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Extended colors should be clamped so they look the same in SDR and HDR layers. #47418

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Extended colors should be clamped so they look the same in SDR and HDR layers. #47418

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@mattwoodrow mattwoodrow commented Jul 1, 2025 •
edited by webkit-early-warning-system
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d0099fa

Extended colors should be clamped so they look the same in SDR and HDR layers.
https://bugs.webkit.org/show_bug.cgi?id=292226
<rdar://150231788>

Reviewed by NOBODY (OOPS!).

Compute the headroom for extended colors, and tonemap them back into the SDR
range during WebCore::Color->CGColor conversion so that they appear identical
regardless of layer backing store contents format.

* Source/WebCore/platform/graphics/cg/ColorCG.cpp:
(WebCore::headroomForColor):
(WebCore::createCGColor):

d0099fa

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@mattwoodrow
Extended colors should be clamped so they look the same in SDR and HD…
d0099fa 
…R layers.

https://bugs.webkit.org/show_bug.cgi?id=292226
<rdar://150231788>

Reviewed by NOBODY (OOPS!).

Compute the headroom for extended colors, and tonemap them back into the SDR
range during WebCore::Color->CGColor conversion so that they appear identical
regardless of layer backing store contents format.

* Source/WebCore/platform/graphics/cg/ColorCG.cpp:
(WebCore::headroomForColor):
(WebCore::createCGColor):
@mattwoodrow mattwoodrow self-assigned this Jul 1, 2025
@mattwoodrow mattwoodrow added the Images For bugs in image handling. label Jul 1, 2025
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webkit-early-warning-system commented Jul 1, 2025 •
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EWS run on current version of this PR (hash d0099fa)

Misc iOS, visionOS, tvOS & watchOS macOS Linux Windows
✅ 🧪 style ❌ 🛠 ios ❌ 🛠 mac ✅ 🛠 wpe ✅ 🛠 win
✅ 🧪 bindings ❌ 🛠 ios-sim ❌ 🛠 mac-AS-debug ✅ 🧪 wpe-wk2 ⏳ 🧪 win-tests
✅ 🧪 webkitperl ❌ 🧪 ios-wk2 ❌ 🧪 api-mac ✅ 🧪 api-wpe
❌ 🧪 ios-wk2-wpt ❌ 🧪 mac-wk1 ✅ 🛠 wpe-cairo
❌ 🧪 api-ios ❌ 🧪 mac-wk2 ✅ 🛠 gtk
❌ 🛠 vision ❌ 🧪 mac-AS-debug-wk2 ✅ 🧪 gtk-wk2
❌ 🛠 vision-sim ❌ 🧪 mac-wk2-stress ❌ 🧪 api-gtk
⏳ 🧪 vision-wk2 ❌ 🧪 mac-intel-wk2 ✅ 🛠 playstation
❌ 🛠 tv ❌ 🛠 mac-safer-cpp
❌ 🛠 tv-sim
❌ 🛠 watch
❌ 🛠 watch-sim

@mattwoodrow mattwoodrow requested a review from weinig July 1, 2025 02:49
@webkit-ews-buildbot webkit-ews-buildbot added the merging-blocked Applied to prevent a change from being merged label Jul 1, 2025
lilyspiniolas
lilyspiniolas reviewed Jul 1, 2025
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Source/WebCore/platform/graphics/cg/ColorCG.cpp
auto [c1, c2, c3, c4] = cgCompatibleComponents;
std::array<CGFloat, 4> cgFloatComponents { c1, c2, c3, c4 };

return adoptCF(CGColorCreate(cgColorSpace, cgFloatComponents.data()));
auto result = adoptCF(CGColorCreate(cgColorSpace, cgFloatComponents.data()));
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@lilyspiniolas lilyspiniolas Jul 1, 2025 •
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Suggested change
auto result = adoptCF(CGColorCreate(cgColorSpace, cgFloatComponents.data()));
RetainPtr result = adoptCF(CGColorCreate(cgColorSpace, cgFloatComponents.data()));

lilyspiniolas
lilyspiniolas reviewed Jul 1, 2025
View reviewed changes
Source/WebCore/platform/graphics/cg/ColorCG.cpp
auto result = adoptCF(CGColorCreate(cgColorSpace, cgFloatComponents.data()));

if (auto headroom = headroomForColor(color, cgColorSpace); headroom > 1) {
auto info = adoptCF(CGColorConversionInfoCreateForToneMapping(cgColorSpace, headroom, cgColorSpace, 1.0f, kCGToneMappingDefault, nullptr, nullptr));
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@lilyspiniolas lilyspiniolas Jul 1, 2025 •
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Suggested change
auto info = adoptCF(CGColorConversionInfoCreateForToneMapping(cgColorSpace, headroom, cgColorSpace, 1.0f, kCGToneMappingDefault, nullptr, nullptr));
RetainPtr info = adoptCF(CGColorConversionInfoCreateForToneMapping(cgColorSpace, headroom, cgColorSpace, 1.0f, kCGToneMappingDefault, nullptr, nullptr));

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