…43288)

Manual roll requested by [email protected]

https://dart.googlesource.com/sdk.git/+log/81cdbe69a16b..7a233f843402

2023-06-27 [email protected] Version 3.1.0-250.0.dev
2023-06-26 [email protected] Version 3.1.0-249.0.dev
2023-06-26 [email protected] Version 3.1.0-248.0.dev
2023-06-26 [email protected] Version 3.1.0-247.0.dev

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC [email protected],[email protected],[email protected] on the revert to ensure that a human
is aware of the problem.

To file a bug in Flutter Engine: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Investigated as part of
flutter/flutter#127232.

This took some time to work out, but:
* The amount of blending applied to the source color needs to be
weighted by the destination alpha, which is pretty sensible behavior.
This is in addition to applying source-over behavior with the resulting
blended color.
* All of the blend functions assume that the color is already
premultiplied, so remove the unpremultiply/premultiply surrounding the
blend call.

All of the blend modes now visually match up with the [Flutter
docs](https://api.flutter.dev/flutter/dart-ui/BlendMode.html), except
for ColorBurn and Saturation, which appear to have a slight
miscalculation going on with the red channel.

https://dart.googlesource.com/sdk.git/+log/7a233f843402..abfa59f66c42

2023-06-27 [email protected] Version 3.1.0-253.0.dev
2023-06-27 [email protected] Version 3.1.0-252.0.dev
2023-06-27 [email protected] Version 3.1.0-251.0.dev

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC [email protected],[email protected] on the revert to ensure that a human
is aware of the problem.

To file a bug in Flutter Engine: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

…3292)