Bug 87494

Summary: Body scrollWidth() and scrollHeight() should be page scale-invariant
Product: WebKit Reporter: John Knottenbelt <jknotten>
Component: DOMAssignee: John Knottenbelt <jknotten>
Status: RESOLVED FIXED    
Severity: Normal CC: eric, jamesr, skyostil, webkit.review.bot
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on: 87700    
Bug Blocks:    
Attachments:
Description Flags
Patch
none
Patch none

John Knottenbelt
Reported 2012-05-25 05:59:21 PDT
RenderView::documentRect() is calculating the "scaled" document rect by applying the current transformation matrix to the unscaledDocumentRect() and then returning the rounded-out IntRect result. This rounding out is incorrect because it allows the scaled rectangle to represent an area that is not actually covered by the document. This is evidenced by the document.body.scrollWidth() and document.body.scrollHeight() changing under page scale factor when they are expected to remain invariant.
Attachments
Patch (5.95 KB, patch)
2012-05-25 06:04 PDT, John Knottenbelt 		no flags
DetailsFormatted DiffDiff
Patch (6.45 KB, patch)
2012-05-25 06:36 PDT, John Knottenbelt 		no flags
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
John Knottenbelt
Comment 1 2012-05-25 06:04:53 PDT
Created attachment 144054 [details] Patch
John Knottenbelt
Comment 2 2012-05-25 06:36:53 PDT
Created attachment 144060 [details] Patch
Sami Kyostila
Comment 3 2012-05-25 06:51:53 PDT
For posterity, the effect of this bug is being able to scroll a page one pixel beyond the actual content dimensions at some page scale factors. With the Chromium compositor this causes a red band to be shown to the right and bottom of the page.
James Robinson
Comment 4 2012-05-25 14:37:48 PDT
Comment on attachment 144060 [details] Patch Rounding for teh loss! R=me.
WebKit Review Bot
Comment 5 2012-05-25 14:49:09 PDT
Comment on attachment 144060 [details] Patch Clearing flags on attachment: 144060 Committed r118569: <http://trac.webkit.org/changeset/118569>
WebKit Review Bot
Comment 6 2012-05-25 14:49:13 PDT
All reviewed patches have been landed. Closing bug.
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