Perf test for color filter with saveLayer

[liyuqian]

This should reveal the problem in:
#51975

Fixing that issue should significantly lower the frame rasterization
time.

[liyuqian]

@karhu: I've simplified your reproduction app, and put it inside Flutter's devicelab perf test suite. Do you think that you can directly create a PR like this next time?

As for the two problem you mentioned,

1. "saveLayer with ColorFilter disables the raster cache" will be tracked in saveLayer with ColorFilter/ImageFilter disables raster cache  #51975 and a fix would show a significant improvement in this test.
2. "picture is always recreated under fade transition" is actually something that you can fix in your code. You simply need to add a RepaintBoundary here to not let the fade animation rebuild everything below.

[karhu]

@liyuqian Thanks a lot for your work on this! I went over your changes and it is indeed a great reference for future repro apps. Will definitely give it a try next time 👍

[flar]

The use of the color param as a flag to trigger the use of shadow.color looks a little wonky, but that's not a blocking concern.

LGTM.

[liyuqian]

Oh, I see it. Now I've removed color and changed everything to useColorFilter now. Thanks for the suggestion!

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.