Module render 

The pure-Rust page renderer — phase 3 of retiring pdfium (docs/PDF_CONFORMANCE.md, “Retiring pdfium”): the raster of a page’s vector content, text and images that the layout / TableFormer / OCR stages consume — the default renderer since phase 5 (docling-parse’s renderer plugin draws them only under DOCLING_RS_RENDERER=docling-parse).

It draws what docling-parse’s renderer<BLEND2D> draws, in its frame: the page’s crop box on a ceil(width · scale) × ceil(height · scale) white canvas (resolve_canvas_size), y down, the box mapped onto the whole canvas, /Rotate applied to the finished pixels; content-stream semantics as in content; fonts as in font; the anti-aliased rasterizer, strokes, masks, gradients and image blits are tiny-skia’s. It is not byte-identical to that renderer — Blend2D’s font engine, rasterizer and JIT compositor round differently — and the docling-parse shim stays the reference the PDF baselines are pinned to; this renderer is measured against it (tests::against_the_docling_parse_shim).

Modules

color

Colour spaces (ISO 32000-1, 8.6) → device RGB in [0, 1].

content

The content-stream interpreter (ISO 32000-1, 8–9): graphics state, path construction and painting, clipping, text, XObjects, inline images, shadings and patterns, ExtGState, and the widget annotations’ appearance streams — drawn onto a tiny-skia canvas in device space.

font

PDF fonts for the renderer: a font dictionary becomes a LoadedFont that splits strings into codes, gives each code its advance and its glyph outline in text space, or — for Type 3 — its glyph procedure.

function

PDF functions (ISO 32000-1, 7.10): sampled (type 0), exponential (2), stitching (3) and PostScript calculator (4) — what shadings, Separation / DeviceN tint transforms and /Decode-less colour ramps evaluate.

geom

Affine geometry for the renderer: PDF’s [a b c d e f] matrices in f64, applied as x' = a·x + c·y + e, y' = b·x + d·y + f (ISO 32000-1, 8.3.4).

image

Image XObjects and inline images → premultiplied RGBA pixmaps (ISO 32000-1, 8.9): every bit depth, the colour spaces of super::color, /Decode ranges, stencil masks painted in the fill colour, /SMask soft masks, stencil and colour-key /Masks. The sample data comes through the raster’s filter chain, its libjpeg-exact JPEG decoder and its CCITT decoder; JPX and JBIG2 have no decoder here and come out as a mid-gray block (the picture the layout model should see is “a picture”).

objects

Small lopdf helpers shared by the renderer’s modules.

prepass

A pre-pass over a content stream for the two constructs lopdf’s content lexer (0.44) does not hand over intact:

Structs

Renderer

A document’s renderer: the per-document caches (fonts, CMYK table, decoded image samples) that its page renders share. The pipeline renders every page at two scales; hold one Renderer per document across both.

Functions

pixels_for_extent

docling-parse’s pixels_for_extent: ceil(extent − 1e-6).

render_page

One-off Renderer::render_scaled (no cache carried across pages).

render_page_sized

One-off Renderer::render.