feat(pixel): alpha-blend semi-transparent colours in PutPixel - #1
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PutPixel overwrote the destination verbatim, so a theme colour with a non-opaque alpha -- e.g. WhiteSur's borders rgba(0,0,0,0.12) -- painted as a harsh opaque line instead of a subtle hairline. Composite such colours src-over onto the existing pixel instead. Backward-compatible by construction: A==0xFF (the vast majority of widget paint) still overwrites verbatim, so opaque rendering is byte-identical; A==0 is a no-op. Blending over an opaque destination yields an opaque result, so a surface stays fully opaque for the host compositor. 100% coverage (blend-over-opaque, A==0 no-op, blend-over-empty alpha). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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PutPixeloverwrote the destination verbatim, so a theme colour with a non-opaque alpha — e.g. WhiteSur'sborders rgba(0,0,0,0.12)— painted as a harsh opaque line instead of a subtle hairline. Now such colours are composited src-over onto the existing pixel.Backward-compatible by construction:
A == 0xFF(the vast majority of widget paint) overwrites verbatim → opaque rendering is byte-identical.A == 0is a no-op.100% coverage (blend-over-opaque,
A==0no-op, blend-over-empty alpha).🤖 Generated with Claude Code