[web] Fix canvas z-index leaking across repaints when element is reused. #17378
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yjbanov
approved these changes
Mar 27, 2020
| canvas.id = kTestId; | ||
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| sceneElement.remove(); | ||
| // Clear so resources are marked for reuse. |
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nit: move the comment one line down
| // If a canvas is the first element we set z-index = -1 to workaround | ||
| // blink compositing bug. To make sure this does not leak when reused | ||
| // reset z-index. | ||
| _canvas.style.removeProperty('z-index'); |
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Wouldn't the effect be the same if you put this into an else branch of the if (isFirstChildElement) check below? Just so we have all the z-index related code together in one spot.
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No since it never reaches that code when you reuse from reuse_pool
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I'm referring to line 127. It does reach it. I don't see any early return statement. Am I missing something?
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Ah got it. So yes thats a good option as well. But this way we are executing the removeProperty call only if we reuse instead of doing it at startup as well.
engine-flutter-autoroll
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goderbauer
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Apr 16, 2020
…ed. (flutter#17378) * Fix z-index leak. Add test for canvas reuse * add regression test * update golden locks * fix analysis errors
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Related bug: flutter/flutter#51514
Added test that verifies canvas is reused and zindex is reset when paint order changes (similar to hover/repaint reproduced in related issue).