Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 35a0ba08385cfdc1e374a1622a229ccbe618f0ed
https://github.com/WebKit/WebKit/commit/35a0ba08385cfdc1e374a1622a229ccbe618f0ed
Author: Sam Weinig <[email protected]>
Date: 2022-09-26 (Mon, 26 Sep 2022)
Changed paths:
M
LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/animation-types/accumulation-per-property-001-expected.txt
M
LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/animation-types/accumulation-per-property-002-expected.txt
M
LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/animation-types/addition-per-property-001-expected.txt
M
LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/animation-types/addition-per-property-002-expected.txt
M Source/WebCore/platform/graphics/ColorBlending.cpp
M Source/WebCore/platform/graphics/ColorInterpolation.h
Log Message:
-----------
[web-animations] additive/accumulative color blending fails to yield
intermediary out-of-bounds values
https://bugs.webkit.org/show_bug.cgi?id=242185
<rdar://96593559>
Reviewed by Antoine Quint.
Additive (and Accumulative, which is identical for colors) blending in web
animations is
implemented by calling the blend function two extra times:
1. First to add the 'base' color to the 'from' color, giving us 'additive-from'.
e.g. blend(base, from, add-operation)
2. Second to add the 'base' color to the 'to' color, giving us the
'additive-to'.
e.g. blend(base, to, add-operation)
It then interpolates 'additive-from' to 'additive-to', using the normal,
'replace', blend
path. Further, it expects 'additive-from' and 'additive-to' to be unclamped
color values.
To support this scheme, the blend function for Color was updated to implement
support for
the add operation, using a new addColorComponents helper (which is just a
wrapper around
interpolatColorComponents that specifies 100% of each color) which uses
ExtendedSRGBA to
avoid clamping. The normal, replace, blend path was changed to use the now
standard color
interpolation function, interpolateColorComponents, which supports all
interpolation methods
not just SRGB, to make it match convention. To maintain compatability with
existing animmation
interpolation, the result of the replace blend is clipped to the sRGB gamut.
This clipping
is suspect, but the tests currently require this. Additional discussion with
the WG is
needed to deterimine the best path forward.
*
LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/animation-types/accumulation-per-property-001-expected.txt:
*
LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/animation-types/accumulation-per-property-002-expected.txt:
*
LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/animation-types/addition-per-property-001-expected.txt:
*
LayoutTests/imported/w3c/web-platform-tests/web-animations/animation-model/animation-types/addition-per-property-002-expected.txt:
* Source/WebCore/platform/graphics/ColorBlending.cpp:
(WebCore::blend):
* Source/WebCore/platform/graphics/ColorInterpolation.h:
(WebCore::interpolateAlphaPremulitplied): Add a clamp, needed for the additive
blend, as alpha > 1 doesn't really make sense.
(WebCore::addColorComponents):
Canonical link: https://commits.webkit.org/254850@main
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