Lazily layout content that is hidden via `content-visibility: hidden`
Categories
(Core :: Layout, enhancement)
Tracking
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| Tracking | Status | |
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| firefox106 | --- | fixed |
People
(Reporter: mrobinson, Assigned: mrobinson)
References
Details
Attachments
(1 file)
The containment specification [1] says:
When an element skips its contents, the user agent must change the used value of the contain property so as to turn on layout containment, style containment, paint containment, and size containment. Further, its contents (the flat tree descendants of the element, including both text and elements, or the replaced content of a replaced element) are not painted (as if they had visibility: hidden) and do not respond to hit-testing (as if they had pointer-events: none), and to a large extent do not update their styles at all unless explicitly requested by script (see § 4.3 Restrictions and Clarifications for details).
The user agent should additionally avoid as much layout/rendering work as possible for skipped contents; the combination of heavy containment and making the contents invisible and untouchable enables heavy optimizations. If rendering work is done at some point, the user-agent should retain the previously computed layout state if possible, to allow the skipped contents to be displayed quickly at a later moment.
The idea of this bug is that unless script specifically asks for the size of content that is hidden, we can avoid laying out that content.
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Comment 1•3 years ago
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Updated•3 years ago
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Comment 3•2 years ago
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Sorry, there was a problem with the detection of inactive users. I'm reverting the change.
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Comment 6•2 years ago
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Backed out for causing failures at content-visibility-081.html.
Backout link: https://hg.mozilla.org/integration/autoland/rev/833f27f4d33b62fe14848a1651c2b5e766bcf2e5
Failure log: https://treeherder.mozilla.org/logviewer?job_id=387372098&repo=autoland&lineNumber=1884
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Comment 8•2 years ago
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Backout has been merged to central: https://hg.mozilla.org/mozilla-central/rev/833f27f4d33b
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Comment 10•2 years ago
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Backed out for causing wpt failures.
Backout link: https://hg.mozilla.org/integration/autoland/rev/2f6dd68ad96a2e98d47a25b2f7503bfc1d2949c2
Failure log: https://treeherder.mozilla.org/logviewer?job_id=388218664&repo=autoland&lineNumber=1797
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Comment 12•2 years ago
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Comment 13•2 years ago
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Backed out changeset f67c8298a104 (bug 1767262) for causing wpt assertion failures in layout/base/PresShell.cpp
Backout link: https://hg.mozilla.org/integration/autoland/rev/c4bac60f5dc5e2ebc5db221ead691b329701aef3
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Assignee | |
Comment 15•2 years ago
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It seems that the problem here is an assertion failure. When forcing the layout of hidden content, layout requests are flushed. These layout requests can, in turn, trigger queries which force the layout of hidden content. We need to take this into account in the code. I've uploaded a new version of the change which does this.
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Comment 16•2 years ago
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Comment 17•2 years ago
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Description
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