pdfcraft/crates/render
cyfung1031 63363ec438
M3: rasters reach egui without a copy on the UI thread (#555)
* M3: rasters reach egui without a copy on the UI thread

Every page, tile and thumbnail raster was copied pixel by pixel on the UI
thread (`ColorImage::from_rgba_premultiplied`), because egui's `Color32` is
4-byte aligned and a `Vec<u8>` isn't. That is 0.5 ms per 1024² tile, 5.4 ms
for a 33 MB page and 36 ms for a 197 MB page, against a 16.7 ms frame.

hayro, vendored patch 7: `render_size` and `render_into` render into a buffer
the caller allocates. `render` is `render_into` on a new pixmap, so its output
is unchanged. pdfcraft-render renders straight into `Pixels`, the same
premultiplied RGBA bytes kept in one 4-byte word per pixel. `Pixels`
dereferences to `[u8]`, so every reader of `RenderedPage::rgba` compiles
unchanged. The canvas reinterprets the words as `Color32`s and hands them to
egui as they are.

Pixels are identical: all 33 renders of #260's test file hash the same. The
UI-thread copy is gone, and rendering a 6182×8000 page takes 67 ms instead of
71–76 ms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* M3: render_into leaves a buffer of the wrong length untouched instead of reaching vello's assert

* M3: regression test for render_into with a wrong-length buffer

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>
2026-10-09 12:28:46 -04:00
..
src M3: rasters reach egui without a copy on the UI thread (#555) 2026-10-09 12:28:46 -04:00
Cargo.toml M3: rasters reach egui without a copy on the UI thread (#555) 2026-10-09 12:28:46 -04:00