Description of problem: Images and links displayed in Firefox shift left or right one pixel when the mouse cursor passes over them. This does not happen on my previous version of Fedora. Possibly related problem is that the display of fonts looks horrible compared to other GTK+ apps. Every looks crisp on my display except typefaces rendered in Firefox, which look blurry and shift around unexpectedly as the mouse cursor moves past. Don't know if it's a bug in Firefox or GTK+. Version-Release number of selected component (if applicable): Firefox 2.0.0.9 How reproducible: Very. Happens 100% of the time. Steps to Reproduce: 1. View a web page with images and text links. 2. Move mouse cursors over them. 3. Cringe in horror at the annoying shifting. Actual results: Images and links shift back and forth by 1px. Typefaces are render badly. Expected results: Images and links remain where the web designers put them. Fonts should look nice and clear like other GTK+ apps. Additional info: I'll try to get some screen capture that illustrate the problem and upload them shortly.
I ran across a report of a similar problem with Firefox on Kubuntu, though it involves vertical shifts in images/text in the Firefox UI itself rather than horizontal shifts in web page content. If a GTK+ problem is responsible, though, this bug report might be related. http://ubuntuforums.org/showthread.php?t=118750
Unfortunately, it doesn't appear possible to create a screen capture of the problem. Even though there's a clear visual shift in images and text on the live browser, the before and after screen capture are always identical. Just to make sure I'm not crazy or hallucinating, I've had several other people look at the phenomenon and we all agree on what we're seeing. Perhaps the inability to do a screen capture of the issue reveals something about the cause?
Can you go to System>Preferences>Look&Feel>Appearance and in the fonts tab, click on Details, and make sure you have 96dpi? Other than that suggestion, I have no idea as to how to possibly begin debugging this. Everything appears normal for me; I don't see any shifting on mouseover on any pages....
It currently reads 100dpi. I haven't adjusted it. 100dpi must be the value it determined during the install, which seems correct. It's a Viewsonic VP2030b with a 16.1" x 12.1" panel that has 1600x1200 native resolution. The video card is an ATI RV380 (Radeon X600) using the radeon driver. The desktop and all the other GTK+ programs I've tried look beautiful. It's only Firefox that has problems. Just for kicks, I've manually adjusted it to 96dpi. Interestingly, I could see the fonts shrinking on everything but Firefox as I adjusted it. Guess I'll have to shutdown Firefox and restart to get it to pick the change. I'll post the results momentarily.
After restarting Firefox with the resolution set to 96dpi, the shifting effect seems to have vanished. The type still looks a little fuzzy compared to other GTK+ programs but at least it's not jumping around on the page. So, this seems like a suitable work-around for now. The weird thing is that my Laptop, which also runs Fedora, doesn't have this problem. It has a 1920x1200 display that's 140dpi. Does this mean there's a bug that only affects 100dpi screens? On the other hand, my Laptop has nVidia graphics hardware and uses the nv driver. Maybe the bug only affects 100dpi + radeon driver setups?
Can I get output of the command xdpyinfo |grep resolution please?
[rsr@rodan ~]$ xdpyinfo | grep resolution resolution: 100x100 dots per inch And, just in case it's helpful: [rsr@rodan2 ~]$ xdpyinfo | grep dimensions dimensions: 1600x1200 pixels (408x306 millimeters)
The DPI should not be set to anything other than 96dpi. See http://log.ometer.com/2007-11.html This is not a bug in X or Firefox or anything. Just the defaults for GNOME which is covered elsewhere in upstream GNOME.
While I agree that setting the display DPI to 96 eliminates the shifting, the display is not a 96dpi device. Setting the DPI to an incorrect value sounds more like a work-around than a good default practice. As display resolutions continue to improve, this is likely to crop up more often. In this case, 96 is close enough to the correct value of 100 that it's not a problem. But, as I noted above, my laptop has a 140dpi display, so setting it to 96dpi would introduce something like a 30% error in the scales of everything displayed (at least by my understanding of how this stuff works).
caillon is right. This bug is real, but most certianly won't be fixed by the Red Hat support. If you want to fight for fixing of this bug, then please do so upstream. I would suggest https://bugzilla.mozilla.org/show_bug.cgi?id=20802, but there is a lot of other bugs related to this issue in the upstream bugzilla. https://bugzilla.mozilla.org/buglist.cgi?query_format=specific&order=relevance+desc&bug_status=__open__&content=96dpi
Thanks! That makes sense actually, since all the other GTK+ apps look fine when the actual dpi is used. I'll take a look at the mozilla bug.