Bug 47157

Summary: CSS 2.1 failure: background-position-001, background-position-002
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: Layout and RenderingAssignee: Dave Hyatt <hyatt>
Status: RESOLVED FIXED    
Severity: Normal CC: ap, hyatt, mitz, simon.fraser
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
URL: http://test.csswg.org/suites/css2.1/20110111/html4/background-position-001.htm
Bug Depends on: 52122    
Bug Blocks: 47141    
Attachments:
Description Flags
background-position-001.htm
none
Patch simon.fraser: review+

Simon Fraser (smfr)
Reported 2010-10-04 21:50:25 PDT
Created attachment 69752 [details] background-position-001.htm These tests fail: html4/background-position-001 fail html4/background-position-002 fail
Attachments
background-position-001.htm (1.24 KB, text/html)
2010-10-04 21:50 PDT, Simon Fraser (smfr) 		no flags
Details
Patch (274.31 KB, patch)
2011-03-10 12:58 PST, Dave Hyatt 		simon.fraser: review+
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Simon Fraser (smfr)
Comment 1 2011-01-08 12:25:38 PST
These tests rely on 'ex' units.
Simon Fraser (smfr)
Comment 2 2011-01-08 12:52:42 PST
We're getting an xHeight of 20 for the Ahem font at 20px, but it seems that the xHeight should be 80% of this <http://hixie.ch/resources/fonts/> CTFontGetBoundingRectsForGlyphs() returns a rect of 0,-4, 20x20, which boundingBox.setY(-boundingBox.bottom()); converts to 0,-16, 20x20 which seems wrong.
mitz
Comment 3 2011-01-08 13:03:07 PST
Right, on Mac OS X, WebKit prefers the height of the lowercase x glyph over the x-height encoded in the font.
Simon Fraser (smfr)
Comment 4 2011-01-08 13:08:33 PST
Ah, the culprit is: // Use the maximum of either width or height because "x" is nearly square // and web pages that foolishly use this metric for width will be laid out // poorly if we return an accurate height. Classic case is Times 13 point, // which has an "x" that is 7x6 pixels. m_xHeight = static_cast<float>(max(CGRectGetMaxX(xBox), -CGRectGetMinY(xBox))); Maybe we should make an exception for the Ahem font?
Simon Fraser (smfr)
Comment 5 2011-01-08 13:16:47 PST
The tests covered by bug 47158 also rely on ex units.
Simon Fraser (smfr)
Comment 6 2011-03-09 17:52:25 PST
Fixed by http://trac.webkit.org/changeset/80662 ?
Dave Hyatt
Comment 7 2011-03-10 12:56:53 PST
*** Bug 47158 has been marked as a duplicate of this bug. ***
Dave Hyatt
Comment 8 2011-03-10 12:57:54 PST
No, not fixed by r80662. Actual patch coming shortly.
Dave Hyatt
Comment 9 2011-03-10 12:58:27 PST
Created attachment 85379 [details] Patch
Simon Fraser (smfr)
Comment 10 2011-03-10 13:04:27 PST
Comment on attachment 85379 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=85379&action=review > Source/WebCore/ChangeLog:5 > + https://bugs.webkit.org/show_bug.cgi?id=47157, CSS2.1 test failures because the ex unit is broken We normally put the bug URL on its own line. > LayoutTests/accessibility/image-map-title-causes-crash-expected.txt:-10 > - 1 > -Requesting the title of an AccessibilityImageMapLink can cause a crash when the map's area element has been removed. > - > -On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". > - > - > -PASS successfullyParsed is true > - > -TEST COMPLETE > - Why did this result go away?
Dave Hyatt
Comment 11 2011-03-10 13:29:37 PST
Fixed in r80755.
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