Fix bug where offscreen layers would erroneously draw black pixels - #55762
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Fix bug where offscreen layers would erroneously draw black pixels#55762Abbondanzo wants to merge 1 commit into
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…55762) Summary: On API <= 28, `clipWithAntiAliasing` uses `saveLayer` for anti-aliased border radius clipping. When a view is partially off-screen, the GPU only renders into the visible portion of the `saveLayer` buffer, leaving off-screen pixels as opaque black. These black pixels survive Porter-Duff compositing and appear as visible artifacts. Adding `canvas.clipRect(0, 0, view.width, view.height)` before `saveLayer` forces HWUI to properly initialize the offscreen buffer relative to the GPU scissor. The clip is in local coordinates, so it stays correct across parent transform animations and scrolling offsets. Changelog: [Internal] Reviewed By: NickGerleman Differential Revision: D94447724
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This pull request was successfully merged by @Abbondanzo in f88946d When will my fix make it into a release? | How to file a pick request? |
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…56336) Summary: Pull Request resolved: #56336 Moves `clipRect` inside the outer `saveLayer` in `clipWithAntiAliasing()` to fix blank rendering on API 24 (Nougat) devices. #55762 added `canvas.withClip()` to fix black pixels on partially off-screen views. However, it wrapped the entire compositing chain in an extra `save()`/`clipRect`/`restore()`, creating a triple-nested save/restore stack (`save` -> `saveLayer` -> `saveLayer(DST_IN)`) that breaks Porter-Duff compositing on API 24's HWUI renderer. Moving `clipRect` inside the `saveLayer` reduces nesting from 3 to 2 levels while preserving the black-pixel mitigation. The `saveLayer` already saves and restores clip state, so a separate `save()`/`restore()` wrapper is unnecessary. Changelog: [Android][Fixed] - Fix image content disappearing on API 24 (Nougat) when antialiased border radius clipping is applied Reviewed By: NickGerleman Differential Revision: D99677658 fbshipit-source-id: 55a9c84655cc08b05b95c29725492b9b8f759331
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Summary:
On API <= 28,
clipWithAntiAliasingusessaveLayerfor anti-aliased border radius clipping. When a view is partially off-screen, the GPU only renders into the visible portion of thesaveLayerbuffer, leaving off-screen pixels as opaque black. These black pixels survive Porter-Duff compositing and appear as visible artifacts.Adding
canvas.clipRect(0, 0, view.width, view.height)beforesaveLayerforces HWUI to properly initialize the offscreen buffer relative to the GPU scissor. The clip is in local coordinates, so it stays correct across parent transform animations and scrolling offsets.Changelog: [Internal]
Differential Revision: D94447724