void register_font_file_type(const char *ext, FONT *(*load)(const char *filename, RGB *pal, void *param));
FONT *load_my_font(const char *filename, RGB *pal, void *param)
{
...
}
The pal parameter can optionally be used to return a palette for the FONT.
The parameter param can be anything you like: you can use this to pass
information to your loading routine, such as for instance the font height,
the character range to load or the index number of a font in a datafile.
If you choose to write your own font loading code, your function should be
prepared to deal with a value of NULL for either of these parameters.