In the following test cases: css3/zoom-coords.xhtml svg/zoom/page/zoom-zoom-coords.xhtml the text height is one pixel too high. The text height is set to 12px (using the Ahem font), and showed in scaled coordinates. For example, when the scale is 50%, the expected text height is 6. These test cases pass on all platforms except for GTK. On GTK, the function getBoundingClientRect indicates the text height to be 6.5 instead of 6, and 13 instead of 12.
For the time being, the two failing tests are listed in platform/gtk/Skipped This is done in bug 50314. The patch for 50314 should be undone when this bug is fixed.
Thanks for opening this bug. Does this only affect GTK+?
(In reply to comment #2) > Thanks for opening this bug. Does this only affect GTK+? I assume that's the case, because I did not see other failures elsewhere. The platforms where I run tests myself are webkit-mac and chromium-linux.
Created attachment 75279 [details] Reduced test case Actually, it's not even necessary to use the CSS3 zoom attribute to reproduce the failure. The first SVG test ("svg1") in css3/zoom-coords.xhtml is only scaled using ... height="50px" viewBox="0 0 150 100" and it's still failing. It may be possible that it isn't even a zooming issue, after all. I wonder, is the attached test ("text-height.xhtml") passing under GTK?
The patch on bug 12448 fixes this problem. *** This bug has been marked as a duplicate of bug 12448 ***