Red Hat Bugzilla – Bug 470704
Hinting problems with default Sans font
Last modified: 2008-11-09 16:25:20 EST
Created attachment 322983 [details]
Cropped screenshot of Firefox search box
Description of problem:
There seems to be some strange hinting on certain letter combinations for the Sans font in Fedora 9. This happens in the URL bar and Search box in Firefox, but it probably happens in other applications too. See the screenshots attached.
Version-Release number of selected component (if applicable):
dejavu-fonts-2.24-3.fc9.noarch (I don't know if the default 'Sans' is DejaVu or if 'Sans' is from another package)
Steps to Reproduce:
1. Type the letters 'fi' into the search box in Firefox
Fonts are strangely hinted, as in the screenshot attached.
Kerning and hinting should be consistent.
Created attachment 322984 [details]
Enlarged region of font, with added colour to highlight strange hinting
That's the fi ligature. I don't think it's Freetype using that ligature, but something higher in the stack, for example Qt 3 applications don't use it, Qt 4 apps do. In Firefox's case, it's probably Pango.
But I suspect the real problem is that the font appears to come with a broken fi ligature.
Thanks for the quick response. I wasn't really sure what component to assign this bug to; feel free to reassign it somewhere more appropriate.
I'll let Behdad do that because I'm not really sure what the right component is here (but I suspect it's either dejavu-fonts or pango).
The font itself is fine. However it has to rely on hinting to make sure f and f ligatures are resized consistently at small sizes. Since we don't use upstream hints for evil patent reasons, the problem is in our freetype/pango autohinting logic.
And yes this bug is highly user-visible and very annoying.
You're right, this is the autohinter's fault. If I turn the hinting off entirely, I get unusably blurry fonts, but the ligatures don't look misplaced. So freetype is actually the correct component to file this against (though disabling the ligatures in Pango and Qt 4 might also be a solution, we've done well for years without them, e.g. Qt 3 never used them).
Turns out we already have a bug filed about this, Nicolas just reassigned it to freetype.
*** This bug has been marked as a duplicate of bug 368561 ***