vello_cpu keeps every path's coverage (alpha) values in one buffer until
the scene is rasterized, and a strip packs its index into that buffer in
31 bits; Strip::new asserts it fits. A page that painted one form 2^22
times over (22 nested forms, each drawing the next twice) grew the
buffer past 2^31 values at about 7 GB and panicked, and the page failed.
- vello_common (2): StripStorage::room_for_path{,_within} says whether
one more path's coverage, at most the whole surface counted twice,
still fits below that limit or a smaller one.
- vello_cpu (1): the single-threaded dispatcher leaves out fills,
strokes, fast rectangles and layer clips once there is no room,
records it (RenderContext::coverage_full) and can be kept to fewer
values (set_max_coverage).
- hayro (31): RenderSettings::max_coverage passes that limit down, and
a page whose paths were left out reports
InterpreterWarning::ContentTruncated, which PdfCraft already shows as
content skipped past the page's safety budget.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
vello_cpu 0.0.8's clip_color, shared by the nonseparable blend modes,
divided 0 by 0 when a gray's equal components were rounded just below 0
or above 1 after set_lum. The NaN drew the pixel black at the source's
alpha whatever the backdrop: nine gray levels under /BM /Color in an
empty isolated group (0.96 g among them) rendered (0, 0, 0), and two
more at half opacity came out wrong.
Vendor vello_cpu 0.0.8 (Apache-2.0 OR MIT) with a backport of
linebender/vello#2000, which clips only when the denominator is
positive. No vello_cpu release carries the fix yet; drop the copy when
one does.
Tests in it::nonseparable_gray run every gray level. The two Color
ramps fail with the unpatched blend.rs. The Luminosity ramp (black over
each opaque gray, upstream's other case) passes either way here: pages
use the u8 pipeline, and that case only failed in the f32 one; it stays
as a guard.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SqmHYx8FiWM5PcsoiErgp9
mtlcl410andClaude Opus 5.5
KenM76andClaude Opus 5.5