Bugzilla – Bug 215602
IPA fonts are rendered poorly
Last modified: 2006-11-24 14:50:15 UTC
IPA fonts are not rendered well with autohinter, and the fonts do not have enough bitmaps. Here is a patch to fix the problem: --- suse-hinting.conf.bak 2006-10-23 23:54:32.000000000 +0900 +++ suse-hinting.conf 2006-10-27 15:16:47.000000000 +0900 @@ -163,5 +163,24 @@ </edit> </match> +<!-- +IPA fonts are not rendered well with autohinter, +and the fonts do not have enough bitmaps. +--> + <match target="font"> + <test name="family"> + <string>IPAMincho</string> + <string>IPAGothic</string> + <string>IPAPMincho</string> + <string>IPAPGothic</string> + <string>IPAUIGothic</string> + </test> + <edit name="autohint"> + <bool>false</bool> + </edit> + <edit name="embeddedbitmap"> + <bool>false</bool> + </edit> + </match> </fontconfig>
Created attachment 102791 [details] a patch to fix
Created attachment 102823 [details] to-autohint-or-not-to-autohint.png Comparison of rendering with and without autohinter. Fonts displayed with xfd -fa "IPAMincho:pixelsize=15" xfd -fa "MS Mincho:pixelsize=15" xfd -fa "Sazanami Mincho:pixelsize=15" The top row of the screen shot shows the fonts without autohinting, the bottom row the same fonts with autohinting.
When looking at the screen shot attached in comment #2, I believe that all three fonts I used for testing look better with the autohinter than without.
This is even more obvious if one makes a similar screen shot for the "Gothic" fonts instead of the "Mincho" fonts because the autohinter works even better for simpler font designes like "Gothic".
Created attachment 102848 [details] with- / without- autohinter All numerical characters should have same width, but "8" is wider than "0" with authohinter. "8" also looks very bad with autohinter: it's not symmetrical.
I recommend to use a good Latin font for digits and the latin alphabet. The Latin part of most CJK fonts is not very good.
I can reproduce your screen shot in comment #5 here as well.
The problem that the Latin glyphs are not monospace (as they should be) when the autohinter is used happense with IPAGothic, Sazanami Gothic, and Meiryo. But it doesn't happen with MS Gothic.
Created attachment 102858 [details] hiragana.png (In reply to comment #6) > I recommend to use a good Latin font for digits and the latin alphabet. > The Latin part of most CJK fonts is not very good. Okay, compare with Japanese Hiragana. ;-) The baseline of the characters are not stable with autohinter. For example, "?" (NI, 2nd character of last line) is rendered upper one pixel than other characters with autohinter.
On the other hand, the に rendered with the autohinter is "sharper" (has less gray) because it is better aligned to the pixel grid. By aligning glyphs to the pixelgrid, one can reduce the blurredness but this comes with the cost of a slightly distorted positioning. For that reason, currently OpenOffice completely ignores the system settings concerning hinting and *always* forces no hinting at all. This has the advantage that the positioning of all glyphs is correct, especially line lengths are correct (no such effects as in the screen shot in comment #5). But the obvious disadvantage is that most glyphs are a lot more blurred. People comlain about that as well. No matter which of the the settings one chooses, somebody will complain.
I agree with you that someone prefer character shape and geometry than sharpness, others prefer sharpness than character shape and geometry. (I'm the former and you are the latter I think.) Since settings in "suse-hinting.conf" can be overridden by ~/.fonts.conf, the focus is which is more suitable as default. I think autohinter should be disabled by default for IPA fonts as long as it has an obvious disadvantage as I noted in commen #5.
New fonts-config submitted to STABLE: ------------------------------------------------------------------- Wed Nov 15 19:20:16 CET 2006 - mfabian@suse.de - Bugzilla #215602: don't use the embedded bitmaps in the IPA fonts because they are only available in 12, 14, and 16 pixels. - Bugzilla #215602: Don't use the autohinter for fonts where it it distorts the metrics so badly that even the digits which should be monospaced are not monospaced at all anymore. - Don't use the autohinter for good quality TrueType fonts. ------------------------------------------------------------------- You can download the new package for testing here: http://software.opensuse.org/download/M17N/SUSE_Factory/noarch/fonts-config-20061025-8.1.noarch.rpm /usr/sbin/fonts-config generates /etc/fonts/suse-hinting.conf and /etc/fonts/suse-bitmaps.conf which contain the new setup. The autohinter is not only switched off for the IPA fonts but for all TrueType fonts because - high quality TrueType fonts like Déjà Vu look much better when the byte code interpreter is used instead of the autohinter. - among the fonts which look better (i.e. sharper) when using the autohintern, *many* have severe problems with the distortion of the metrics. I only switched the autohinter on again for a rather small list of fonts where it really seems to help *and* where I could not find serious metrics distortion. Closing this bug as FIXED.
Fixed on RC1. Thanks!