Comment 21 for bug 299158

This is a problem even at the desktop level. With the gnome desktop font set to the default 'Ubuntu 11' if I use an app (gImageReader in my case, see also https://github.com/manisandro/gImageReader/issues/613) to write certain decomposed characters (e.g. \u0069\u0300), they are not properly combined on the screen. This is a bad user experience. I've switched to 'DejaVu Sans 11' as a workaround, as it seems to handle everything correctly so far. However, the related DejaVu Sans Mono Book still messes this up (e.g. in gnome-terminal and gedit), but on different combined characters. So for monospace needs I've found FreeMono to cover the most ground (pkg: fonts-freefont-ttf). Try this, while switching between the default gnome-terminal font (Ubuntu Mono?) and DejaVu Sans Mono Book:

$ echo -e '\u0069\u0300\u0020\u0254\u0327'
ì ɔ̧

The ì renders correctly while the open o + cedilla doesn't, both here and with the terminal font set to DejaVu Sans Mono Book, but if you switch to the default font in the terminal the open o + cedilla renders correctly while the ì renders with both the dot and the grave accent on top of each other, rather than the dot disappearing like it should.

I would guess that the related font definitions (Ubuntu Regular/Mono, DejaVu Sans Mono, possibly others) are simply incomplete when it comes to these less common character combinations.

font-manager has been very helpful for side-by-side comparisons of sample text in multiple fonts.