GNOME Bugzilla – Bug 535041
Wrong positioning of letters
Last modified: 2008-08-12 17:45:43 UTC
Please describe the problem: Hi, I’m not sure if this is a pango or cairo bug, but I’m starting here. See the simple attached program that renders a string using cairo and pango. It is written in python, but the same behaviour was observed in an C package first (binary package sm), so it is a bug in the C libraries. It should print ":-)" in relatively large letters, but I get the output as in the attached image. This does not happen at all font sizes, but only for certan spans of sizes. This bug is relatively bad for users of screen-message (sm), because it makes it non-reliable. Thanks, Joachim (See http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=pangobug.py;att=1;bug=482329 and http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=pangobug.png;att=2;bug=482329 for the files, and http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=482329 for the currently non-existing discussion of this bug in the debian bugtracker) Steps to reproduce: Actual results: Expected results: Does this happen every time? Other information:
This is fixed in cairo master already. Please check.
Thanks, in this case I’ll just wait for the next release.
Hi, just wondering: Is this fix supposed to be in any release by now? The comments are from May, and it seems there were releases since then: (by looking at http://packages.qa.debian.org/p/pango1.0.html) Thanks, Joachim
Note that it is very surely related to kerning, and is a linear problem. It also appears not only for changing font sizes, but also for constang font sizes and changing scaling in the pango context matrix. It seems as if the scaling increases the kernel stronger than that it increases the font size: If I use screen message to only display "Ta", both letters are above each other. The more spaces I append to that, and thus the smaller the letters become, the more normal the kerning becomes, until it’s perfectly fine for „normal“ font sizes.
Sorry, it seems I have to re-open this bug. I just compiled and instlled the newest versions[1] of pango and cairo, but still: If I use sm to display "Ta", both letters are above each other. If you want to reproduce it, use this (fully auto-make-enabled) program: http://ftp.debian.org/debian/pool/main/s/screen-message/screen-message_0.13.orig.tar.gz Thanks, Joachim [1] pango1.0-1.21.4 and cairo-1.7.4
I'll look into this later, hopefully before 1.22. *** This bug has been marked as a duplicate of 341481 ***