Re: Font support for utf8

On 2025-07-08, Lawrence D'Oliveiro wrote:

On Tue, 8 Jul 2025 10:20:49 +0100, Richard Harnden wrote:
>

Actually, I wanted to detect whether the font that happens to be in use
(which I can't control) has a particular glyph available.  I have no
problem choosing a suitable font for myself.
 
I thought that maybe there'd be some kind of ioctl call.

>
ioctl(2) calls are for device drivers, which are part of the kernel. What
you want is a call in the font APIs, which run entirely in userland.
>
On Linux systems, the two relevant subsystems would be Fontconfig and
FreeType. Fontconfig lets you query your system/user setup to find out
what fonts are available, and what their capabilities are. FreeType not
only takes care of low-level glyph rendering, it also lets you pry into
the innards of a particular font in more detail.

In this case, wouldn't a more appropriate route be introducing a
terminal escape sequence for this (or is there one already in use
somewhere?).

What I wonder about is speed, how would this be made efficient, a
library caching responses? Because UCS isn't small...

--
Nuno Silva