Bug 83630 – Border-image rendering breaks with non-integer page zoom

• Component: Layout and Rendering
• Status: UNCONFIRMED

[Dan Weatherford]

Created attachment 136560 [details]
Test case

See the attached test case. At page zoom 1 (not zoomed in), the tab draws a white background; at noninteger page scales, the tab does not draw a background.

I suspect that this is a rounding error that was revealed by the behaviour change in r104851.

Repro steps, tested on Chrome 19.0.1084.15 on Mac OS X 10.6.8:

0) if necessary: Reset the browser to the default 1x page zoom.

1) Load the attached test case. The page should paint a complete tab box -- left and right edges with a white fill center.

2) Increase the page zoom (command-plus on Mac). For non-integer page zoom values, the white center of the tab disappears, leaving only the left and right borders.

3) Continue increasing the page zoom until you get to 2x -- the tab center reappears. On Chrome Mac, there are 4 non-integer page zoom steps between 1x and 2x.

[Radar WebKit Bug Importer]

<rdar://problem/11228207>

[Dan Weatherford]

Created attachment 136737 [details]
Test case 2

For this second test case, the border edges disappear. Follow the same repro steps as the first test case (observe at default 1x page zoom and after zooming in)

[Pam Griffith]

Created attachment 142066 [details]
Test case that also looks fine at 150% as well as 100% and 200%

This is happening for me also. I am on Chrome 20.0.1132.3 on Windows 7.

I am attaching a third test case that looks correct at 100%, 150%, and 200%. The previously attached test cases do not look correct to me at 150%.

[Zack Weinberg]

Also reproducible with Chromium 18.0.1025.168 (Webkit 535.19) and Epiphany 3.4.1 (Webkit 535.22+) on Linux.