Re: [ft-devel] Detect all available characters in a font?

[Werner LEMBERG]

> Is there any way to detect all the available characters in a loaded
> font?

It depends on how you define `character'.  If you mean `I have an
input character code, and I want to know whether the font has a glyph
for it', then the answer is yes.

> It would be convenient if I had some way to do this:
>
> for (i=0; i<FT_Font_CountChars(font); i++ )
> {
>     c = FT_Font_GetChar( i );
>     //Proceed to load character 'c'...
> }

Well, just use

      {
        FT_ULong  charcode;
        FT_UInt   gindex;


        charcode = FT_Get_First_Char( face, &gindex );
        while ( gindex != 0 )
        {
          ... do something with (charcode,gindex) pair ...

          charcode = FT_Get_Next_Char( face, charcode, &gindex );
        }
      }

to iterate over all characters contained in a given cmap.  This is the
example from the documentation of FT_Get_First_Char.

Note, however, that this is a very naive approach which certainly
fails for non-latin scripts.  For example, to properly render
Devanagari scripts, it's not sufficient to use the above code since
there are 112 glyphs defined in the block U+0900 - U+097F but you need
a few hundred glyphs to be accessed via input character code
reordering and heavy use of ligatures.

You can avoid such hassles if you try one of the various high-level
libraries like Qt, Pango, ICU, or, to a certain extent, libotf.


    Werner