Re: Thai Shapper without needed extra glyphs for vowel/tonemark at different heights

[Owen Taylor <otaylor redhat com>]

Chookij Vanatham <chookij vanatham eng sun com> writes:

> Hi Robert,
> 
> 
> ]From: Robert Brady <robert suse co uk>
> ]Subject: Re: Industry Thai Cell-Clustering Rules
> ] 
> ] They can also do y adjustments on glyphs.  It would be quite easy I guess
> ] to make a Thai renderer that could do nicely positioned vowels without
> ] needed extra glyphs for vowel-at-different-heights.
> ] 
> 
> I just understand what you were talking about this because of
> the data structure of PangoGlyphGeometry.
> 
> 
> struct PangoGlyphGeometry
>  {
>    PangoGlyphUnit width;
>    PangoGlyphUnit x_offset;  
>    PangoGlyphUnit y_offset;
>  };
>  
> Then, may be, we don't need to have various kinds of Thai WIN/MAC font layout
> but the font might still need to have the special glyphs for U+0E0D and U+0E10.
> Those special glyphs won't have the bottom piece which is below the main body
> of these two consonances. Then, it should be ok. Right ?

If the number of extra glyphs is small, I think simply using the 
WIN/MAC font layout is easier. The trouble with using x_offset/y_offset
is that the offsets you need depend on the exact font layout and
size.

Regards,
                                        Owen