Bug 31283

Summary: position:fixed and transform on same element breaks fixed behavior
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: Layout and RenderingAssignee: Simon Fraser (smfr) <simon.fraser>
Status: CLOSED FIXED    
Severity: Normal CC: eric, hausmann, jamesr, mitz
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Mac   
OS: OS X 10.5   
Bug Depends on:    
Bug Blocks: 36652    
Attachments:
Description Flags
Testcase
none
Patch
mitz: review-
Revised patch
none
Patch mitz: review+

Simon Fraser (smfr)
Reported 2009-11-09 19:36:33 PST
Created attachment 42844 [details] Testcase If an element has both position:fixed and a transform, then it behaves as if it's absolutely positioned. I think the fixed positioning should take effect, and then the transform.
Attachments
Testcase (574 bytes, text/html)
2009-11-09 19:36 PST, Simon Fraser (smfr) 		no flags
Details
Patch (9.78 KB, patch)
2010-01-05 12:39 PST, Simon Fraser (smfr) 		mitz: review-
DetailsFormatted DiffDiff
Revised patch (9.88 KB, patch)
2010-01-05 17:11 PST, Simon Fraser (smfr) 		no flags
DetailsFormatted DiffDiff
Patch (28.68 KB, patch)
2010-01-12 15:23 PST, Simon Fraser (smfr) 		mitz: review+
DetailsFormatted DiffDiff
Show Obsolete (2) View All Add attachment proposed patch, testcase, etc.
Simon Fraser (smfr)
Comment 1 2010-01-05 12:39:22 PST
Created attachment 45920 [details] Patch
mitz
Comment 2 2010-01-05 14:47:59 PST
Comment on attachment 45920 [details] Patch > @@ -982,9 +984,14 @@ void RenderBox::mapAbsoluteToLocalPoint(bool fixed, bool useTransforms, Transfor > if (style()->position() == FixedPosition) > fixed = true; > > + bool isFixedPos = style()->position() == FixedPosition; > bool hasTransform = hasLayer() && layer()->transform(); > - if (hasTransform) > - fixed = false; // Elements with transforms act as a containing block for fixed position descendants > + if (hasTransform) { > + // If this box has a transform, it acts as a fixed position container for fixed descendants, > + // and may itself also be fixed position. So propagate 'fixed' up only if this box is fixed position. > + fixed &= isFixedPos; > + } else > + fixed |= isFixedPos; This doesn’t look right.
Simon Fraser (smfr)
Comment 3 2010-01-05 17:11:57 PST
Created attachment 45943 [details] Revised patch
Eric Seidel (no email)
Comment 4 2010-01-12 14:57:32 PST
This patch is missing the binary data, which is why it's failing to apply correctly. Note that "webkit-patch upload" or "webkit-patch post" or "webkit-patch post-commits" all know how to generate git diff --binary patches correctly so that the bots will be able to property process them. :)
Simon Fraser (smfr)
Comment 5 2010-01-12 15:23:02 PST
Created attachment 46404 [details] Patch
mitz
Comment 6 2010-01-12 16:11:04 PST
Comment on attachment 46404 [details] Patch > + EPosition position; > + if ((position = renderer()->style()->position()) == FixedPosition) { > + if (!ancestorLayer || ancestorLayer == renderer()->view()->layer()) { Please just initialize position first, then do a single if statement: if (position == FixedPosition && (!ancestorLayer || ancestorLayer == renderer()->view()->layer())) { … r=me
Simon Fraser (smfr)
Comment 7 2010-01-12 18:08:42 PST
http://trac.webkit.org/changeset/53173
Simon Hausmann
Comment 8 2010-03-26 08:43:32 PDT
cherry-pick-for-backport: <r53173>
Simon Hausmann
Comment 9 2010-03-26 08:44:04 PDT
Revision r53173 cherry-picked into qtwebkit-2.0 with commit 08dfb1202a63ed6d24be50484e3fbf8bbb9697a4
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