Bug 234997

Summary: Basic color with alpha doesn't match other browsers on non-sRGB monitors
Product: WebKit Reporter: Sam Weinig <sam>
Component: CSSAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: simon.fraser, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Other   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Test using boxes
none
Test using boxes
none
Test using boxes
none
Test using rgb() instead none

Sam Weinig
Reported 2022-01-07 17:59:26 PST
The test css/css-color/t425-hsla-basic-a.xht is failing due to some issue with how we handle hsla() colors. With a simpler test that doesn't use text, it is easier to see that we don't match other browsers.
Attachments
Test using boxes (1007 bytes, application/xhtml+xml)
2022-01-07 18:00 PST, Sam Weinig 		no flags
Details
Test using boxes (1007 bytes, text/html)
2022-01-07 18:00 PST, Sam Weinig 		no flags
Details
Test using boxes (400 bytes, text/html)
2022-01-07 18:02 PST, Sam Weinig 		no flags
Details
Test using rgb() instead (458 bytes, text/html)
2022-01-07 18:10 PST, Sam Weinig 		no flags
Details
Show Obsolete (2) View All Add attachment proposed patch, testcase, etc.
Sam Weinig
Comment 1 2022-01-07 18:00:02 PST Comment hidden (obsolete)
Sam Weinig
Comment 2 2022-01-07 18:00:57 PST Comment hidden (obsolete)
Sam Weinig
Comment 3 2022-01-07 18:02:42 PST
Created attachment 448655 [details] Test using boxes
Sam Weinig
Comment 4 2022-01-07 18:10:21 PST
Created attachment 448656 [details] Test using rgb() instead
Sam Weinig
Comment 5 2022-01-07 18:10:54 PST
Don't think this is hsla() related. But rather something about how we draw.
Sam Weinig
Comment 6 2022-01-07 18:39:58 PST
Looks like this is likely due to using the display colorspace as our working color space for our CGContextRefs. As such, this is not a problem on sRGB displays. We should try to see if we can use extended-srgb as we do on iOS, but it will likely be a bit costly due to the lack of a dedicated scaler. But it is an experiment worth doing.
Radar WebKit Bug Importer
Comment 7 2022-01-14 18:00:18 PST
<rdar://problem/87627670>
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