NetterSilverandClaude Opus 5.5 37bf4ee986 perf(engine): export page images on worker threads ...

Export > Image spent its time in the PNG, JPEG and TIFF encoders, one
page after another: on a 55-page manual at 150 dpi, drawing every page
took about 0.34 s and encoding it 1.1 s (PNG) to 2.0 s (JPEG).

Exporter::images exports a list of pages, drawing and encoding several
at once on worker threads, each with its own PageRenderer (as
automation's extract_parallel does), and hands the files to a sink in
page order on the calling thread. Workers draw at most one page ahead
of the sink and fewer run when 1 GiB can't hold that many of the
largest page. The first page or sink error stops the export with every
earlier page handed over, as before. A page panic becomes that page's
error, and a panicking sink stops the workers. One page, one core or
wasm keeps the per-page loop. Export > Image and the doc_export_images
tool use it.

Files are byte-identical. One core is left for the interface (at most
8 workers). With examples/export_bench, on a Ryzen with 16 threads
(shared), mean of two medians of 21 runs:
  PNG 150 dpi   1874 -> 340 ms  (-82%)
  JPEG 150 dpi  2106 -> 340 ms  (-84%)
  TIFF 150 dpi  2032 -> 375 ms  (-82%)
  PNG 300 dpi   3804 -> 590 ms  (-84%)

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

2026-10-27 17:41:38 +01:00

..

export_bench.rs

perf(engine): export page images on worker threads

2026-10-27 17:41:38 +01:00