SweepGradient angle and TileMode documentation (#172406)
# Improve SweepGradient and TileMode Documentation ## Description This PR enhances the documentation for `SweepGradient` and `TileMode` to provide clearer guidance on how angles are measured and how tile modes affect sweep gradient rendering. ### Changes 1. **SweepGradient Documentation**: - Clarified angle measurement in radians from the positive x-axis - Documented angle normalization behavior for values outside [0, 2π] - Added detailed explanations of how each `TileMode` affects rendering outside the angular sector 2. **Gradient.sweep Constructor**: - Improved parameter documentation - Added a practical example showing how to create a 90-degree sweep gradient - Clarified the relationship between color stops and angles 3. **TileMode Documentation**: - Added sweep gradient-specific behavior to each `TileMode` variant - Clarified how each mode (clamp, repeated, mirror, decal) affects rendering outside the angular sector - Improved overall documentation structure for gradient edge behavior ## Related Issues Fixes #166206 ## Testing - Verified documentation changes by reviewing the generated API docs - Ensured all examples compile and render as expected ## Breaking Changes None - this is purely a documentation improvement. ## Additional Notes The changes make it much clearer how `startAngle` and `endAngle` interact with different `TileMode` values, which was a source of confusion in the original issue. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md --------- Co-authored-by: Victor Sanni <victorsanniay@gmail.com>
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