Red Hat Bugzilla – Bug 47868
Fonts do not scale with the Xserver DPI setting
Last modified: 2007-04-18 12:34:33 EDT
Description of Problem: The Xserver's dpi setting (as probed by the ddc module or set with the -dpi flag) has no effect on the size of fonts. This is a particular problem when running X in high resolution modes (e.g. 1600x1200) where the dpi can be 135 leading to unreadable fonts. How Reproducible: Every Time Steps to Reproduce: 1. Run "X -dpi n :1 & xterm -display :1". Replace n with a dpi value. 2. Run a program which allows you to view different fonts (e.g. gfontsel or mozilla). Note the size of a large (e.g. 72pt) font. 3. Repeat for different n. Actual Results: The font sizes are identical at different values of n. Expected Results: Changing n from 100 to 150 should result in a noticable increase in the size of a font. Additional Information: Tested with XFree86-4.0.3-5 from 7.1 and 4.03-22 from RawHide with both ATI Radeon QD rev 0 (both "radeon" and "ati" drivers) and NVidia GeForce2 GTS rev 163 ("nvidia driver) with NVidia GLX & kernel module v1.0-1251. Tested with and without xfs. Also tried adjusting the value of the default-resolutions parameter in /etc/fs/config. Tested with bitmap, type1 and TrueType fonts. The dpi setting in Mozilla doesn't seem to make a difference either.
For most cases, this is normal and expected behavior -- X only comes with two varieties of fonts -- 75dpi and 100dpi, and the choice between them is determined by the order of your fontpath. (/etc/X11/fs/config) Some programs may take resolution into account beyond this -- for instance, GTK+ version 2.0 ignores the resolution setting for fonts and picks the nearest bitmap font based on the pixel size of the fonts and the resolution -- but this is not common behavior currently. I don't know the details of the algorithm that mozilla uses for choosing font sizes. You might want to try switching to a scaleable font (such as URW Helvetica, insetad of Adobe Helvetica) and see if that makes it more responsive to resolution changes.
Indeed, as Owen has said, X comes with 75dpi and 100dpi fonts only, and scalable fonts. If the fonts do not look great, don't use the 100dpi/75dpi fonts, but instead use Type1 and truetype which looks great.