Re: [Render] OpenType support in Pango

[Owen Taylor <otaylor redhat com>]

Keith Packard <keithp keithp com> writes:

> > So, I needed both the charmap table set and the ability to
> > render using raw glyph codes. What I did was load up the
> > font using Xft unencoded by the "glyphs-unencoded" encoding,
> > and then called FT_Set_Charmap myself. 
> 
> That seems fine; you want Xft to use no charmap which this will do.

My only (somewhat hypothetical) concern with this method is there
might be two fonts matched by a pattern, one of which has a 
iso10646 charmap, one which doesn't. When I load the font with
"glyph-unencoded", if I get the font without the iso10646 
charmap, then its hard to fix things up.
 
> However, realize that I just fixed Xft to share faces and fonts so that 
> multiple fonts referencing the same face will share the underlying 
> FreeType data structures; if you open more than one font, you'll need to 
> be careful to set the encoding and sizes with the (soon to be exported)
> 
> 	Bool
> 	XftFreeTypeSetFace (FT_Face face, FT_F26Dot6 size, int charmap)
> 
> interface instead.  The 'charmap' is the index into the list of supported 
> encodings for that face (face->charmaps[charmap]).  You can search that 
> list to make sure an iso10646 encoding exists for your application.  This 
> is independent of the charmap used by a particular font.

Hmmm. Does this mean that I can't assume that the FT_Face for a
particular XftFont will stay the same over time? (I assume the reason
for this call is so you can unshare as necessary.)

Regards,
                                        Owen