[web] Workaround for compositing bug in chrome/webkit #18128
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| final int poolLength = _pool.length; | ||
| canvasCount += poolLength; | ||
| for (int i = 0; i < poolLength; i++) { | ||
| _pool[i].style.zIndex = (-canvasCount + i).toString(); |
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Unrelated to this change, but the fact that I can never remember what _pool and _reusabltPool contains probably means we could use better names for these variables 😃
| // Possible Blink bugs that are causing this: | ||
| // * https://bugs.chromium.org/p/chromium/issues/detail?id=370604 | ||
| // * https://bugs.chromium.org/p/chromium/issues/detail?id=586601 | ||
| int canvasCount = _canvas == null ? 0 : 1; |
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Why is canvasCount not straight _pool.length?
| element.style.overflow = 'hidden'; | ||
| element.style | ||
| ..overflow = 'hidden' | ||
| ..zIndex = '0'; |
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Don't know if it matters, but z-index: 0 is not the same as default z-index: https://www.w3.org/TR/CSS21/zindex.html
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Yes, spec says it will be treated atomically which seems to help with failure rather than tree order. Since it has single child should not matter.
| List<html.CanvasElement> list = | ||
| contentAfterReuse.querySelectorAll('canvas'); | ||
| expect(list[0].style.zIndex, '-2'); | ||
| expect(list[1].style.zIndex, '-1'); |
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If you have two canvases, with z-index -2 and -1, that means that there's an image or text that's between them. Shouldn't the image/text have a z-index that's between the two canvas' z-indexes? The other issue is that if both a canvas and text have negative z-index, then the canvas will appear on top of text due to the Chrome/Safari bug.
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reverted per offline discussion.
| int _saveContextCount = 0; | ||
| int _activeCanvasCount = 0; | ||
| // Number of elements that have been added to flt-canvas. | ||
| int _activeElementCount = 0; |
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Why not always have a non-null non-empty _pool? Then _canvas becomes _pool.last, and _activeElementCount becomes _pool.length, and we can remove all the null checks.
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pool only tracks canvas(s) if you have more than 1 canvas. activeElementCount tracks both canvas, p and img tags. So if you draw image and then canvas, activeElementCount is 2 at the end.
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Mac Web Engine retry passed in https://ci.chromium.org/p/flutter/builders/try/Mac%20Web%20Engine/3028 |
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Related issues: flutter/gallery#143