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Fix Rect::ExpandToMinTransformedSize to return the input rectangle when no expansion is needed, and remove 1-pixel roundrect to rect simplification - #189808
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This pull request updates the rectangle expansion logic in rect.h to return the original rectangle without modification if its current size already meets or exceeds the minimum local size. Additionally, a unit test has been renamed and a new regression test has been added in rect_unittests.cc to verify this behavior with fractional sizes. There are no review comments, and I have no feedback to provide.
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This pull request modifies the rectangle expansion logic in Impeller's geometry library to return the unmodified rectangle when its current dimensions are already greater than or equal to the minimum required size. Additionally, a regression test has been added to verify this behavior with fractional dimensions. There are no review comments, and I have no feedback to provide.
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@flar PTAL. I went with your suggestion in #189807 (comment) and also removed the 1-pixel roundrect to rect simplification. The golden results show a very subtle reduction in opacity of pixels at the end of sub-pixel-width roundrects. That is what we expect from this change: https://flutter-gold.skia.org/search?crs=github&issue=189808&patchsets=2 |
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Rect::ExpandToMinTransformedSize to return the input rectangle when no expansion is neededRect::ExpandToMinTransformedSize to return the input rectangle when no expansion is needed, and remove 1-pixel roundrect to rect simplification
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…rectangle when no expansion is needed, and remove 1-pixel roundrect to rect simplification (#189885) This was a manual cherry pick of #189808. ### Issue Link: What is the link to the issue this cherry-pick is addressing? #189807 ### Impact Description: What is the impact (ex. visual jank on Samsung phones, app crash, cannot ship an iOS app)? Does it impact development (ex. flutter doctor crashes when Android Studio is installed), or the shipping of production apps (the app crashes on launch). This information is for domain experts and release engineers to understand the consequences of saying yes or no to the cherry pick. Rounded rectangles are sometimes incorrectly rendered as non-rounded rectangles. This issue is present when impeller is enabled Impeller with SDF rendering. In the beta channel, Impeller with SDF rendering is the default when building apps for desktop platforms: macOS, Linux, and Windows. ### Changelog Description: Explain this cherry pick: * In one line that is accessible to most Flutter developers. * That describes the state prior to the fix. * That includes which platforms are impacted. See [best practices](https://github.com/flutter/flutter/blob/main/docs/releases/Hotfix-Documentation-Best-Practices.md) for examples. < Replace with changelog description here > [flutter/189807](#189807): Rounded rectangles are sometimes incorrectly rendered as non-rounded rectangles. ### Workaround: Is there a workaround for this issue? Disable Impeller, falling back to Skia rendering. ### Risk: What is the risk level of this cherry-pick? ### Test Coverage: Are you confident that your fix is well-tested by automated tests? ### Validation Steps: What are the steps to validate that this fix works? The demo app at #189807 should render two rounded rectangles, rather than one normal rectangle and one rounded rectangle.
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flutter/flutter@2a2a79d...b65f4d9 2026-07-24 [email protected] Add dart_runtime_service_vm_aot.dart.snapshot to the snapshot list in the macOS code signing configuration (flutter/flutter#189981) 2026-07-24 [email protected] Roll Fuchsia Test Scripts from wLST_A-xfOeGT_5mj... to E8hJ1AfK8CtGtaES0... (flutter/flutter#189956) 2026-07-23 [email protected] Consolidate AndroidArch and DarwinArch into CpuArch (flutter/flutter#189315) 2026-07-23 [email protected] Roll Dart SDK from 9258584f98b8 to e3fc57eae9eb (7 revisions) (flutter/flutter#189949) 2026-07-23 [email protected] [flutter_tools] Do not always wait for the full timeout when running Spotlight to locate Android Studio on macOS (flutter/flutter#189952) 2026-07-23 [email protected] Roll Skia from 1d8bf9270d8c to 6e9c4687c001 (15 revisions) (flutter/flutter#189954) 2026-07-23 [email protected] [flutter_tools] Initialize Cache.flutterRoot at the start of the upgrade_test suite (flutter/flutter#189937) 2026-07-23 [email protected] Parse AndroidX property in gradle.properties (flutter/flutter#188372) 2026-07-23 [email protected] [Impeller]Use the IO context for OpenGL program setup (flutter/flutter#185723) 2026-07-23 [email protected] Allow building projects lacking Runner.xcworkspace (flutter/flutter#186239) 2026-07-23 [email protected] [flutter_tools] Invalidate WebEntrypointTarget when plugin set changes (flutter/flutter#189460) 2026-07-23 [email protected] Bump devtools_shared to 13.1.0 (flutter/flutter#189507) 2026-07-23 [email protected] forceNdkDownload should skip configuring cmake when ndk-build is used (flutter/flutter#187201) 2026-07-23 [email protected] Disable execution order shuffling for the flutter_tools upgrade_test suite (flutter/flutter#189920) 2026-07-23 [email protected] Move WindowManager outside of WidgetsApp (flutter/flutter#188866) 2026-07-23 [email protected] Roll Skia from 3424966b8a2b to 1d8bf9270d8c (3 revisions) (flutter/flutter#189901) 2026-07-23 [email protected] Roll Fuchsia Linux SDK from GswhlPRO-D1qSNclx... to 9org0yL3yZkp80x5S... (flutter/flutter#189898) 2026-07-23 [email protected] Remove outdated logs that were added to track #172636 (flutter/flutter#189282) 2026-07-23 [email protected] Roll Skia from 5e183e5aeac5 to 3424966b8a2b (33 revisions) (flutter/flutter#189890) 2026-07-23 [email protected] [examples] Use super parameters in missed spots (flutter/flutter#186194) 2026-07-23 [email protected] [flutter_tools] Bound Spotlight mdfind execution with timeout on macOS (flutter/flutter#189461) 2026-07-23 [email protected] Fix non primary buttons not being captured on windows (flutter/flutter#188394) 2026-07-22 [email protected] Listen to log reader before VM Service and make delay configurable (flutter/flutter#187202) 2026-07-22 [email protected] Roll Dart SDK from 1e65011ee004 to 9258584f98b8 (7 revisions) (flutter/flutter#189883) 2026-07-22 [email protected] Adds skill for generating engine diffs for new releases. (flutter/flutter#189869) 2026-07-22 [email protected] [ios,macos] Add Swift Sourcekit LSP support (flutter/flutter#189761) 2026-07-22 [email protected] [iOS] Mark DisplayLinkManager.shared and init() @mainactor (flutter/flutter#189815) 2026-07-22 [email protected] Fix `Rect::ExpandToMinTransformedSize` to return the input rectangle when no expansion is needed, and remove 1-pixel roundrect to rect simplification (flutter/flutter#189808) 2026-07-22 [email protected] Skip emulator.getEmulators test (flutter/flutter#189879) 2026-07-22 [email protected] Fix null terminator in input truncates clipboard (flutter/flutter#188652) 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 #189807
See the issue for more context.
Adds a unit test that fails without this change, and passes with this change.
Verified the demo app in the issue renders properly with this change.
From the issue:
Root cause and fix
Rect::ExpandToMinTransformedSize always constructs a new expanded rectangle from the input Rect from its center point and half-extents.
If the input rectangle is already large enough and does not need expansion, this should return an identical rectangle. The returned rectangle is equality-checked against the input in Canvas::DrawRoundRect to determine whether expansion happened. That code assumes that if the output does not equal the input, pixel-expansion happened, which means that the rounded rect had sub-pixel dimensions and can be safely drawn as a non-rounded rectangle.
The issue is that for certain cases, particularly with non-integer sizes, ExpandToMinTransformedSize returns a different rectangle even if no expansion happened. This is due to small floating point imprecisions when constructing the new rectangle using the input rectangle's center and half-extents.
To fix this, ExpandToMinTransformedSize should not construct a new rectangle unless expansion is actually needed.
Removal of 1-pixel roundrect to rect simplification
This PR also removes the 1-pixel roundrect to rect simplification in
Canvas::DrawRoundRect. As described in #189807 (comment), this optimization resulted in slightly different colors at the tips of thin roundrects.Pre-launch Checklist
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