RESOLVED FIXED 218645
[TextureMapper] The edges of blur backdrop-filter look gradient tranparent 
https://bugs.webkit.org/show_bug.cgi?id=218645
Summary [TextureMapper] The edges of blur backdrop-filter look gradient tranparent
Fujii Hironori
Reported 2020-11-05 20:59:43 PST
Created attachment 413397 [details] test case [TextureMapper] blur backdrop-filter doesn't have correct outsets The inside of box should be solid gray.
Attachments
test case (697 bytes, text/html)
2020-11-05 20:59 PST, Fujii Hironori 		no flags
Details
[Screenshot] GTK port (17.11 KB, image/png)
2020-11-09 22:15 PST, Fujii Hironori 		no flags
Details
Patch (8.84 KB, patch)
2020-11-09 23:05 PST, Fujii Hironori 		no flags
DetailsFormatted DiffDiff
test case 2 (1.39 KB, text/html)
2020-11-10 16:36 PST, Fujii Hironori 		no flags
Details
WIP patch (1.64 KB, patch)
2020-11-15 18:12 PST, Fujii Hironori 		no flags
DetailsFormatted DiffDiff
Patch (8.19 KB, patch)
2020-11-15 20:11 PST, Fujii Hironori 		no flags
DetailsFormatted DiffDiff
Show Obsolete (2) View All Add attachment proposed patch, testcase, etc.
Fujii Hironori
Comment 1 2020-11-09 22:07:52 PST
css3/filters/backdrop/blur-input-bounds.html is a test case that is added by Bug 146215.
Fujii Hironori
Comment 2 2020-11-09 22:15:49 PST
Created attachment 413665 [details] [Screenshot] GTK port
Fujii Hironori
Comment 3 2020-11-09 23:05:30 PST
Created attachment 413669 [details] Patch
Miguel Gomez
Comment 4 2020-11-10 04:55:34 PST
I need to dig a bit deeper in the code to properly understand how backdrop-filters work and how they should work. I'll devote some time to this. In the meanwhile, Fujii, did you see bug 217476? Concretely this test page https://hacktivis.me/tmp/webkit-backdrop-filter-header.xhtml Checking against Chrome I see 2 things: - The weird effect just below the rectangle, that happens when mixing the rectangle shadow with the text. Seems that instead of a uniform blur shadow, the shadow is using the underlying text to be calculated, as is it was a blur of the text. This is probably a different bug than this one. - There's a small part at the left and top of the rectangle where the blur is not applied. It's easily visible if you scroll the text. This seems something similar to the issue you're trying to fix here, but it happens with your patch as well. What do you think?
Fujii Hironori
Comment 5 2020-11-10 12:24:54 PST
I didn't know the bug. Thank you. The second problem is that backdrop-filter block is placed in the top left corner but the root layer doesn't render the outside of screen into the intermediate surface. I should take the same extrapolating approach like Cocoa port. The first problem is interesting, but I don't figure out. I will check it.
Fujii Hironori
Comment 6 2020-11-10 16:36:21 PST
Created attachment 413757 [details] test case 2
Radar WebKit Bug Importer
Comment 7 2020-11-12 21:01:40 PST
<rdar://problem/71356999>
Fujii Hironori
Comment 8 2020-11-15 18:12:53 PST
Created attachment 414188 [details] WIP patch
Fujii Hironori
Comment 9 2020-11-15 20:11:30 PST
Created attachment 414190 [details] Patch
EWS
Comment 10 2020-11-16 00:20:02 PST
Committed r269837: <https://trac.webkit.org/changeset/269837> All reviewed patches have been landed. Closing bug and clearing flags on attachment 414190 [details].
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