I'm using current DejaVu fonts from Subversion (days before 2.9 release). Cyrillic letters look pretty bad in DejaVu Sans Bold at low sizes (10 and below). The screenshot shows DejaVu Sans Bold at size 10 (96dpi) with RGB subpixel rendering (which shouldn't be relevant - it just makes it easy to see the problem on an LCD). It's obvious that sha (ш) is lower than scha (щ), and pe (п) is lower than o (о). er (р) has some strange kink near in the top left corner. It's supposed to look exactly like Latin "p". Furthermore, all Cyrillic capital letters are higher than the Latin counterparts. The small letters are bigger too, and they are also unaligned among themselves.
Created attachment 6507 [details] test screenshot
Are you using the autohinter? The glyphs you talk about are all hinted, and should display much better than in your screenshot, with the bytecode interpreter enabled. Capitals being bigger in Cyrillic shouldn't happen either, since the ones that look like Latin capitals are references to the Latin ones, meaning that they are essentially the same glyph, and should render exactly the same. If you are using the autohinter, there is nothing we can do about this. If you use KDE, you can always test by tweaking the hinting style in the fonts settings in kcontrol.
(In reply to comment #2) > Are you using the autohinter? I guess I am. > The glyphs you talk about are all hinted, and > should display much better than in your screenshot, with the bytecode > interpreter enabled. I understand I should have provided more information about my system. It's the current Fedora Development with freetype 2.2.1. I don't know how to control whether the interpreter is enabled. > Capitals being bigger in Cyrillic shouldn't happen > either, since the ones that look like Latin capitals are references to the > Latin ones, meaning that they are essentially the same glyph, and should > render exactly the same. I can see it in the *.sfd files, so it's quite puzzling. I guess the autohinter is working differently on different scripts. > If you are using the autohinter, there is nothing we can do about this. > > If you use KDE, you can always test by tweaking the hinting style in the fonts > settings in kcontrol. There are two hinting related controls in kcontrol. One is "use sub-pixel hinting" and the other is "hinting style". I had the first of them set to RGB and the second to "full". Strangely enough, setting "hinting style" to "none" doesn't disable "use sub-pixel hinting". I guess "hinting style" is related to autohinting and "use sub-pixel hinting" is not. Unfortunately, setting "hinting style" to "none" makes the unwanted color variations of the text too pronounced, and turning off "sub-pixel hinting" makes the text blurry. Turning off anti-aliasing makes the text extremely ugly. And that affects Latin symbols too. I settled for the with blurry text for now (no sub-pixel hinting, style none), but I guess I'm not actually using the hinting from the fonts, or the non-antialiased text would be looking better.
Created attachment 6516 [details] kcontrol with antialiasing disabled, using DejaVu Sans
If you want to enable the real hinting instructions in the font, follow the instructions at https://bugs.freedesktop.org/show_bug.cgi?id=7825 to recompile the FreeType rpm. It's possible that you have to edit your fonts.conf file as well to disable the autohinter.
The link in the above comment points to this bug. It doesn't point to the instructions how to recompile the FreeType rpm. I guess what needs to be done is to enable TT_CONFIG_OPTION_BYTECODE_INTERPRETER in include/freetype/config/ftoption.h. It's not hard to do. Still, it would be nice to have a working link to the "official" instructions here, especially if that page discusses the patent implications.
Oops, that must have been an error while copy-pasting. The correct link is http://cri.ch/linux/docs/sk0017.html
I think freetype is forced to autohint glyphs with own algorithm on your system. On modern system check whether you have the 10-autohint.conf symlink at /etc/fonts/conf.d/ , remove it. Proper check of rendering can be made using ftview program from ft2demos packages. It renders a font independently from X.
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