Bug 126653 - Subpixel layout: RenderMultiColumnBlock::computeColumnCountAndWidth() needs flooring.
Summary: Subpixel layout: RenderMultiColumnBlock::computeColumnCountAndWidth() needs f...
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: 528+ (Nightly build)
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: zalan
Keywords: InRadar
Depends on:
Blocks: 126283
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Reported: 2014-01-08 11:59 PST by zalan
Modified: 2014-01-15 13:09 PST (History)
3 users (show)

See Also:

rendering snapshots (93.00 KB, image/jpeg)
2014-01-15 13:07 PST, zalan
no flags Details

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Description zalan 2014-01-08 11:59:43 PST
This is rather similar to bug 126646. We produce an off by one pixel rendering when subpixel is on, though flooring it to CSS pixel would defeat the purpose of subpixel positioning the column content.

m_columnWidth = std::max<LayoutUnit>(0, (availWidth - ((m_columnCount - 1) * colGap)) / m_columnCount);

failed cases:
Comment 1 Simon Fraser (smfr) 2014-01-08 15:26:08 PST
Talk to Hyatt.
Comment 2 zalan 2014-01-15 13:07:43 PST
Created attachment 221301 [details]
rendering snapshots
Comment 3 Radar WebKit Bug Importer 2014-01-15 13:08:31 PST
Comment 4 zalan 2014-01-15 13:09:25 PST
FF(v26) rendering is in-between subpixel off and subpixel on. Prefer current subpixel rendering.