112454 2013-03-15 10:32:25 -0700 RenderBox::backgroundIsKnownToBeOpaqueInRect is wrong for <body> element under certain conditions 2013-03-22 10:15:41 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Unspecified Unspecified RESOLVED FIXED P2 Normal --- 70634 1 alokp alokp jamesr koivisto simon.fraser vangelis oldest_to_newest 856084 0 193334 alokp 2013-03-15 10:32:25 -0700 Created attachment 193334 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. 858820 1 koivisto 2013-03-19 15:47:53 -0700 I don't see any regression with the test case. Are there some additional steps to reproduce? 858873 2 alokp 2013-03-19 16:52:02 -0700 (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. 861618 3 alokp 2013-03-22 10:15:41 -0700 This was fixed in r146531. http://trac.webkit.org/changeset/146531 193334 2013-03-15 10:32:25 -0700 2013-03-15 10:32:25 -0700 Test case underbody.html text/html 354 alokp PCFET0NUWVBFIGh0bWw+DQo8aHRtbD4NCjxoZWFkPg0KPHN0eWxlPg0KICBib2R5IHsNCiAgICBi YWNrZ3JvdW5kLWNvbG9yOiBibHVlOw0KICAgIHdpZHRoOiA0MDBweDsNCiAgICBoZWlnaHQ6IDQw MHB4Ow0KICAgIGJvcmRlcjogc29saWQgNXB4IHJlZDsNCiAgfQ0KICAjdW5kZXJib2R5IHsNCiAg ICBwb3NpdGlvbjogZml4ZWQ7DQogICAgei1pbmRleDogLTE7DQogICAgd2lkdGg6IDUwMHB4Ow0K ICAgIGhlaWdodDogNTAwcHg7DQogICAgYmFja2dyb3VuZC1jb2xvcjogZ3JlZW47DQogIH0NCjwv c3R5bGU+DQo8L2hlYWQ+DQo8Ym9keT4NCjxkaXYgaWQ9InVuZGVyYm9keSI+PC9kaXY+DQo8L2Jv ZHk+DQo8L2h0bWw+