KenM76andClaude Opus 5.5 05630b5f15 fix(render): a gray drawn with the Color blend mode is no longer drawn black ...

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

2026-10-28 14:45:32 -04:00

..

it

fix(render): a gray drawn with the Color blend mode is no longer drawn black

2026-10-28 14:45:32 -04:00