oxideav-pdf 0.0.2

//! Pure-Rust PDF writer for the oxideav framework — round 1.
//!
//! Round 1 supports a single-page PDF 1.4 document built from one
//! [`oxideav_core::vector::VectorFrame`]. The imaging-model surface
//! emitted is the SVG / PDF intersection that `oxideav-core` already
//! models:
//!
//! * **Paths** — move / line / cubic / quadratic (lifted to cubic) /
//!   elliptic-arc (flattened to cubic) / close.
//! * **Solid + linear/radial gradient fills** (Pattern Type 2 +
//!   Function Type 2 / Type 3 stitching).
//! * **Strokes** — width, cap, join, miter limit, dash array+offset.
//! * **2D affine transforms** (`cm`).
//! * **Groups** with optional opacity (ExtGState `/ca` + `/CA`) and
//!   clip path (`W n`).
//! * **Embedded raster images** as FlateDecode `Image` XObjects with
//!   per-pixel alpha via `SMask`. RGBA8 only — JPEG passthrough,
//!   palette images, and 16-bit depth are round 2.
//!
//! Text rendering, multi-page output, transparency groups beyond a
//! per-`Group` `/ca`+`/CA` opacity, and PDF *reading* are all out of
//! scope for round 1 — see `README.md` for the full deferred list.
//!
//! # Public surface
//!
//! ```rust
//! use oxideav_core::{Group, VectorFrame, time::TimeBase};
//!
//! let frame = VectorFrame {
//!     width: 100.0,
//!     height: 100.0,
//!     view_box: None,
//!     root: Group::default(),
//!     pts: None,
//!     time_base: TimeBase::new(1, 1),
//! };
//! let bytes = oxideav_pdf::write_pdf(&frame).unwrap();
//! assert!(bytes.starts_with(b"%PDF-1.4"));
//! ```
//!
//! The crate also registers itself with [`oxideav_core::CodecRegistry`]
//! so it can be selected via the standard codec-id lookup
//! (`"pdf"`).

pub mod arc;
pub mod error;
pub mod objects;
pub mod operators;
pub mod page;
pub mod resources;
pub mod writer;

pub use error::PdfError;
pub use writer::write_pdf;

use oxideav_core::{
    CodecCapabilities, CodecId, CodecInfo, CodecParameters, CodecRegistry, ContainerRegistry,
    Encoder, Error, Frame, MediaType, Muxer, Packet, Result, StreamInfo, TimeBase, WriteSeek,
};

/// String form of the [`oxideav_core::CodecId`] this crate registers
/// under. Use it from container code that wants to claim PDF as an
/// output target.
pub const CODEC_ID_STR: &str = "pdf";

// ───────────────────────── Encoder ─────────────────────────

struct PdfEncoder {
    output_params: CodecParameters,
    pending: Option<Vec<u8>>,
    eof: bool,
}

fn make_encoder(params: &CodecParameters) -> Result<Box<dyn Encoder>> {
    let mut output_params = params.clone();
    output_params.media_type = MediaType::Video;
    output_params.codec_id = CodecId::new(CODEC_ID_STR);
    Ok(Box::new(PdfEncoder {
        output_params,
        pending: None,
        eof: false,
    }))
}

impl Encoder for PdfEncoder {
    fn codec_id(&self) -> &CodecId {
        &self.output_params.codec_id
    }

    fn output_params(&self) -> &CodecParameters {
        &self.output_params
    }

    fn send_frame(&mut self, frame: &Frame) -> Result<()> {
        match frame {
            Frame::Vector(v) => {
                let bytes = write_pdf(v).map_err(Error::from)?;
                self.pending = Some(bytes);
                Ok(())
            }
            _ => Err(Error::invalid(
                "PDF encoder: only vector frames are accepted (Frame::Vector)",
            )),
        }
    }

    fn receive_packet(&mut self) -> Result<Packet> {
        if let Some(bytes) = self.pending.take() {
            let mut pkt = Packet::new(0, TimeBase::new(1, 1), bytes);
            pkt.flags.keyframe = true;
            return Ok(pkt);
        }
        if self.eof {
            return Err(Error::Eof);
        }
        Err(Error::NeedMore)
    }

    fn flush(&mut self) -> Result<()> {
        self.eof = true;
        Ok(())
    }
}

// ───────────────────────── Muxer ─────────────────────────

struct PdfMuxer {
    output: Box<dyn WriteSeek>,
    written_packet: bool,
}

fn open_muxer(output: Box<dyn WriteSeek>, _streams: &[StreamInfo]) -> Result<Box<dyn Muxer>> {
    Ok(Box::new(PdfMuxer {
        output,
        written_packet: false,
    }))
}

impl Muxer for PdfMuxer {
    fn format_name(&self) -> &str {
        "pdf"
    }

    fn write_header(&mut self) -> Result<()> {
        // The PDF encoder writes a complete file in one packet, so the
        // muxer header is a no-op — the entire byte sequence (header,
        // body, xref, trailer) lands in `write_packet`.
        Ok(())
    }

    fn write_packet(&mut self, packet: &Packet) -> Result<()> {
        if self.written_packet {
            return Err(Error::invalid(
                "PDF muxer: round-1 supports a single page; got more than one packet",
            ));
        }
        use std::io::Write;
        self.output.write_all(&packet.data)?;
        self.written_packet = true;
        Ok(())
    }

    fn write_trailer(&mut self) -> Result<()> {
        // Already self-contained — nothing more to flush.
        Ok(())
    }
}

// ───────────────────────── Registration ─────────────────────────

/// Register the PDF encoder with `codecs`.
pub fn register_codecs(reg: &mut CodecRegistry) {
    let caps = CodecCapabilities::video("pdf_sw")
        .with_intra_only(true)
        .with_lossless(true);
    reg.register(
        CodecInfo::new(CodecId::new(CODEC_ID_STR))
            .capabilities(caps)
            .encoder(make_encoder),
    );
}

/// Register the PDF muxer with `containers`.
pub fn register_containers(reg: &mut ContainerRegistry) {
    reg.register_muxer("pdf", open_muxer);
    reg.register_extension("pdf", "pdf");
}

/// Combined registration — convenience wrapper that calls
/// [`register_codecs`] and [`register_containers`].
pub fn register(codecs: &mut CodecRegistry, containers: &mut ContainerRegistry) {
    register_codecs(codecs);
    register_containers(containers);
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn registration_adds_encoder_and_muxer() {
        let mut codecs = CodecRegistry::new();
        let mut containers = ContainerRegistry::new();
        register(&mut codecs, &mut containers);
        assert!(codecs.has_encoder(&CodecId::new(CODEC_ID_STR)));
        assert!(containers.muxer_names().any(|n| n == "pdf"));
    }
}