From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040403 Firefox/0.8 Description of problem: When running a program inside of an XTerm that returns a lot of output (for instance, running 'make'), garbage characters collect on the screen, most often at the bottom, but sometimes elsewhere. These characters look like underscores, or possibly dashes. The problem can be cleared up by running xrefresh. This only appears to happen when using TrueType fonts. This happens under any windowmanager. Given a long time without an xrefresh, these characters can fill up a significant section of the screen. Version-Release number of selected component (if applicable): xterm-179-6.EL How reproducible: Always Steps to Reproduce: 1. Open an XTerm that is configured via a .Xresources or .Xdefaults file to use a TrueType font. Configuration via runtime parameters should also work. 2. Run a program that returns multiple lines, whole screens even, of output. Compiling a program is a good example. Actual Results: The underscore characters appeared at the bottom of the screen. Expected Results: The underscore characters should appear at the bottom of the screen, sometimes they are sparsely spread of other areas of the screen.
Screw up in 'Expectes Results:', should read: "Underscore characters do not appear at the bottom of the screen."
That sounds like what I'd call pixel-trash. xterm tries to check for characters that go outside their bounding boxes, but some fonts have incorrect metrics (and of course xterm may not do this check perfectly). A specific font and size would help to reproduce the problem and see whether I can improve this.
So far I've found that it happened with Bitstream Vera Sans Mono at every size that I've tried, without fail. The only other monospace fonts I have are Andale Mono, Courier & Courier New, and the default 'Monospace.' All of those don't appear to cause this problem.
The default 'Monospace' as it turns out is Luxi Mono, if that helps.
Does this occur in Fedora Core 3 as well?
I had a second report (user on FreeBSD 5.3) citing the same font, X11R6.7. I don't see it with this font on Debian/testing though. (I would test with Fedora, but its mouse driver doesn't work for my machine). But I do have the FreeBSD working, will look there when I'm testing it.
Since this bugzilla report was filed, there have been several major updates to xterm which may resolve this issue. Users who have experienced this problem are encouraged to upgrade to the latest version of Fedora Core, which can be obtained from: http://fedora.redhat.com/download If this issue turns out to still be reproduceable in the latest version of Fedora Core, please file a bug report in the X.Org bugzilla located at http://bugs.freedesktop.org in the "xorg" component. Once you've filed your bug report to X.Org, if you paste the new bug URL here, Red Hat will continue to track the issue in the centralized X.Org bug tracker, and will review any bug fixes that become available for consideration in future updates. Setting status to "CURRENTRELEASE".