dict.get_array(b"D")
            && d_arr.len() == 2
            && let (Some(arr), Some(offset)) = (d_arr[0].as_array(), d_arr[1].as_f64())
        {
            let array: Vec<f64> = arr.iter().filter_map(|o| o.as_f64()).collect();
            self.gstate.dash_pattern = DashPattern { array, offset };
        }

        // Font — array [font_ref size] sets both font and size
        if let Some(font_arr) = gs_dict.get_array(b"Font")
            && font_arr.len() == 2
            && let Some(size) = font_arr[1].as_f64()
        {
            self.gstate.font_size = size;
            // Resolve the font object from the first array element
            let font_ref = &font_arr[0];
            // Use object number as cache key, or a fallback synthetic name
            let cache_key = if let PdfObj::Ref(obj_num, _) = font_ref {
                format!("__gs_font_{obj_num}").into_bytes()
            } else {
                b"__gs_font_inline".to_vec()
            };
            if let Some(cached) = self.font_cache.get(&cache_key) {
                self.current_font = Some(Arc::clone(cached));
            } else {
                match font::resolve_font(self.resolver, font_ref, self.font_provider.as_ref()) {
                    Ok(font) => {
                        let arc = Arc::new(font);
                        self.font_cache.insert(cache_key, Arc::clone(&arc));
                        self.current_font = Some(arc);
                    }
                    Err(e) => {
                        eprintln!("warning: ExtGState Font: {e}");
                    }
                }
            }
        }

        // Transfer function: TR2 takes priority over TR
        if let Some(tr_obj) = gs_dict.get(b"TR2").or_else(|| gs_dict.get(b"TR")) {
            self.gstate.transfer = self.parse_transfer_function(tr_obj)?;
        }

        // Soft mask
        if let Some(smask_obj) = gs_dict.get(b"SMask") {
            let smask_obj = self.resolver.deref(smask_obj)?;
            match &smask_obj {
                PdfObj::Name(n) if n.as_slice() == b"None" => {
                    self.flush_soft_mask();
                    self.gstate.soft_mask = None;
                }
                PdfObj::Dict(d) => {
                    self.flush_soft_mask();
                    match self.resolve_soft_mask(d) {
                        Ok(sm) => {
                            let start_index = self.display_list.len();
                            self.gstate.soft_mask = Some(sm.clone());
                            self.gstate.smask_gen += 1;
                            self.soft_mask_scope = Some(SoftMaskScope {
                                start_index,
                                mask: sm,
                            });
                        }
                        Err(e) => {
                            eprintln!("warning: SMask resolve error: {}", e);
                        }
                    }
                }
                _ => {}
            }
        }

        Ok(())
    }

    /// Flush the current soft mask scope: wrap accumulated elements in SoftMasked.
    fn flush_soft_mask(&mut self) {
        if let Some(scope) = self.soft_mask_scope.take()
            && self.display_list.len() > scope.start_index
        {
            let content = self.display_list.split_off(scope.start_index);

            // Skip conditions:
            //
            // 1. The mask display list is empty: there is no mask raster
            //    to compute, so the SoftMasked element would have nothing
            //    to do — emit content directly.
            //
            // 2. (5795.pdf-style escape hatch) The mask form's bbox does
            //    not have *substantial* overlap with the content's painted
            //    area AND the backdrop is black. In this case the mask, if
            //    honored literally, would multiply most content pixels by
            //    0 (the BC fallback) and effectively erase the content.
            //    Both Ghostscript and Poppler short-circuit this and render
            //    the content as if no mask were present. We match that for:
            //
            //    - 5795.pdf: botanical background image. The mask `/G` form
            //      bbox sits at PDF x=[-767.7, 0.29] (essentially all
            //      negative-x). The content image is at PDF x=[0, 768].
            //      The bboxes touch only in the [0, 0.29 pt] sliver — no
            //      substantial overlap.
            //    - 907.pdf p24: gradient callout arrows. The SMask `/G`
            //      form bbox is at PDF y=[-155.6, -52.4] (negative-y, off
            //      the bottom of the page). The content image is at PDF
            //      y=[423, 501] — disjoint from the mask form bbox.
            //
            //    The CRITICAL distinction from 5296.pdf's /GS29 + /Fm30
            //    bug is that in 5296 the mask form's bbox at PDF
            //    x=[-519, -8] overlaps the content rectangle's bbox at
            //    PDF x=[-390, 121] across ~382 pt of x. The mask is
            //    *meant* to apply to the content — the visible portion of
            //    the content (x=[0, 121]) just falls outside the mask's
            //    spatial extent and should be erased by the BC=0 fallback.
            //
            //    The threshold of 2 device pt in both dimensions matches
            //    the original `mask_has_meaningful_overlap` threshold but
            //    measures against the content bbox (not the parent clip
            //    bbox), which is what actually distinguishes the two
            //    cases.
            let content_bbox = self.content_paint_bbox(&content);
            let drop_shadow_skip = scope.mask.backdrop_color == Some([0.0, 0.0, 0.0])
                && content_bbox
                    .map(|c| !bboxes_overlap_substantially(&c, &scope.mask.bbox, 2.0))
                    .unwrap_or(false);
            let skip = scope.mask.mask_list.is_empty() || drop_shadow_skip;
            if skip {
                for elem in content.into_elements() {
                    self.display_list.push(elem);
                }
            } else {
                // Collect Clip/InitClip elements to replay after SoftMasked.
                // The mask scope may capture clip operations that were established
                // in gsave levels that extend beyond the scope — these must remain
                // in the main display list to affect subsequent rendering.
                let clip_replay: Vec<DisplayElement> = content
                    .elements()
                    .iter()
                    .filter(|e| matches!(e, DisplayElement::Clip { .. } | DisplayElement::InitClip))
                    .cloned()
                    .collect();
                let parent_clip_bbox = self.current_clip_bbox();
                self.display_list.push(DisplayElement::SoftMasked {
                    mask: scope.mask.mask_list,
                    content,
                    params: SoftMaskParams {
                        subtype: scope.mask.subtype,
                        bbox: scope.mask.bbox,
                        backdrop_color: scope.mask.backdrop_color,
                        transfer_invert: scope.mask.transfer_invert,
                        has_nested_mask_scope: scope.mask.has_nested_mask_scope,
                        parent_clip_bbox,
                    },
                    mask_cache: Arc::new(Mutex::new(None)),
                });
                for elem in clip_replay {
                    self.display_list.push(elem);
                }
            }
        }
    }

    /// Resolve the number of color components from a form XObject's /Group/CS.
    /// Both /Group and /CS may be indirect references.
    fn resolve_group_cs_comps(&self, form_dict: &PdfDict) -> usize {
        let cs_name_to_comps = |cs: &[u8]| -> usize {
            match cs {
                b"DeviceGray" => 1,
                b"DeviceRGB" => 3,
                b"DeviceCMYK" => 4,
                _ => 0,
            }
        };

        let grp_obj = match form_dict.get(b"Group") {
            Some(obj) => obj,
            None => return 0,
        };

        // Get the Group dict — may be inline or indirect
        let resolved_grp;
        let grp = if let Some(d) = grp_obj.as_dict() {
            d
        } else if let Ok(r) = self.resolver.deref(grp_obj) {
            resolved_grp = r;
            match resolved_grp.as_dict() {
                Some(d) => d,
                None => return 0,
            }
        } else {
            return 0;
        };

        // Get CS — may be inline name or indirect
        if let Some(cs) = grp.get_name(b"CS") {
            return cs_name_to_comps(cs);
        }
        if let Some(cs_obj) = grp.get(b"CS") {
            if let Ok(cs_resolved) = self.resolver.deref(cs_obj) {
                if let Some(cs) = cs_resolved.as_name() {
                    return cs_name_to_comps(cs);
                }
            }
        }
        0
    }

    /// Compute the union of paint bounds for the elements in `content`.
    /// Returns `None` if no element contributes a bounded paint extent.
    ///
    /// This is a coarse estimate used by `flush_soft_mask` to decide
    /// whether the mask form's bbox overlaps the content. Only the most
    /// common element kinds are inspected (Fill, Stroke, Image, Group,
    /// SoftMasked, PatternFill); shading elements and text are treated
    /// as contributing no bound (we conservatively skip them, which
    /// for the drop-shadow-skip heuristic means we'll trust the result
    /// from the other elements present).
    fn content_paint_bbox(&self, content: &DisplayList) -> Option<[f64; 4]> {
        let mut x_min = f64::INFINITY;
        let mut y_min = f64::INFINITY;
        let mut x_max = f64::NEG_INFINITY;
        let mut y_max = f64::NEG_INFINITY;
        let mut grow = |bx: [f64; 4]| {
            x_min = x_min.min(bx[0].min(bx[2]));
            y_min = y_min.min(bx[1].min(bx[3]));
            x_max = x_max.max(bx[0].max(bx[2]));
            y_max = y_max.max(bx[1].max(bx[3]));
        };
        for elem in content.elements() {
            match elem {
                DisplayElement::Fill { path, .. }
                | DisplayElement::Stroke { path, .. }
                | DisplayElement::Clip { path, .. } => {
                    let mut px_min = f64::INFINITY;
                    let mut py_min = f64::INFINITY;
                    let mut px_max = f64::NEG_INFINITY;
                    let mut py_max = f64::NEG_INFINITY;
                    for seg in &path.segments {
                        let pts: &[(f64, f64)] = match seg {
                            PathSegment::MoveTo(x, y) | PathSegment::LineTo(x, y) => &[(*x, *y)],
                            PathSegment::CurveTo {
                                x1,
                                y1,
                                x2,
                                y2,
                                x3,
                                y3,
                            } => &[(*x1, *y1), (*x2, *y2), (*x3, *y3)][..],
                            PathSegment::ClosePath => &[],
                        };
                        for (x, y) in pts {
                            px_min = px_min.min(*x);
                            py_min = py_min.min(*y);
                            px_max = px_max.max(*x);
                            py_max = py_max.max(*y);
                        }
                    }
                    if px_min.is_finite() && px_min < px_max && py_min < py_max {
                        grow([px_min, py_min, px_max, py_max]);
                    }
                }
                DisplayElement::Image { params, .. } => {
                    // Image is drawn into the unit square mapped through
                    // params.ctm. Compute the four corner positions.
                    let ctm = &params.ctm;
                    let corners = [
                        ctm.transform_point(0.0, 0.0),
                        ctm.transform_point(1.0, 0.0),
                        ctm.transform_point(0.0, 1.0),
                        ctm.transform_point(1.0, 1.0),
                    ];
                    let mut ix_min = f64::INFINITY;
                    let mut iy_min = f64::INFINITY;
                    let mut ix_max = f64::NEG_INFINITY;
                    let mut iy_max = f64::NEG_INFINITY;
                    for (cx, cy) in &corners {
                        ix_min = ix_min.min(*cx);
                        iy_min = iy_min.min(*cy);
                        ix_max = ix_max.max(*cx);
                        iy_max = iy_max.max(*cy);
                    }
                    grow([ix_min, iy_min, ix_max, iy_max]);
                }
                DisplayElement::Group { params, .. } => {
                    grow(params.bbox);
                }
                DisplayElement::SoftMasked { params, .. } => {
                    grow(params.bbox);
                }
                _ => {} // Shadings, patterns, text — coarse estimate skips them.
            }
        }
        if x_min.is_finite() && x_min < x_max && y_min < y_max {
            Some([x_min, y_min, x_max, y_max])
        } else {
            None
        }
    }

    /// Resolve a soft mask dictionary into a SoftMask.
    fn resolve_soft_mask(&mut self, dict: &PdfDict) -> Result<graphics_state::SoftMask, PdfError> {
        // Parse /S (subtype): Alpha or Luminosity (default Luminosity)
        let subtype = match dict.get_name(b"S") {
            Some(b"Alpha") => SoftMaskSubtype::Alpha,
            _ => SoftMaskSubtype::Luminosity,
        };

        // Parse /G (Form XObject) — required
        let g_ref = dict
            .get(b"G")
            .ok_or_else(|| PdfError::Other("SMask missing /G".into()))?;
        let g_obj = self.resolver.deref(g_ref)?;
        let g_dict = g_obj
            .as_dict()
            .ok_or_else(|| PdfError::Other("SMask /G is not a dict".into()))?;

        // Get form BBox
        let bbox_tuple = if let Some(vals) = deref_num_array(self.resolver, g_dict, b"BBox") {
            if vals.len() == 4 {
                Some((vals[0], vals[1], vals[2], vals[3]))
            } else {
                None
            }
        } else {
            None
        };

        // Form matrix
        let form_matrix = if let Some(vals) = deref_num_array(self.resolver, g_dict, b"Matrix") {
            if vals.len() == 6 {
                Matrix::new(vals[0], vals[1], vals[2], vals[3], vals[4], vals[5])
            } else {
                Matrix::identity()
            }
        } else {
            Matrix::identity()
        };

        // Get form resources
        let form_resources = if let Some(res_obj) = g_dict.get(b"Resources") {
            match self.resolver.deref(res_obj)? {
                PdfObj::Dict(d) => d,
                _ => self.resources.clone(),
            }
        } else {
            self.resources.clone()
        };

        // Render the form into a display list
        let form_data = self.resolver.stream_data_from_obj(g_ref)?;

        // Save state and render (clear font cache — the mask form may have
        // different font resources with the same resource names as the parent)
        self.gstate_stack.push(self.gstate.clone());
        let saved_resources = std::mem::replace(&mut self.resources, form_resources);
        let saved_font_cache = std::mem::take(&mut self.font_cache);
        let saved_current_font2 = self.current_font.take();
        let saved_cs_index2 = self.cs_index.take();
        let saved_display_list = std::mem::replace(&mut self.display_list, DisplayList::new());
        let saved_scope = self.soft_mask_scope.take();
        let saved_content_stream_ctm = self.content_stream_ctm;
        let saved_mc_stack = std::mem::take(&mut self.mc_stack);

        // Apply form matrix to CTM
        self.gstate.ctm = self.gstate.ctm.concat(&form_matrix);
        // Update content_stream_ctm so shading patterns inside the mask form
        // use the form's coordinate system, not the parent's.
        self.content_stream_ctm = self.gstate.ctm;

        // Reset alpha and soft mask: the mask form is an independent rendering
        // context. Without this, the parent's ca/CA leak into the mask form
        // (e.g. ca=0.9 making mask form elements semi-transparent).
        self.gstate.fill_alpha = 1.0;
        self.gstate.stroke_alpha = 1.0;
        self.gstate.soft_mask = None;

        // Compute device-space bbox now, before interpret_stream modifies the
        // CTM via `cm` operators. The form BBox is in the form's coordinate
        // system (after form matrix), not the content's rotated space.
        let device_bbox = self.compute_device_bbox(bbox_tuple);

        // Clip to BBox
        if let Some((x0, y0, x1, y1)) = bbox_tuple {
            self.push_bbox_clip(x0, y0, x1, y1);
        }

        // Disable ICC CMYK conversion inside soft mask forms. ICC profiles
        // map 100% K to non-zero RGB (e.g. (44,41,42)), giving non-zero
        // luminosity where the mask should be opaque black. PLRM formulas
        // produce exact (0,0,0) for CMYK (0,0,0,1), yielding correct
        // luminosity = 0 for the mask.
        let saved_cmyk_hash = self.icc_cache.suspend_default_cmyk();
        // Suppress the DeviceGray-to-K-only promotion while parsing the SMask
        // form. The promotion produces a DeviceCMYK image whose ICC
        // conversion happens at render time (after the suspension above is
        // restored), so the parse-time suspend never sees it. Skipping the
        // promotion here keeps the SMask source's display list in its
        // original DeviceGray form, which the renderer paints gray-to-gray
        // without ICC — luminosity = g/255 exactly (regressed
        // `pdf_samples/2495.pdf`'s right-side SMask images).
        let saved_in_smask_form = self.in_smask_form;
        self.in_smask_form = true;

        let saved_nested_mask_flush_count = self.nested_mask_flush_count;
        self.depth += 1;
        let _ = self.interpret_stream(&form_data);
        self.depth -= 1;

        self.in_smask_form = saved_in_smask_form;
        self.icc_cache.restore_default_cmyk(saved_cmyk_hash);

        // Check if Q handlers flushed any gs-set nested soft mask scopes
        // during interpretation. This is tracked via a counter that's
        // incremented in op_big_q when smask_gen changes (NOT by image-level
        // SMasks or other SoftMasked element sources).
        let has_nested_mask_scope = self.nested_mask_flush_count > saved_nested_mask_flush_count;

        // Flush any soft mask scope opened inside the mask form
        self.flush_soft_mask();

        let mask_list = std::mem::replace(&mut self.display_list, saved_display_list);
        self.soft_mask_scope = saved_scope;
        self.content_stream_ctm = saved_content_stream_ctm;
        self.resources = saved_resources;
        self.font_cache = saved_font_cache;
        self.current_font = saved_current_font2;
        self.cs_index = saved_cs_index2;
        self.mc_stack = saved_mc_stack;
        if let Some(saved) = self.gstate_stack.pop() {
            self.gstate = saved;
        }

        // Parse /BC (backdrop color) — may be inline array or indirect reference.
        // BC is in the group's color space, so we check /G's /Group/CS to know
        // how many components to use (rather than guessing from array length).
        let group_n_comps = self.resolve_group_cs_comps(g_dict);

        let backdrop_color = if let Some(bc_obj) = dict.get(b"BC") {
            let bc_resolved = self.resolver.deref(bc_obj).ok();
            let bc_arr = bc_resolved
                .as_ref()
                .and_then(|o| o.as_array())
                .or_else(|| bc_obj.as_array());
            if let Some(arr) = bc_arr {
                let vals: Vec<f64> = arr.iter().filter_map(|o| o.as_f64()).collect();
                if group_n_comps == 1 && !vals.is_empty() {
                    // DeviceGray: first value is gray level
                    Some([vals[0], vals[0], vals[0]])
                } else if group_n_comps == 4 && vals.len() >= 4 {
                    // DeviceCMYK
                    let c = vals[0];
                    let m = vals[1];
                    let y = vals[2];
                    let k = vals[3];
                    Some([
                        (1.0 - c) * (1.0 - k),
                        (1.0 - m) * (1.0 - k),
                        (1.0 - y) * (1.0 - k),
                    ])
                } else if vals.len() >= 3 {
                    Some([vals[0], vals[1], vals[2]])
                } else if vals.len() == 1 {
                    Some([vals[0], vals[0], vals[0]])
                } else {
                    None
                }
            } else {
                None
            }
        } else {
            // No /BC specified: default is all zeros in the group color space.
            // For DeviceCMYK, [0,0,0,0] = no ink = white → RGB [1,1,1].
            // For DeviceRGB/Gray, [0,0,0] = black → RGB [0,0,0] (luminosity 0).
            if group_n_comps == 4 {
                Some([1.0, 1.0, 1.0])
            } else {
                None
            }
        };

        // Check for /TR (transfer function). The common case is {1 exch sub}
        // which inverts the mask values. Detect this and set a flag.
        // Check for /TR (transfer function). The common case is {1 exch sub}
        // which inverts the mask values. Detect this by reading the stream content.
        let transfer_invert = if let Some(tr_obj) = dict.get(b"TR") {
            if let Ok(tr_data) = self.resolver.stream_data_from_obj(tr_obj) {
                let trimmed: Vec<u8> = tr_data
                    .iter()
                    .copied()
                    .filter(|b| !b.is_ascii_whitespace())
                    .collect();
                let s = String::from_utf8_lossy(&trimmed);
                s.contains("exchsub")
            } else {
                false
            }
        } else {
            false
        };

        // When BC is specified and produces a non-zero luminosity value, the
        // soft mask extends beyond the form's BBox — the BC backdrop fills all
        // areas outside the form content. Expand the bbox to cover the entire
        // viewport so the renderer doesn't crop the mask to the form's BBox.
        let effective_bbox = if let Some(bc) = &backdrop_color {
            let bc_lum = 0.2126 * bc[0] + 0.7152 * bc[1] + 0.0722 * bc[2];
            let bc_byte = (bc_lum * 255.0 + 0.5) as u8;
            // After transfer inversion, the effective mask value is 255 - bc_byte.
            // If either the original or inverted value is non-zero, the mask has
            // effect outside the form BBox.
            let effective = if transfer_invert {
                255 - bc_byte
            } else {
                bc_byte
            };
            if effective > 0 {
                [0.0, 0.0, 1e9, 1e9]
            } else {
                device_bbox
            }
        } else {
            device_bbox
        };

        Ok(graphics_state::SoftMask {
            mask_list,
            subtype,
            bbox: effective_bbox,
            backdrop_color,
            transfer_invert,
            has_nested_mask_scope,
        })
    }

    /// Parse a TR/TR2 value into a TransferState.
    ///
    /// PDF spec: TR/TR2 can be a single function (applied to all channels),
    /// an array of 4 functions [R, G, B, Gray], or /Identity.
    fn parse_transfer_function(
        &self,
        obj: &PdfObj,
    ) -> Result<stet_graphics::device::TransferState, PdfError> {
        use crate::resources::function::PdfFunction;
        use stet_graphics::device::TransferState;

        let obj = self.resolver.deref(obj)?;

        // /Identity or /Default → no transfer
        if let Some(name) = obj.as_name()
            && (name == b"Identity" || name == b"Default")
        {
            return Ok(TransferState::default());
        }

        // Array of 4 functions [R, G, B, Gray]
        if let PdfObj::Array(arr) = &obj
            && arr.len() == 4
        {
            let mut tables: [Option<Arc<Vec<f64>>>; 4] = Default::default();
            for (i, fn_obj) in arr.iter().enumerate() {
                let fn_obj = self.resolver.deref(fn_obj)?;
                if let Some(name) = fn_obj.as_name()
                    && (name == b"Identity" || name == b"Default")
                {
                    continue; // None = identity
                }
                if let Ok(func) = PdfFunction::parse(&fn_obj, self.resolver) {
                    tables[i] = Some(Arc::new(sample_transfer_function(&func)));
                }
            }
            return Ok(TransferState {
                gray: None,
                color: Some(tables),
            });
        }

        // Single function → apply to all channels via gray
        if let Ok(func) = PdfFunction::parse(&obj, self.resolver) {
            let table = Arc::new(sample_transfer_function(&func));
            return Ok(TransferState {
                gray: Some(table),
                color: None,
            });
        }

        Ok(TransferState::default())
    }

    // === Shading operator ===

    fn op_sh(&mut self) -> Result<(), PdfError> {
        let name = self
            .operand_stack
            .last()
            .and_then(|o| o.as_name())
            .ok_or(PdfError::Other("sh: expected name".into()))?
            .to_vec();

        let shading_dict = self
            .resolve_resource_subdict(b"Shading")
            .ok_or(PdfError::Other("no Shading resources".into()))?;
        let sh_ref = shading_dict.get(&name).ok_or_else(|| {
            PdfError::Other(format!(
                "Shading /{} not found",
                String::from_utf8_lossy(&name)
            ))
        })?;
        let sh_ref_clone = sh_ref.clone();
        let sh_obj = self.resolver.deref(sh_ref)?;
        let sh_dict = sh_obj
            .as_dict()
            .ok_or(PdfError::Other("Shading is not a dict".into()))?;

        crate::resources::shading::handle_shading(
            &sh_ref_clone,
            sh_dict,
            &self.gstate,
            self.resolver,
            &mut self.display_list,
            &mut self.icc_cache,
        )
    }

    // === Pattern operators ===

    fn handle_pattern_fill(&mut self) -> Result<(), PdfError> {
        let name = self
            .operand_stack
            .last()
            .and_then(|o| o.as_name())
            .ok_or(PdfError::Other("pattern: expected name".into()))?
            .to_vec();

        // For uncolored patterns (PaintType 2), the scn operands include
        // underlying color components before the pattern name. Extract them
        // by resolving the underlying color space from the Pattern CS definition.
        self.extract_pattern_underlying_color(false)?;

        // Check PatternType before resolving — Type 2 (shading) needs different handling
        let pattern_dict = self
            .resolve_resource_subdict(b"Pattern")
            .ok_or(PdfError::Other("no Pattern resources".into()))?;
        let pat_ref = pattern_dict.get(&name).ok_or_else(|| {
            PdfError::Other(format!(
                "Pattern /{} not found",
                String::from_utf8_lossy(&name)
            ))
        })?;
        let pat_obj = self.resolver.deref(pat_ref)?;
        let pat_dict = pat_obj
            .as_dict()
            .ok_or(PdfError::Other("Pattern is not a dict".into()))?;
        let pattern_type = pat_dict.get_int(b"PatternType").unwrap_or(1) as i32;

        if pattern_type == 2 {
            let shading_dl = self.resolve_shading_pattern(pat_dict)?;
            self.gstate.fill_pattern = None;
            self.gstate.fill_shading_pattern = Some(Box::new(ShadingPatternDL(shading_dl)));
        } else {
            let pattern = self.resolve_pattern(&name)?;
            self.gstate.fill_shading_pattern = None;
            self.gstate.fill_pattern = Some(pattern);
        }
        Ok(())
    }

    fn handle_pattern_stroke(&mut self) -> Result<(), PdfError> {
        let name = self
            .operand_stack
            .last()
            .and_then(|o| o.as_name())
            .ok_or(PdfError::Other("pattern: expected name".into()))?
            .to_vec();

        // Extract underlying color components for uncolored patterns
        self.extract_pattern_underlying_color(true)?;

        // Check PatternType before resolving — Type 2 (shading) needs different handling
        let pattern_dict = self
            .resolve_resource_subdict(b"Pattern")
            .ok_or(PdfError::Other("no Pattern resources".into()))?;
        let pat_ref = pattern_dict.get(&name).ok_or_else(|| {
            PdfError::Other(format!(
                "Pattern /{} not found",
                String::from_utf8_lossy(&name)
            ))
        })?;
        let pat_obj = self.resolver.deref(pat_ref)?;
        let pat_dict = pat_obj
            .as_dict()
            .ok_or(PdfError::Other("Pattern is not a dict".into()))?;
        let pattern_type = pat_dict.get_int(b"PatternType").unwrap_or(1) as i32;

        if pattern_type == 2 {
            let shading_dl = self.resolve_shading_pattern(pat_dict)?;
            self.gstate.stroke_pattern = None;
            self.gstate.stroke_shading_pattern = Some(Box::new(ShadingPatternDL(shading_dl)));
        } else {
            let pattern = self.resolve_pattern(&name)?;
            self.gstate.stroke_shading_pattern = None;
            self.gstate.stroke_pattern = Some(pattern);
        }
        Ok(())
    }

    /// Extract underlying color components from the operand stack for Pattern
    /// color spaces with an underlying CS (e.g., `[/Pattern /DeviceRGB]`).
    /// For `scn` with an uncolored pattern, the operands are `c1 c2 ... /PatName`
    /// where c1..cn are the underlying color components.
    fn extract_pattern_underlying_color(&mut self, is_stroke: bool) -> Result<(), PdfError> {
        // Get the color space reference (fill or stroke)
        let cs_ref = if is_stroke {
            &self.gstate.stroke_color_space
        } else {
            &self.gstate.fill_color_space
        };
        let cs_name = match cs_ref {
            ColorSpaceRef::Named(n) => n.clone(),
            _ => return Ok(()),
        };

        // Look up the Pattern CS definition in resources to find the underlying CS.
        // Use the cached cs_index (built by resolve_cs_cached) for fast lookup,
        // falling back to the raw ColorSpace resource dict.
        let cs_obj_opt: Option<crate::objects::PdfObj> = self
            .cs_index
            .as_ref()
            .and_then(|idx| idx.get(cs_name.as_slice()).cloned())
            .or_else(|| {
                let cs_dict = self
                    .resources
                    .get(b"ColorSpace")
                    .and_then(|obj| match obj {
                        PdfObj::Dict(_) => Some(obj.as_dict().unwrap().clone()),
                        PdfObj::Ref(n, g) => self.resolver.resolve(*n, *g).ok()?.as_dict().cloned(),
                        _ => None,
                    })?;
                cs_dict.get(&cs_name).cloned()
            });
        let cs_obj = match cs_obj_opt {
            Some(obj) => obj.clone(),
            None => return Ok(()),
        };
        let cs_resolved = self.resolver.deref(&cs_obj)?;
        let arr = match &cs_resolved {
            PdfObj::Array(a) if a.len() >= 2 => a,
            _ => return Ok(()),
        };
        // Must be [/Pattern <underlying_cs>]
        if arr[0].as_name() != Some(b"Pattern") {
            return Ok(());
        }
        // Resolve the underlying color space
        let underlying_cs = color_space::resolve_color_space_obj(&arr[1], self.resolver)?;
        let n = underlying_cs.num_components();
        if n == 0 {
            return Ok(());
        }

        // The operand stack has: [... c1 c2 ... cn /PatName]
        // The pattern name is at the end; color components are before it.
        let stack_len = self.operand_stack.len();
        if stack_len < n + 1 {
            return Ok(()); // not enough operands
        }
        // Read n components from positions (stack_len - 1 - n) .. (stack_len - 1)
        let mut nums = Vec::with_capacity(n);
        let base = stack_len - 1 - n;
        for i in 0..n {
            nums.push(self.operand_stack[base + i].as_f64().unwrap_or(0.0));
        }
        let intent = self.gstate.rendering_intent;
        let color = color_space::components_to_device_color_icc_with_intent(
            &underlying_cs,
            &nums,
            Some(&mut self.icc_cache),
            intent,
        );
        if is_stroke {
            self.gstate.stroke_color = color;
        } else {
            self.gstate.fill_color = color;
        }
        Ok(())
    }

    fn resolve_pattern(&mut self, name: &[u8]) -> Result<TilingPattern, PdfError> {
        let pattern_dict = self
            .resolve_resource_subdict(b"Pattern")
            .ok_or(PdfError::Other("no Pattern resources".into()))?;
        let pat_ref = pattern_dict.get(name).ok_or_else(|| {
            PdfError::Other(format!(
                "Pattern /{} not found",
                String::from_utf8_lossy(name)
            ))
        })?;

        // Cache tiling patterns by indirect reference — ensures the same
        // pattern stream is interpreted only once (with the first caller's
        // graphics state), matching GhostScript's behaviour.
        if let PdfObj::Ref(obj_num, gen_num) = pat_ref {
            if let Some(cached) = self.pattern_cache.get(&(*obj_num, *gen_num)) {
                return Ok(cached.clone());
            }
        }

        let pat_ref_clone = pat_ref.clone();
        let pat_obj = self.resolver.deref(pat_ref)?;
        let pat_dict = pat_obj
            .as_dict()
            .ok_or(PdfError::Other("Pattern is not a dict".into()))?;

        let pattern_type = pat_dict.get_int(b"PatternType").unwrap_or(1) as i32;

        let result = match pattern_type {
            1 => self.resolve_tiling_pattern(&pat_ref_clone, pat_dict),
            _ => Err(PdfError::Other(format!(
                "Unsupported PatternType {pattern_type}"
            ))),
        }?;

        if let PdfObj::Ref(obj_num, gen_num) = pat_ref {
            self.pattern_cache
                .insert((*obj_num, *gen_num), result.clone());
        }

        Ok(result)
    }

    fn resolve_tiling_pattern(
        &mut self,
        pat_obj: &PdfObj,
        pat_dict: &PdfDict,
    ) -> Result<TilingPattern, PdfError> {
        if self.depth >= 20 {
            return Err(PdfError::Other("pattern recursion limit".into()));
        }
        let paint_type = pat_dict.get_int(b"PaintType").unwrap_or(1) as i32;

        let bbox = deref_num_array(self.resolver, pat_dict, b"BBox")
            .map(|v| {
                if v.len() >= 4 {
                    [v[0], v[1], v[2], v[3]]
                } else {
                    [0.0, 0.0, 1.0, 1.0]
                }
            })
            .unwrap_or([0.0, 0.0, 1.0, 1.0]);

        let x_step = pat_dict.get_f64(b"XStep").unwrap_or(bbox[2] - bbox[0]);
        let y_step = pat_dict.get_f64(b"YStep").unwrap_or(bbox[3] - bbox[1]);

        let pattern_matrix = deref_num_array(self.resolver, pat_dict, b"Matrix")
            .map(|v| {
                if v.len() >= 6 {
                    Matrix::new(v[0], v[1], v[2], v[3], v[4], v[5])
                } else {
                    Matrix::identity()
                }
            })
            .unwrap_or_else(Matrix::identity);

        let pattern_resources = if let Some(res_ref) = pat_dict.get(b"Resources") {
            match self.resolver.deref(res_ref)? {
                PdfObj::Dict(d) => d,
                _ => self.resources.clone(),
            }
        } else {
            self.resources.clone()
        };

        let pattern_data = self.resolver.stream_data_from_obj(pat_obj)?;

        // Compute the combined pattern matrix (pattern space → device space).
        // PDF pattern Matrix maps pattern space → the default coordinate system
        // of the parent content stream. Use content_stream_ctm so patterns inside
        // Form XObjects include the form's coordinate transform.
        let combined_matrix = self.content_stream_ctm.concat(&pattern_matrix);

        // Interpret pattern content stream with identity CTM, keeping tile
        // elements in pattern space.  The combined_matrix is stored in the
        // TilingPattern and applied per-element by the renderer (same approach
        // as PostScript op_makepattern).
        self.gstate_stack.push(self.gstate.clone());
        let saved_resources = std::mem::replace(&mut self.resources, pattern_resources);
        let saved_display_list = std::mem::take(&mut self.display_list);
        let saved_content_stream_ctm = self.content_stream_ctm;
        let saved_path = std::mem::take(&mut self.current_path);
        let saved_point = self.current_point.take();
        let saved_subpath = self.subpath_start.take();
        let saved_mc_stack = std::mem::take(&mut self.mc_stack);

        self.gstate.ctm = Matrix::identity();
        self.content_stream_ctm = Matrix::identity();
        self.gstate.clip_path = None;
        self.gstate.clip_path_version = 0;
        self.gstate.clip_stack.clear();
        // Clear parent patterns to prevent infinite recursion if the pattern
        // stream references the same pattern resource.
        self.gstate.fill_pattern = None;
        self.gstate.stroke_pattern = None;
        self.gstate.fill_shading_pattern = None;
        self.gstate.stroke_shading_pattern = None;
        // Reset text rendering mode so pattern tiles don't inherit
        // fill+stroke or other modes from the parent content stream.
        self.gstate.text_rendering_mode = 0;

        self.depth += 1;
        let _ = self.interpret_stream(&pattern_data);
        self.depth -= 1;

        // Flush any pending soft mask scope from the pattern stream
        self.flush_soft_mask();

        let tile_display_list = std::mem::replace(&mut self.display_list, saved_display_list);
        self.content_stream_ctm = saved_content_stream_ctm;
        self.resources = saved_resources;
        self.current_path = saved_path;
        self.current_point = saved_point;
        self.subpath_start = saved_subpath;
        self.mc_stack = saved_mc_stack;
        if let Some(saved) = self.gstate_stack.pop() {
            self.gstate = saved;
        }

        Ok(TilingPattern {
            tile: tile_display_list,
            bbox,
            x_step,
            y_step,
            pattern_matrix: combined_matrix,
            paint_type,
            pattern_id: 0,
            flip_tile_y: false,
        })
    }

    /// Resolve a PatternType 2 (shading pattern) by rendering the shading into
    /// a display list. The caller stores this and emits it at fill time,
    /// clipped to the fill path.
    fn resolve_shading_pattern(&mut self, pat_dict: &PdfDict) -> Result<DisplayList, PdfError> {
        let sh_ref = pat_dict
            .get(b"Shading")
            .ok_or(PdfError::Other("shading pattern missing /Shading".into()))?;
        let sh_ref_clone = sh_ref.clone();
        let sh_obj = self.resolver.deref(sh_ref)?;
        let sh_dict = sh_obj
            .as_dict()
            .ok_or(PdfError::Other("Shading is not a dict".into()))?;

        let pattern_matrix = deref_num_array(self.resolver, pat_dict, b"Matrix")
            .map(|v| {
                if v.len() >= 6 {
                    Matrix::new(v[0], v[1], v[2], v[3], v[4], v[5])
                } else {
                    Matrix::identity()
                }
            })
            .unwrap_or_else(Matrix::identity);

        // Render the shading into a temporary display list with pattern matrix
        // applied to the CTM so coordinates are in device space.
        // Use content_stream_ctm so that patterns inside Form XObjects include
        // the form's coordinate transform.
        //
        // Clear overprint while building the shading display list. The pattern
        // is resolved at `scn`/`SCN` time, but overprint should come from the
        // graphics state at paint time (when Tj/f/S executes). Capturing the
        // resolution-time overprint bakes a stale flag into the shading elements
        // — if the caller applies a different ExtGState between `scn` and the
        // paint operator, the shading would carry the wrong overprint state.
        // Setting overprint=false here is safe because paint-time code wraps
        // shading patterns in isolated groups, so overprint compositing does
        // not cross the group boundary.
        let combined_matrix = self.content_stream_ctm.concat(&pattern_matrix);
        let saved_ctm = self.gstate.ctm;
        let saved_overprint = self.gstate.overprint;
        let saved_overprint_stroke = self.gstate.overprint_stroke;
        self.gstate.ctm = combined_matrix;
        self.gstate.overprint = false;
        self.gstate.overprint_stroke = false;

        let mut shading_dl = DisplayList::new();
        let result = crate::resources::shading::handle_shading(
            &sh_ref_clone,
            sh_dict,
            &self.gstate,
            self.resolver,
            &mut shading_dl,
            &mut self.icc_cache,
        );
        self.gstate.ctm = saved_ctm;
        self.gstate.overprint = saved_overprint;
        self.gstate.overprint_stroke = saved_overprint_stroke;
        result?;
        Ok(shading_dl)
    }
}

/// Test whether two `[xmin, ymin, xmax, ymax]` rectangles overlap by at
/// least `min_extent` device units in BOTH dimensions. The `[f64; 4]`
/// slots are accepted in either ordering (we min/max the pair of x and y
/// components before testing).
///
/// Used by `flush_soft_mask` to discriminate "mask form is meaningfully
/// covering the content" (≥ min_extent in both axes) from "mask form is
/// only edge-touching the content" (< min_extent in at least one axis).
/// The latter case is treated as a no-op mask, matching the historical
/// Ghostscript behavior on PDFs like 5795.pdf where the mask form lives
/// in off-page coordinates and barely grazes the visible content.
fn bboxes_overlap_substantially(a: &[f64; 4], b: &[f64; 4], min_extent: f64) -> bool {
    let (ax0, ay0, ax1, ay1) = (
        a[0].min(a[2]),
        a[1].min(a[3]),
        a[0].max(a[2]),
        a[1].max(a[3]),
    );
    let (bx0, by0, bx1, by1) = (
        b[0].min(b[2]),
        b[1].min(b[3]),
        b[0].max(b[2]),
        b[1].max(b[3]),
    );
    let overlap_w = (ax1.min(bx1) - ax0.max(bx0)).max(0.0);
    let overlap_h = (ay1.min(by1) - ay0.max(by0)).max(0.0);
    overlap_w >= min_extent && overlap_h >= min_extent
}

fn path_device_bbox(path: &PsPath) -> [f64; 4] {
    let mut x_min = f64::INFINITY;
    let mut y_min = f64::INFINITY;
    let mut x_max = f64::NEG_INFINITY;
    let mut y_max = f64::NEG_INFINITY;
    let mut update = |x: f64, y: f64| {
        x_min = x_min.min(x);
        y_min = y_min.min(y);
        x_max = x_max.max(x);
        y_max = y_max.max(y);
    };
    for seg in &path.segments {
        match seg {
            PathSegment::MoveTo(x, y) | PathSegment::LineTo(x, y) => update(*x, *y),
            PathSegment::CurveTo {
                x1,
                y1,
                x2,
                y2,
                x3,
                y3,
            } => {
                update(*x1, *y1);
                update(*x2, *y2);
                update(*x3, *y3);
            }
            PathSegment::ClosePath => {}
        }
    }
    [x_min, y_min, x_max, y_max]
}

/// Convert a color space name to a ColorSpaceRef.
fn name_to_cs_ref(name: &[u8]) -> ColorSpaceRef {
    match name {
        b"DeviceGray" | b"G" => ColorSpaceRef::DeviceGray,
        b"DeviceRGB" | b"RGB" => ColorSpaceRef::DeviceRGB,
        b"DeviceCMYK" | b"CMYK" => ColorSpaceRef::DeviceCMYK,
        _ => ColorSpaceRef::Named(name.to_vec()),
    }
}

/// Expand abbreviated inline image key names.
fn expand_inline_key(key: &[u8]) -> Vec<u8> {
    match key {
        b"BPC" => b"BitsPerComponent".to_vec(),
        b"CS" => b"ColorSpace".to_vec(),
        b"D" => b"Decode".to_vec(),
        b"DP" => b"DecodeParms".to_vec(),
        b"F" => b"Filter".to_vec(),
        b"H" => b"Height".to_vec(),
        b"IM" => b"ImageMask".to_vec(),
        b"I" => b"Interpolate".to_vec(),
        b"W" => b"Width".to_vec(),
        _ => key.to_vec(),
    }
}

/// Expand abbreviated inline image value names.
fn expand_inline_value(name: &[u8]) -> Vec<u8> {
    match name {
        b"G" => b"DeviceGray".to_vec(),
        b"RGB" => b"DeviceRGB".to_vec(),
        b"CMYK" => b"DeviceCMYK".to_vec(),
        b"I" => b"Indexed".to_vec(),
        b"AHx" => b"ASCIIHexDecode".to_vec(),
        b"A85" => b"ASCII85Decode".to_vec(),
        b"LZW" => b"LZWDecode".to_vec(),
        b"Fl" => b"FlateDecode".to_vec(),
        b"RL" => b"RunLengthDecode".to_vec(),
        b"CCF" => b"CCITTFaxDecode".to_vec(),
        b"DCT" => b"DCTDecode".to_vec(),
        _ => name.to_vec(),
    }
}

/// Bilinear upsample of image data to target dimensions.
/// Used when an explicit mask is higher resolution than the image (MRC PDFs).
fn bilinear_upsample_image(
    data: &[u8],
    sw: u32,
    sh: u32,
    dw: u32,
    dh: u32,
    cs: &ImageColorSpace,
) -> Vec<u8> {
    let n = cs.num_components() as usize;
    if n == 0 || sw == 0 || sh == 0 || dw == 0 || dh == 0 {
        return data.to_vec();
    }
    let src_stride = sw as usize * n;
    let dst_stride = dw as usize * n;
    let mut out = vec![0u8; dst_stride * dh as usize];

    for dy in 0..dh as usize {
        let sy = (dy as f32 + 0.5) * sh as f32 / dh as f32 - 0.5;
        let sy0 = (sy.floor() as i32).clamp(0, sh as i32 - 1) as usize;
        let sy1 = (sy0 + 1).min(sh as usize - 1);
        let fy = sy - sy0 as f32;

        for dx in 0..dw as usize {
            let sx = (dx as f32 + 0.5) * sw as f32 / dw as f32 - 0.5;
            let sx0 = (sx.floor() as i32).clamp(0, sw as i32 - 1) as usize;
            let sx1 = (sx0 + 1).min(sw as usize - 1);
            let fx = sx - sx0 as f32;

            let w00 = (1.0 - fx) * (1.0 - fy);
            let w10 = fx * (1.0 - fy);
            let w01 = (1.0 - fx) * fy;
            let w11 = fx * fy;

            let i00 = sy0 * src_stride + sx0 * n;
            let i10 = sy0 * src_stride + sx1 * n;
            let i01 = sy1 * src_stride + sx0 * n;
            let i11 = sy1 * src_stride + sx1 * n;

            let di = dy * dst_stride + dx * n;
            for c in 0..n {
                let v = data[i00 + c] as f32 * w00
                    + data[i10 + c] as f32 * w10
                    + data[i01 + c] as f32 * w01
                    + data[i11 + c] as f32 * w11;
                out[di + c] = (v + 0.5).clamp(0.0, 255.0) as u8;
            }
        }
    }
    out
}

/// Expand image sample data from arbitrary BPC to 8-bit.
/// Merge image sample data with an SMask alpha channel into RGBA.
fn merge_rgb_with_smask(
    image_data: &[u8],
    smask_data: &[u8],
    color_space: &ImageColorSpace,
    width: u32,
    height: u32,
    icc: Option<&stet_graphics::icc::IccCache>,
) -> Vec<u8> {
    // For Indexed images, expand palette indices to RGB first
    if let ImageColorSpace::Indexed {
        base,
        hival,
        lookup,
    } = color_space
    {
        let n_base = base.num_components() as usize;
        let n_pixels = (width * height) as usize;
        let mut expanded = vec![0u8; n_pixels * n_base];
        for i in 0..n_pixels {
            let idx = image_data.get(i).copied().unwrap_or(0) as usize;
            let idx = idx.min(*hival as usize);
            let offset = idx * n_base;
            for c in 0..n_base {
                expanded[i * n_base + c] = lookup.get(offset + c).copied().unwrap_or(0);
            }
        }
        return merge_rgb_with_smask(&expanded, smask_data, base, width, height, icc);
    }

    // For Separation/DeviceN, convert through tint table to alternate space first
    if let ImageColorSpace::Separation {
        alt_space,
        tint_table,
        ..
    } = color_space
    {
        let n_pixels = (width * height) as usize;
        let no = tint_table.num_outputs as usize;
        let mut expanded = vec![0u8; n_pixels * no];
        let mut alt_comps = vec![0.0f32; no];
        for i in 0..n_pixels {
            let tint = image_data.get(i).copied().unwrap_or(0) as f32 / 255.0;
            tint_table.lookup_1d(tint, &mut alt_comps);
            for c in 0..no {
                expanded[i * no + c] = (alt_comps[c].clamp(0.0, 1.0) * 255.0 + 0.5) as u8;
            }
        }
        return merge_rgb_with_smask(&expanded, smask_data, alt_space, width, height, icc);
    }
    if let ImageColorSpace::DeviceN {
        alt_space,
        tint_table,
        ..
    } = color_space
    {
        let ni = tint_table.num_inputs as usize;
        let no = tint_table.num_outputs as usize;
        let n_pixels = (width * height) as usize;
        let mut expanded = vec![0u8; n_pixels * no];
        let mut inputs = vec![0.0f32; ni];
        let mut alt_comps = vec![0.0f32; no];
        for i in 0..n_pixels {
            let si = i * ni;
            for (c, inp) in inputs.iter_mut().enumerate() {
                *inp = image_data.get(si + c).copied().unwrap_or(0) as f32 / 255.0;
            }
            tint_table.lookup_nd(&inputs, &mut alt_comps);
            for c in 0..no {
                expanded[i * no + c] = (alt_comps[c].clamp(0.0, 1.0) * 255.0 + 0.5) as u8;
            }
        }
        return merge_rgb_with_smask(&expanded, smask_data, alt_space, width, height, icc);
    }

    let n_pixels = (width * height) as usize;
    let mut rgba = vec![255u8; n_pixels * 4];
    let n_comps = color_space.num_components();

    // For CMYK data, try ICC bulk conversion first (matches samples_to_rgba quality)
    if n_comps == 4 {
        if let Some(cache) = icc {
            if let Some(cmyk_hash) = cache.default_cmyk_hash() {
                let cmyk_data = if image_data.len() >= n_pixels * 4 {
                    &image_data[..n_pixels * 4]
                } else {
                    image_data
                };
                if let Some(rgb) = cache.convert_image_8bit(cmyk_hash, cmyk_data, n_pixels) {
                    for i in 0..n_pixels {
                        let alpha = smask_data.get(i).copied().unwrap_or(255);
                        let dst = i * 4;
                        let (r, g, b) = (rgb[i * 3], rgb[i * 3 + 1], rgb[i * 3 + 2]);
                        if alpha == 255 {
                            rgba[dst] = r;
                            rgba[dst + 1] = g;
                            rgba[dst + 2] = b;
                            rgba[dst + 3] = 255;
                        } else if alpha == 0 {
                            // rgba already zeroed by default 255, need to zero
                            rgba[dst] = 0;
                            rgba[dst + 1] = 0;
                            rgba[dst + 2] = 0;
                            rgba[dst + 3] = 0;
                        } else {
                            let a = alpha as u16;
                            rgba[dst] = ((r as u16 * a + 127) / 255) as u8;
                            rgba[dst + 1] = ((g as u16 * a + 127) / 255) as u8;
                            rgba[dst + 2] = ((b as u16 * a + 127) / 255) as u8;
                            rgba[dst + 3] = alpha;
                        }
                    }
                    return rgba;
                }
            }
        }
    }

    for i in 0..n_pixels {
        let alpha = smask_data.get(i).copied().unwrap_or(255);
        let dst = i * 4;
        match n_comps {
            3 => {
                // RGB
                let src = i * 3;
                rgba[dst] = image_data.get(src).copied().unwrap_or(0);
                rgba[dst + 1] = image_data.get(src + 1).copied().unwrap_or(0);
                rgba[dst + 2] = image_data.get(src + 2).copied().unwrap_or(0);
            }
            1 => {
                // Gray
                let g = image_data.get(i).copied().unwrap_or(0);
                rgba[dst] = g;
                rgba[dst + 1] = g;
                rgba[dst + 2] = g;
            }
            4 => {
                // CMYK → RGB (PLRM fallback when ICC not available)
                let src = i * 4;
                let c = image_data.get(src).copied().unwrap_or(0) as f64 / 255.0;
                let m = image_data.get(src + 1).copied().unwrap_or(0) as f64 / 255.0;
                let y = image_data.get(src + 2).copied().unwrap_or(0) as f64 / 255.0;
                let k = image_data.get(src + 3).copied().unwrap_or(0) as f64 / 255.0;
                rgba[dst] = ((1.0 - c) * (1.0 - k) * 255.0 + 0.5) as u8;
                rgba[dst + 1] = ((1.0 - m) * (1.0 - k) * 255.0 + 0.5) as u8;
                rgba[dst + 2] = ((1.0 - y) * (1.0 - k) * 255.0 + 0.5) as u8;
            }
            _ => {
                // Unknown — treat as black
            }
        }
        // Premultiply alpha (tiny-skia expects premultiplied RGBA)
        if alpha == 255 {
            rgba[dst + 3] = 255;
        } else if alpha == 0 {
            rgba[dst] = 0;
            rgba[dst + 1] = 0;
            rgba[dst + 2] = 0;
            rgba[dst + 3] = 0;
        } else {
            let a = alpha as u16;
            rgba[dst] = ((rgba[dst] as u16 * a + 127) / 255) as u8;
            rgba[dst + 1] = ((rgba[dst + 1] as u16 * a + 127) / 255) as u8;
            rgba[dst + 2] = ((rgba[dst + 2] as u16 * a + 127) / 255) as u8;
            rgba[dst + 3] = alpha;
        }
    }
    rgba
}

fn expand_bits_to_bytes(
    data: &[u8],
    bpc: u32,
    width: u32,
    height: u32,
    components: u32,
    is_indexed: bool,
) -> Vec<u8> {
    if bpc == 0 || bpc == 8 {
        return data.to_vec();
    }

    let max_val = ((1u32 << bpc) - 1) as f64;
    let samples_per_row = width * components.max(1);
    let mut result = Vec::with_capacity((width * height * components.max(1)) as usize);

    for row in 0..height {
        let row_bit_offset = row as usize * ((samples_per_row * bpc).div_ceil(8) * 8) as usize;
        for col in 0..samples_per_row {
            let bit_offset = row_bit_offset + (col * bpc) as usize;
            let byte_offset = bit_offset / 8;
            let bit_shift = bit_offset % 8;

            if byte_offset >= data.len() {
                result.push(0);
                continue;
            }

            // Extract bpc bits
            let mut val = 0u32;
            let mut bits_remaining = bpc;
            let mut cur_byte = byte_offset;
            let mut cur_bit = bit_shift;

            while bits_remaining > 0 && cur_byte < data.len() {
                let available = 8 - cur_bit as u32;
                let take = bits_remaining.min(available);
                let shift = available - take;
                let mask = ((1u32 << take) - 1) << shift;
                val = (val << take) | ((data[cur_byte] as u32 & mask) >> shift);
                bits_remaining -= take;
                cur_bit = 0;
                cur_byte += 1;
            }

            // For Indexed color spaces, values are palette indices — keep raw.
            // For other color spaces, scale to 0-255.
            if is_indexed {
                result.push(val as u8);
            } else {
                result.push((val as f64 / max_val * 255.0 + 0.5) as u8);
            }
        }
    }

    result
}

/// Convert a PDF blend mode name to a numeric code.
fn blend_mode_from_name(name: &[u8]) -> u8 {
    match name {
        b"Normal" | b"Compatible" => 0,
        b"Multiply" => 1,
        b"Screen" => 2,
        b"Overlay" => 3,
        b"Darken" => 4,
        b"Lighten" => 5,
        b"ColorDodge" => 6,
        b"ColorBurn" => 7,
        b"HardLight" => 8,
        b"SoftLight" => 9,
        b"Difference" => 10,
        b"Exclusion" => 11,
        b"Hue" => 12,
        b"Saturation" => 13,
        b"Color" => 14,
        b"Luminosity" => 15,
        _ => 0,
    }
}

fn is_whitespace_byte(b: u8) -> bool {
    matches!(b, b' ' | b'\t' | b'\r' | b'\n' | 0x0C | 0x00)
}

fn is_delimiter_or_ws(b: u8) -> bool {
    is_whitespace_byte(b)
        || matches!(
            b,
            b'(' | b')' | b'<' | b'>' | b'[' | b']' | b'{' | b'}' | b'/' | b'%'
        )
}

/// Evaluate a PDF function at 256 evenly-spaced points in [0,1] to build a transfer table.
fn sample_transfer_function(func: &crate::resources::function::PdfFunction) -> Vec<f64> {
    (0..256)
        .map(|i| {
            let t = i as f64 / 255.0;
            let result = func.evaluate(&[t]);
            result.first().copied().unwrap_or(t).clamp(0.0, 1.0)
        })
        .collect()
}

/// Apply transfer functions to RGB image pixel data (in-place).
///
/// `data` is interleaved RGB (3 bytes per pixel) or RGBA (4 bytes per pixel).
/// Transfer tables are 256-sample [0,1]→[0,1] lookup tables.
fn apply_transfer_to_image(
    data: &mut [u8],
    transfer: &stet_graphics::device::TransferState,
    components: usize,
) {
    // Build 256-entry u8 lookup tables for each RGB channel
    let (r_table, g_table, b_table) = if let Some(ref color) = transfer.color {
        // Per-component transfer: [R, G, B, Gray]
        let r = build_u8_lut(color[0].as_ref().map(|v| &v[..]));
        let g = build_u8_lut(color[1].as_ref().map(|v| &v[..]));
        let b = build_u8_lut(color[2].as_ref().map(|v| &v[..]));
        (r, g, b)
    } else if let Some(ref gray) = transfer.gray {
        // Single function applied to all channels
        let lut = build_u8_lut(Some(&gray[..]));
        (lut, lut, lut)
    } else {
        return; // Identity — nothing to do
    };

    // Apply LUT per channel
    let stride = components;
    for pixel in data.chunks_exact_mut(stride) {
        if pixel.len() >= 3 {
            pixel[0] = r_table[pixel[0] as usize];
            pixel[1] = g_table[pixel[1] as usize];
            pixel[2] = b_table[pixel[2] as usize];
        }
    }
}

/// Apply transfer functions to a DeviceColor (fill/stroke).
fn apply_transfer_to_color(
    color: &DeviceColor,
    transfer: &stet_graphics::device::TransferState,
) -> DeviceColor {
    if let Some(ref color_tables) = transfer.color {
        // Per-component transfer: [R, G, B, Gray]
        let r = apply_transfer_component(color.r, color_tables[0].as_ref().map(|v| &v[..]));
        let g = apply_transfer_component(color.g, color_tables[1].as_ref().map(|v| &v[..]));
        let b = apply_transfer_component(color.b, color_tables[2].as_ref().map(|v| &v[..]));
        DeviceColor::from_rgb(r, g, b)
    } else if let Some(ref gray) = transfer.gray {
        let r = apply_transfer_component(color.r, Some(&gray[..]));
        let g = apply_transfer_component(color.g, Some(&gray[..]));
        let b = apply_transfer_component(color.b, Some(&gray[..]));
        DeviceColor::from_rgb(r, g, b)
    } else {
        color.clone()
    }
}

/// Look up a single f64 component [0,1] through a transfer table.
fn apply_transfer_component(value: f64, table: Option<&[f64]>) -> f64 {
    match table {
        None => value,
        Some(t) if t.len() != 256 => value,
        Some(t) => {
            let idx = (value * 255.0).clamp(0.0, 255.0);
            let lo = idx.floor() as usize;
            let hi = (lo + 1).min(255);
            let frac = idx - lo as f64;
            let v0 = t[lo];
            let v1 = t[hi];
            (v0 + frac * (v1 - v0)).clamp(0.0, 1.0)
        }
    }
}

/// Build a 256-entry u8 lookup table from a transfer table.
fn build_u8_lut(table: Option<&[f64]>) -> [u8; 256] {
    let mut lut = [0u8; 256];
    match table {
        Some(t) if t.len() == 256 => {
            for (i, v) in lut.iter_mut().enumerate() {
                *v = (t[i].clamp(0.0, 1.0) * 255.0 + 0.5) as u8;
            }
        }
        _ => {
            for (i, v) in lut.iter_mut().enumerate() {
                *v = i as u8;
            }
        }
    }
    lut
}