Linux glyph gamma correction#187122
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This pull request introduces gamma/contrast correction for text rendering on Linux platforms within Impeller. It calculates a contrast factor based on the text color's relative luminance in text_contents.cc and applies it in the glyph_atlas.frag shader to adjust glyph coverage. The Mali offline compiler metrics have been updated to reflect the shader changes. Feedback suggests optimizing the shader by removing a redundant clamp call on the coverage value, as it is already guaranteed to be within the [0.0, 1.0] range.
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(b-luk is ooo but I'd like this to be on his radar since he looked into similar issues on macos) |
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flutter/flutter@c8f2f16...e70534d 2026-05-28 [email protected] Linux glyph gamma correction (flutter/flutter#187122) 2026-05-28 [email protected] [iOS] Eliminate strong retain cycle from VSyncClient (flutter/flutter#187164) 2026-05-28 [email protected] Revert "[pubspec] Bump Dart SDK constraint to ^3.13.0 (#186957)" (flutter/flutter#187209) 2026-05-28 [email protected] Roll Skia from f1b8ba877c07 to 32acea791248 (3 revisions) (flutter/flutter#187220) 2026-05-27 [email protected] Roll Fuchsia Linux SDK from k9EizfEGJO4WwQN9-... to SBpmmPxqx3lAvGojE... (flutter/flutter#187211) 2026-05-27 [email protected] [Impeller] Add block-compressed texture format support (BC, ETC2, ASTC) (flutter/flutter#187077) 2026-05-27 [email protected] Disable analyzer (flutter/flutter#187205) 2026-05-27 [email protected] [Flutter GPU] Add explicit draw counts (reland) (flutter/flutter#187192) 2026-05-27 [email protected] [Flutter GPU] Inject per-backend defines into shader bundle compilation (flutter/flutter#187081) 2026-05-27 [email protected] Roll Skia from fa944af10f91 to f1b8ba877c07 (13 revisions) (flutter/flutter#187194) 2026-05-27 [email protected] Fixes bug when changing accessibilityFocusBlockType doesn't update ch… (flutter/flutter#186596) 2026-05-27 [email protected] Roll pub packages (flutter/flutter#187191) 2026-05-27 [email protected] [web, tool] Support recompiling shaders and unify asset processing (2nd try) (flutter/flutter#186902) 2026-05-27 [email protected] Fix crash if FlView is destroyed during a draw. (flutter/flutter#186848) 2026-05-27 [email protected] Roll Packages from fc795e5 to 4b424d7 (4 revisions) (flutter/flutter#187174) 2026-05-27 [email protected] Stop prefetching Swift packages in pub get (flutter/flutter#187113) 2026-05-27 [email protected] Update CI with newer android sdk package (flutter/flutter#187143) 2026-05-27 [email protected] Add a tag to the Linux platform properties in .ci.yaml that specifies x64 CPUs (flutter/flutter#187124) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC [email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
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fixes: #186975
Impeller renders in the linear space, whereas the glyphs coming from freetype are assuming gamma space. This resulted in light text looking washed out but dark text looking fine.
This PR introduces a gamma correction that boost's the gamma of a color based on it's luminance, so black colors look the same, but light colors get boosted to the tune of 2.2, which is the gamma value for sRGB.
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(These are screenshots taking over chrome remote desktop, thus some compression artifacts)
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