Avoid subpixel antialiasing differences in reftest select-3.html
Categories
(Core :: Layout: Positioned, task)
Tracking
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| Tracking | Status | |
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| firefox101 | --- | fixed |
People
(Reporter: dholbert, Assigned: dholbert)
Details
Attachments
(2 files)
reftest select-3.html has an extremely complex fuzzy-failure annotation right now -- and in fact it's not-complex enough, because the test still triggers an unexpected failure with a different amount of fuzziness on my local machine.
Looking at the test failure in reftest-analyzer, we're failing because the testcase has subpixel (colorful) antialiasing, whereas the reference case has grayscale antialiasing (presumably because it uses position:fixed).
Per bug 1763411 comment 8, this is not-entirely-surprising; subpixel AA gets enabled/disabled depending on whether WebRender can be absolutely sure there's an opaque background behind the text (and the heuristics that it uses to do this aren't perfect).
Anyway; we should fix the test to avoid tripping this unimportant-to-the-thing-actually-being-tested rendering difference between the testcase and reference case, so that we don't have to maintain a bespoke platform-specific fuzzy failure annotation.
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Comment 1•2 years ago
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I'm going to make two changes here:
(1) create a copy of the test that uses transparent text (so that it won't trigger subpixel antialiasing). To the extent that this test is screening for positioning differences between position:absolute vs. position:fixed select widgets, this new test will continue to screen for that.
(2) adjust select-3-ref.html to just be position:absolute. This lets us continue to test how the testcase looks (text-and-all), vs. a reference case that is still different/simpler-in-structure. (The testcase has an extra position:relative div around the abspos thing, which I think is the real important difference between the two in terms of testing the original bug.)
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Comment 2•2 years ago
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Comment 3•2 years ago
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This should still serve as a good reference case for select-3.html, since it's
still simpler-in-structure than that testcase.
To the extent that the testcase really does want to test positioning of select
elements with position:absolute vs. position:fixed (I'm not sure if it does,
but just in case it does): we still have coverage for that, via the new copy of
this reftest called "select-4.html" added in the previous patch in this series.
Depends on D144225
Pushed by dholbert@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/1bda7c512831 part 1: Create a copy of reftest "select-3.html" with transparent text, to avoid antialiasing-related fuzzy failures. r=hiro https://hg.mozilla.org/integration/autoland/rev/58432e7f0940 part 2: Change reference case select-3-ref.html to use position:absolute instead of fixed, to avoid fuzzy failures due to antialiasing differences. r=hiro
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Comment 5•2 years ago
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| bugherder | ||
https://hg.mozilla.org/mozilla-central/rev/1bda7c512831
https://hg.mozilla.org/mozilla-central/rev/58432e7f0940
Description
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