Bug 112454

Summary: RenderBox::backgroundIsKnownToBeOpaqueInRect is wrong for <body> element under certain conditions
Product: WebKit Reporter: Alok Priyadarshi <alokp>
Component: Layout and RenderingAssignee: Alok Priyadarshi <alokp>
Status: RESOLVED FIXED    
Severity: Normal CC: jamesr, koivisto, simon.fraser, vangelis
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 70634    
Attachments:
Description Flags
Test case none

Alok Priyadarshi
Reported 2013-03-15 10:32:25 PDT
Created attachment 193334 [details] Test case RenderBox::backgroundIsKnownToBeOpaqueInRect looks at the CSS background to determine if the RenderBox is opaque. This works for all elements except the <body> element if: 1. The <body> element is composited 2. The <html> element does not have a background In this case <body> background is not painted and you can see through any elements under the <body>. In the attached example <body> border is painted over the underlying <div>, but the background is not. In this case <body> element is not opaque. As soon as you add a background to the <html> element, the body background gets painted and becomes opaque.
Attachments
Test case (354 bytes, text/html)
2013-03-15 10:32 PDT, Alok Priyadarshi 		no flags
Details
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Antti Koivisto
Comment 1 2013-03-19 15:47:53 PDT
I don't see any regression with the test case. Are there some additional steps to reproduce?
Alok Priyadarshi
Comment 2 2013-03-19 16:52:02 PDT
(In reply to comment #1) > I don't see any regression with the test case. Are there some additional steps to reproduce? I did not find it straightforward to create a "repaint" test case. The attached html page is not really a test case, but rather an example where <body> render-box should not be considered opaque. Please see the latest patch for https://bugs.webkit.org/show_bug.cgi?id=70634. In particular the function skipBodyBackground() and two test cases - body-background-painted and body-background-skipped. Without skipBodyBackground() logic, body-background-skipped will fail.
Alok Priyadarshi
Comment 3 2013-03-22 10:15:41 PDT
This was fixed in r146531. http://trac.webkit.org/changeset/146531
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