rendering of characters in Firefox (periodic problem)

[Termo]

I have a weird issue in Firefox on Ubuntu 10.10, and sadly it's a periodic mistake that I don't know how to initiate...

Sometime in firefox some of the characters seems not fully rendered, and as I recall it can also happen in menu fonts sometimes. In the attached screen-shot you can see that it's the a character that has the problem - but only for one font type or? But I have seen this with most characters I think - and as stated this happens randomly.

For instance right now I looked again in the tab in firefox where I just 5 minutes ago did the screen-shot and now all characters are correct?? I have tried to reload or even restart firefox when it occurs, but this is now guaranty for a solution...

Any ideas of what courses this and how I can stop it from happening. When it happens it makes many homepages unreadable

Best regards Rasmus

[Termo]

[Update]
Actually now 5 minutes later again it's now the "y" character in the same homepage?!?!?

[digismack]

I am having the same problem. I have noticed it in Firefox (3.6.13) and in the console when using nano or similar text editors. I can have the same website open in Firefox and Chrome.. Firefox renders the font with the problem at hand, Chrome renders the website fine. I am a web developer / designer so I can't just not use Firefox.

I have ran memtest86+ and it completed with no errors. Anyone able to help us out here? Would be greatly appreciated.

(Edit: Updated error info.)

[Termo]

*BUMP*

It's really annoying, there must be someone out there with a hint or an idea on how to find what is causing this...

[Krytarik]

Does this also happen with a fresh user profile?

[Termo]

Thank you for suggestion - I have myself thought of completely remove firefox settings folder in home and then slowly migrate settings back...

Anyway, just made a new user, and now already in the window title the "o"s this time was partly rendered. So this issue is not to do with firefox explicit but general character rendering. This also goes find in hand with my observation from firefox that when making fonts bigger or smaller (ctrl + or -) would make the issue disappear in the other sizes, but re-enter when back to normal size.

Switching user back shows no rendering error in my normal user account. Switching back again still shows the rendering error...


So with this new information where to look now??

[Krytarik]

Try fiddling with the options in "System -> Preferences -> Appearance -> Fonts -> Details".

[Termo]

I have now been playing around a bit with fonts settings in Firefox to find out where and what changes this...

First I thought that disabling "Allow pages to choose their own fonts" would make the difference, but then the rendering error also came when I had my settings to control fonts on pages.

Then I thought it only had to do with Serif fonts, but that apparently just depends on what I choose in "proportional", which by standard is for Serif in firefox. When I changed this to sans-serif the error came again at some point...

As the two types of uploaded screenshots show does the error change when I change font - but these two screenshots also show that it happens both for the Droid and the DejaVu font. So not font specific apparently

[Krytarik]

I thought it was already clear to you, that the issue doesn't have anything to do with Firefox, since it also occurs in the window titles of Nautilus, the previously posted screenshots.

What about the general font rendering settings I mentioned? Though I doubt this would fix it.

[Termo]

True that the error is not specific to firefox - but I only very rarely see it in the general fonts used in Ubuntu. So when I saw it in Firefox again I tried to get some knowledge into if it was specific for any specific font... But that does not seem to be the case.

Yes I tried to look into the Appearance but the only difference I saw to the Ubuntu install I have on a usb-HDD was the 'Document font' that I changed to Sans as on the usb. But the problem still came back in Firefox.