Re: [Silgraphite-devel] Re: Pango and SILGraphite was Re: Possible Pango 1.4 ideas

[Owen Taylor <otaylor redhat com>]

Tony Graham <Tony Graham Sun COM> writes:

> Owen Taylor wrote at 27 Jan 2003 17:48:20 -0500:
> ...
>  > Glyph codes are actually opaque integers in the Pango system; there
>  > is no exported relationship at the application level between a Glyph
>  > code and anything externally meaningful, though it happens that
>  > for the Xft and FT2 backends, the Pango glyph code matches the 
>  > TrueType glyph index.
> 
> Is there always a match or is it always a match only for TrueType
> fonts?
> 
> >From the documentation for FT_Get_Char_Index:
> 
>    FreeType computes its own glyph indices which are not necessarily
>    the same as used in the font in case the font is based on glyph
>    indices. Reason for this behaviour is to assure that index 0 is
>    never used, representing the missing glyph.

Well, most precisely, it matches the FreeType glyph index.  The
FreeType glyph index needs to match the TrueType index though, for
TrueType and OpenType fonts since those indices are referred to in the
OpenType tables.

Regards,
                                        Owen