Hi everyeone.
First of all, I marked the topic as IMPORTANT because I believe it is. The issue I'm reporting here is a major problem and I've been working on it for a whole week trying almost everything on the net related to the subject. I hope you guys will help me because this is driving me insane. Here we go...
For a while, I used the latest Opera version on my Fedora Core 4 box with GNOME ONLY. I was using the shared-qt version and everything was perfect. Opera did use the fonts I asked it to use from my Gnome Control Panel (Tahoma 8px for menus). I think Fedora Core is so polished that it did tell QT to use my preferences.
But not so long ago, I decided to install KDE. I did nothing else than installing KDE and set my font preferences exactly like in Gnome. Same QT version (3.3.4) and same everything. But when I launched Opera, I was so surprised that all the menus font were SO SMALL (about 4-5px). Just to be sure, I did check in the Opera font preferences panel to see if something changed, but no: still using Tahoma 8px for menus.
My first reaction was to go back in Gnome (because I still have Gnome on that box, like I said, I just installed KDE, nothing else changed) to see if my Opera was OK in Gnome. I was so damn surprised that it was not! All the menus font were so small just like in KDE. Conclusion? Installing KDE did change something somewhere and that screwed up my Opera.
From that moment, I went back to KDE. I told myself I had to find a fix for this. The first thing I tried was to try that --style default command line parameter I've seen everywhere on the internet that is supposed to fix most problems related to Opera and QT/KDE themes. Didn't help.
Then I got qtconfig to see if there was something wrong with QT. No problem here: QT was using Tahoma 8px for global font.
From that moment, I decided to uninstall Opera, deleted ~/.opera and reinstall it again. Didn't help. I did it again but with the static-qt version just to be sure: Didn't help. This was getting annoying.
After a while, I decided to go back in the Opera font preferences panel to change the menus font size to something else. I realized that changing the font size to 11px looked exactly like 8px should normally do. This was strange because I realized that the problem only concerned font preferences for interface stuff (like menus): font preferences used to display web sites were not affected.
So I concluded that the problem was that something in KDE changed something that would not display fonts correctly in Opera. For a given size, it would display it way smaller than it should. Like I said, to get something looking like 8px, I had to pick up 11px in Opera.
So I just remembered that there was a problem with KDE dpi settings (I don't know if it was fixed or not). I read somewhere that KDE used 75dpi everywhere. Then, I did the math and I realized that the ratio between 11px and 8px was similar to 96dpi and 75dpi. Oh did I forget to mention that in xorg.conf, I setted my dpi to 96? Anyway that doesn't matter much because I tried without it and no luck. And it doesn't make much sense anyway because since I installed KDE, Opera do have the same problem in Gnome as well so unless Opera is now using a KDE library (that I didn't find using 'ldd opera') this shouldn't be a problem.
So I'm here now and the problem is still waiting for a solution. I hope you guys know one because this is driving me insane. Thank you.
PS: I tried turning on and off all setttings related to font preferences in opera6.ini (yes the file is still named opera6.ini in latest opera (8.51)) and again, that didn't help.