307165 - Text position shifts on hover with underline text decoration and opacity less than 1

Status: VERIFIED WORKSFORME

(Core :: Layout: Text and Fonts, defect)

Description

[Brett Donald]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b4) Gecko/20050901 Firefox/1.0+
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b4) Gecko/20050901 Firefox/1.0+

Text position may shift vertically by one pixel when a :hover style adds an
underline text decoration, and the text is only partially opaque. The shift
occurs the first time the :hover is activated after page load, then the new
(incorrect) position remains until the page is refreshed.

The problem is related to font-size -- if you increase or decrease the font size
(Ctrl+ and Ctrl-), the problem is not apparent at some font sizes, at others the
text may move up one pixel, at others it may move down one pixel. It also may be
related to the presence of other page elements; in this case, a select element
with a top margin.

Reproducible: Sometimes

Steps to Reproduce:
1. Load the test case into Firefox
2. Hover over each of red text strings "THE SPAN CONTENS"

Actual Results:  
Most of the spans move down by one pixel as the underline is added, then remain
one pixel out of alignment from then on, until the page is refreshed. (Depending
on the font size, they may not move, or move up one pixel instead.)


Expected Results:  
Text should not move when adding an underline decoration.

Comment 1

[Brett Donald]

Attachment: Test case

Comment 2

[Martijn Wargers (dead)]

I can see the bug also in Mozilla1.7, so no (recent) regression.

Comment 3

[Garrett Murray]

Definitely not recent, has been around for a while... due I believe to twip usage.

We should change severity to normal because I don't think this is a 'trivial'
bug--as more and more people start to use CSS technology, more and more sites
will use the opacity functionality and this bug will be very noticeable.

Comment 4

[j.j.]

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a7pre) Gecko/2007072605 Minefield/3.0a7pre

WFM

Comment 5

[Martijn Wargers (dead)]

Yeah, this is worksforme too, with current trunk build.
Brett, could you verify this is worksforme with current trunk build? Thanks.
http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk/

Comment 6

[Brett Donald]

Agreed -> resolving WFM