Bug 9955

Summary: Colors scaled from [0, 1] range to [0, 255] incorrectly
Product: WebKit Reporter: Sam Weinig <sam>
Component: WebCore Misc.Assignee: Sam Weinig <sam>
Status: RESOLVED FIXED    
Severity: Normal    
Priority: P2    
Version: 420+   
Hardware: Mac   
OS: OS X 10.4   
Attachments:
Description Flags
patch
darin: review+
patch 2 darin: review+

Sam Weinig
Reported 2006-07-16 07:36:23 PDT
In Color.cpp, when a color needs to scaled from the floating-point range of [0.0, 1.0] to the integer range of [0, 255], such as in the HSLA code, the current code is producing an uneven distribution.
Attachments
patch (11.99 KB, patch)
2006-07-16 07:44 PDT, Sam Weinig 		darin: review+
DetailsFormatted DiffDiff
patch 2 (198.43 KB, patch)
2006-07-16 10:32 PDT, Sam Weinig 		darin: review+
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Sam Weinig
Comment 1 2006-07-16 07:44:53 PDT
Created attachment 9490 [details] patch Patch changes scaling behavior and updates Color class to comply with style guidelines.
Darin Adler
Comment 2 2006-07-16 07:53:12 PDT
Comment on attachment 9490 [details] patch Looks good. + float alpha = static_cast<float>(a) / 255.0f; The cast above seems unneeded. + c.setRGB(238, 238, 238); // FIXME: if this is a constant it should be specified as one. I agree that would be nice to fix, but I don't think the FIXME adds much. + const double scaleFactor = nextafter(256.0, +0.0); I think the use of + here on +0.0 is a bit queer. We could have + in front of all our floating point constants but we don't. Looks good, those are minor quibbles. r=me
Sam Weinig
Comment 3 2006-07-16 10:32:20 PDT
Created attachment 9496 [details] patch 2 Fixes darin's quibbles and adds changed tests.
Darin Adler
Comment 4 2006-07-16 15:20:23 PDT
Comment on attachment 9496 [details] patch 2 r=me
Darin Adler
Comment 5 2006-07-31 23:09:24 PDT
Committed revision 15734.
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