Re: A little polish of Thai shaper

[Owen Taylor <otaylor redhat com>]

Dov Grobgeld <dov Orbotech COM> writes:

> Speaking of vowels, I tested out Hebrew with vowels with the ClearlyU
> font, and they are placed in strange places. The problem with Hebrew
> wovels is that they may be divided into one of the following four
> categories:
> 
>    * centered below the base character (most vowels act this way)
>    * Right aligned (e.g. dot above SIN)
>    * Left aligned (e.g. dot above SHIN)
>    * in middle of character (e.g. dot within VAV)
> 
> What is not clear to me is where this kerning (meta) information is to 
> be stored

For BDF fonts, it's not. It's just a matter of convention for
where the accents are placed in the character cell for a particular
font.

We could use extra properties to store the information, as we do for
Indic ligatures, but that would require special fonts, wouldn't
work well

Better font systems do better - OpenType fonts have a powerful system
for accent placement.

> and what module is supposed to use this information to do the proper
> rendering.

We now have a hebrew shaper in Pango so it is supposed to do
this:

 pango/modules/hebrew/

Most likely, there is again a mismatch between the clearlyu fonts
and the expectations of this shaper.  

I'm not sure we actually _need_ a Hebrew shaper --- for anything
better than core X fonts, generic accent placement mechanisms
will probably work.

Regards,
                                        Owen