[Webkit-unassigned] [Bug 103216] New: PNG decode performance: avoid using frame buffer.setRGBA(x, y)

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=103216

           Summary: PNG decode performance: avoid using frame
                    buffer.setRGBA(x,y)
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: Unspecified
        OS/Version: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Images
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: noel.gordon at gmail.com


Writing decoded row pixels to the frame buffer with buffer.setRGBA(x,y) is slow compared to writing direct to the frame buffer. 

I disabled color profiles in the PNG decoder, and instrumented the total decode time and time taken to write row data to the frame buffer.  The amount in ()'s is the percentage of decode time spent writing row data.

http://duke.kenai.com/eco/DukeTreeHuggerSmall.png
           row write time 0.002204
           PNG decode ends 0.016935 (13%)

http://duke.kenai.com/eco/DukeTreeHuggerSmall.png
           row write time 0.022714
           PNG decode ends 0.141308 (16%)

http://trac.webkit.org/browser/trunk/LayoutTests/fast/images/resources/red-at-12-oclock-with-color-profile.png
           row write time 0.001901
           PNG decode ends 0.012777 (14%)

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