[HarfBuzz] hb-view

[Behdad Esfahbod]

Hello everyone,

As promised, I pushed out the initial code for a hb-view cmdline tool.
There's a thousand things missing right now, but it's a good start.

In particular, in the near future I want to do:

  - Somehow be able to set script and direction.  For script, I'm currently
thinking about making harfbuzz internally scan for the first non-Common script
in the string if the buffer script is set to HB_SCRIPT_COMMON.  That should
work fairly well for simple cases.  For direction, it's harder.  HarfBuzz
internally knows about native horizontal direction of scripts, so I like to be
able to use that.  However, that would require adding either HB_DIRECTION_NONE
or HB_DIRECTION_WEAK_LTR/RTL/....  I can't make up my mind about this.
Suggestions?

An alternative would be to 1) add a full-fledged script iterator to HarfBuzz,
2) use FriBidi to do real bidi.  That would make the tool much more usable at
the cost of requiring FriBidi.

  - Add support for PS/PDF/SVG output.

  - Port to glib option parsing.  Hopefully people don't mind the glib use, right?


Also a design question: should the tool require all the ingredients (freetype,
cairo, glib, fribidi?) and do a perfect job, or if some ingredients are
missing it should just use fallbacks, which would result in inferior output?
For example, if glib is missing, you wouldn't get the Unicode funcs, if
fribidi missing, no bidi.  I'm leaning towards always-correct output.  Makes
the tool much easier to use as a debugging tool.

Later on, perhaps add json/xml output too.  Or would that be better done in a
separate tool?

Any other comments?

Cheers,
behdad