ironpress 1.4.3

Pure Rust HTML/CSS/Markdown to PDF converter with layout engine, LaTeX math, tables, images, custom fonts, and streaming output. No browser, no system dependencies.
Documentation 
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use crate::parser::css::CssRule;
use crate::parser::ttf::TtfFont;
use std::collections::HashMap;

use super::engine::CounterState;

/// Shared mutable environment for the layout traversal.
///
/// Bundles the CSS rules, font map, and counter state that flow through
/// every layout function unchanged in shape.
pub(crate) struct LayoutEnv<'a> {
    pub rules: &'a [CssRule],
    pub fonts: &'a HashMap<String, TtfFont>,
    pub counter_state: &'a mut CounterState,
}

/// Containing block information for `position: absolute` elements.
/// Stores the containing block's position and dimensions so the renderer
/// can resolve offsets relative to the nearest positioned ancestor.
#[derive(Debug, Clone, Copy)]
pub struct ContainingBlock {
    /// X-offset of the containing block's left edge from the page left margin.
    pub x: f32,
    /// Width of the containing block.
    pub width: f32,
    /// Height of the containing block.
    pub height: f32,
    /// Depth of the positioned ancestor in the layout stack.
    pub depth: usize,
}

/// Page content-area dimensions (after margins).
#[derive(Debug, Clone, Copy)]
#[allow(dead_code)]
pub struct Viewport {
    pub width: f32,
    pub height: f32,
}

/// Width, height, and font-size inherited from the parent box.
#[derive(Debug, Clone, Copy)]
#[allow(dead_code)]
pub struct ParentBox {
    pub content_width: f32,
    pub content_height: Option<f32>,
    pub font_size: f32,
}

/// Contextual information that flows through the layout tree.
///
/// Replaces scattered `available_width` / `available_height` /
/// `abs_containing_block` parameters with a single struct.
#[derive(Debug, Clone, Copy)]
#[allow(dead_code)]
pub struct LayoutContext {
    pub viewport: Viewport,
    pub parent: ParentBox,
    pub containing_block: Option<ContainingBlock>,
    pub root_font_size: f32,
}

#[allow(dead_code)]
impl LayoutContext {
    /// Width available for the current element (parent content width).
    pub fn available_width(&self) -> f32 {
        self.parent.content_width
    }

    /// Height available for the current element, falling back to viewport.
    pub fn available_height(&self) -> f32 {
        self.parent.content_height.unwrap_or(self.viewport.height)
    }

    /// Return a child context with updated parent dimensions.
    pub fn with_parent(
        &self,
        content_width: f32,
        content_height: Option<f32>,
        font_size: f32,
    ) -> Self {
        LayoutContext {
            parent: ParentBox {
                content_width,
                content_height,
                font_size,
            },
            ..*self
        }
    }

    /// Return a child context with an updated containing block.
    pub fn with_containing_block(&self, cb: Option<ContainingBlock>) -> Self {
        LayoutContext {
            containing_block: cb,
            ..*self
        }
    }
}