[cairo] UserFontFace vs FtFontFace management (cairomm)

[Ian Britten]

Jonathon Jongsma wrote:

>> [ NB - I'm pretty sure this is cairomm-specific ... ]

>> Are users supposed to be able to create+manage UserFontFace
>> objects the same way as FtFontFace objects?  If yes, then I'm
>> wondering about a crash I'm seeing...
>> [ If no, then the docs should maybe clarify the difference ]

>> (*) The problem, as reported by Valgrind, seems to be that
>> Cairo::UserFontFace::render_glyph_cb() (fontface.cc:287) is
>> accessing something that was deleted in
>> Cairo::UserFontFace::~UserFontFace()() (fontface.cc:330).
>> [ I can provide full traces, if necessary ]

> It's quite possible that you've hit a bug since this stuff was only 
> implemented in cairomm recently (and I've held off on releasing a stable 
> 1.8.0 of cairomm precisely because this stuff hasn't been well-tested 
> yet).  In fact, you're very likely the first person to have tried to use 
> it.  I will look into it.

Hmmm...  If that's the case, is the interface still open to
discussion/change?  :)

As I've start trying to use it, I got wondering if it wouldn't
make more sense (and be more C++-like) for UserFontFace to be
an abstract class, with a pure-virtual 'render()' method, and
virtual 'init()', etc, methods?
I'm just working through setting up the function pointers, and
trying to decide where to store my client-data (requiring a
separate struct, etc), and got thinking that if I could simply
derive from UserFontFace and carry my extra information in my
own derived implementation, it would probably simply things.

Anyways, just some initial thoughts...
Ian