Misplaced Unicode combining characters

[Keith Winstein]

Binary package hint: ttf-dejavu

DejaVu Sans Mono Book produces bizarre behavior with some combining characters. See http://web.mit.edu/keithw/www/badcombine3.html

In gedit or gnome-terminal with DejaVu Sans Mono, the first circumflex is correctly positioned over the second "x" in the row. But in the second line, the circumflex is improperly one character to the right of where it should be.

In the third line, the second "o" should have a circumflex, a minus sign below, and a slash through it. The first two combining characters are rendered correctly, but as for the slash, instead of striking the second "o" it either gets its own space (in gedit) or strikes the next letter (in gnome-terminal).

In the fourth line, the second "-" should have all three combining characters. Instead the three diacritics either each get their own space (in gedit) or are applied to later characters in the same line (in gnome-terminal).

Similar bugs affect most monospace fonts (see, e.g., https://bugs.launchpad.net/ubuntu/+source/ttf-liberation/+bug/299158), with different wrinkles in each case. I also see buggy behavior with Andale Mono, Courier New provided by the ttf-mscorefonts-installer, package, etc., so there may be a more general bug with TrueType rendering.

This is on Ubuntu 10.10, ttf-dejavu 2.31-1.