John Brown <johnbrown_...@yahoo.com> writes: > Can anyone say how emacs identifies a font that contains a glyph > that is not present in its current default font, and why it failed > to find DejaVu Sans Mono? It is not that important; I was just > testing emacs on a UTF-8 demo file.
Step 1: Check in the default font (that is why the character displays when the chosen default font contains that character). Step 2: Figure out which script the character belongs to, and build a shortlist of fonts which claim to have coverage of that script. Step 3: Discard any fonts that do not cover the characters listed in `script-representative-characters', as fonts often lie about which scripts they cover. Step 4: Look for the actual character in the shortlisted fonts. Things can go wrong at steps 2 and 3, either because of deficiencies in the fonts themselves, or in Windows reporting of scripts covered by the font. The situation on X is slightly better, as there is an API for querying whether a character is contained in a font without allocating resources for opening the font for drawing, so a more exact search can be done much more quickly.
