Determining whether a glyph is available in Tkinter

[Terry Reedy]

On 12/16/2013 12:32 PM, wmcbrine at gmail.com wrote:
> I have a Tkinter app that can optionally label some buttons with
> certain Unicode glyphs that aren't always available (depending on the
> OS, etc.).

It depends on the font in use. The best scenario would be to always use 
the same unicode font. Idle, built on tkinter, has a configuration 
dialog that gets a list of available fonts and sets the one the user 
selects. I use Lucida Sans Unicode. It is not very pretty, but it seems 
to cover much the BMP. AFAIK, it should be available on all Windows from 
XP on. I do not know what comes with *nix and mac, but from reading
https://en.wikipedia.org/wiki/Unicode_font#List_of_Unicode_fonts
there seem to be TrueType fonts that you could install with your 
software: FreeSerif (etc), GNU Unifont, (both GPL), BitstreamCyber (free 
for non-commercial use). The font table linked above is followed by 
table indicating something about coverage. Unifont is the champ.

 > When they aren't available, Tkinter renders them as
> "\uNNNN". What I'd like to do is check whether the glyphs are
> available, and fall back to my own alternate text for the button if
> not. Can I do this?

Don't know. See the 'Utility software' section of the page above.

> I'd also like to do the same in pygtk.

No idea.

-- 
Terry Jan Reedy