Bug 58267

Summary: [CG] drawImage with a subimage bleeds pixel data at borders
Product: WebKit Reporter: Matthew Delaney <mdelaney7>
Component: CanvasAssignee: Matthew Delaney <mdelaney7>
Severity: Normal CC: cmarrin, mdelaney7, simon.fraser
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: PC   
OS: OS X 10.5   
Description Flags
Patch mitz: review+

Description Matthew Delaney 2011-04-11 14:13:36 PDT
I'm attaching a testcase that shows the issue. It takes a very pixelated small image of white/orange pixels and does a drawImage with a source width/height of 1. The whole canvas should be uniformly one color. It was previously thought that non-"high"/"default" interpolation qualities in CG would not bleed pixel data from the source, but this appears to not be the case.

The fix is to have the useSubImage portion of ImageCG be used all the time. Uploading this patch now.
Comment 1 Matthew Delaney 2011-04-11 14:15:56 PDT
Created attachment 89086 [details]
Comment 2 Matthew Delaney 2011-04-11 14:36:29 PDT
Created attachment 89092 [details]
Comment 3 mitz 2011-04-11 14:48:47 PDT
Comment on attachment 89092 [details]

r=me if you replace the tabs in the test case with spaces
Comment 4 Matthew Delaney 2011-04-11 15:31:20 PDT
Committed r83521: <http://trac.webkit.org/changeset/83521>