Bug 67897 - Pixel stop positions for linear-gradient property miscalculated
Summary: Pixel stop positions for linear-gradient property miscalculated
Status: RESOLVED WONTFIX
Alias: None
Product: WebKit
Classification: Unclassified
Component: CSS (show other bugs)
Version: 528+ (Nightly build)
Hardware: Unspecified All
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-09-10 16:41 PDT by John Flatness
Modified: 2012-03-22 15:09 PDT (History)
3 users (show)

See Also:


Attachments
Simple testcase (35 bytes, text/plain)
2011-09-10 16:41 PDT, John Flatness
no flags Details
Simple testcase, 2nd attempt (819 bytes, text/html)
2011-09-10 16:44 PDT, John Flatness
no flags Details

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Description John Flatness 2011-09-10 16:41:37 PDT
Created attachment 106989 [details]
Simple testcase

When using a linear gradient as the background image for an element, stop positions that are specified in pixels are inconsistent.

For a vertically-oriented gradient, the positions change as the height of the element increases. At very large heights, the positions as rendered can be extremely different than the specified values, but even relatively smaller dimensions cause some shifting.

In the 

Confirmed on WebKit r94906 Mac, Safari 5.1 Mac, and countless Chromes and Chromiums on several platforms.
Comment 1 John Flatness 2011-09-10 16:44:53 PDT
Created attachment 106990 [details]
Simple testcase, 2nd attempt

Attaching a URL didn't seem to have the effect I expected.
Comment 2 David Barr 2011-10-05 20:39:04 PDT
Confirmed on Webkit r96763 and Chrome 16.0.901.0 canary.
Comment 3 Mike Lawther 2012-03-21 18:53:09 PDT
We investigated this, and WebCore is passing correct values down to the platform graphics layers.

There appear to be bugs in the linear gradient rasterisers in both CoreGraphics (seen on Safari on Mac 10.6 and 10.7) as well as Skia (for Chrome).

Closing as wontfix, as this is not a bug in WebCore.
Comment 4 David Barr 2012-03-22 15:09:21 PDT
Cross-referenced on the underlying Skia bug:
http://crbug.com/117140