[Webkit-unassigned] [Bug 130582] New: [CSS Blending]Wrong color result for basic blend modes

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=130582

           Summary: [CSS Blending]Wrong color result for basic blend modes
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: Unspecified
        OS/Version: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: CSS
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: rosca at adobe.com
                CC: WebkitBugTracker at adobe.com


Created an attachment (id=227417)
 --> (https://bugs.webkit.org/attachment.cgi?id=227417&action=review)
Sample for 'difference' mode results 

According to the spec[1], the 'difference' blend mode should be computed using this formula: B(Cb, Cs) = | Cb - Cs |.
For example: Fuchsia difference Aqua = Yellow

The result in webkit is different than Yellow. On retina display it's a pale yellow rgb(204, 214, 0), but on non-retina displays, the result is a pale green rgb(0, 190, 0).

The behaviour is the same for both accelerated and non-accelerated blending. I did not test for other blend modes than difference (TBD).

[1] http://dev.w3.org/fxtf/compositing-1/#blendingdifference

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.