[HarfBuzz] Using HarfBuzz to get final glyphs

[Steve Mills]

We're looking at options for updating a 3rd party library (AGL from  
Alphamask, now dead, so we maintain it ourselves) we use for cross- 
platform rendering of vector objects, bitmaps, and text. Right now it  
does not allow for any of the nice OpenType features such as  
ligatures, contextual glyph substitution, etc. This is because it only  
knows how to do 1:1 character->glyph lookups, then caches those  
glyphs. So what I need to do is possibly rip out this caching scheme  
it uses and find something that will give me a final list of glyphs  
with all possible glyph substitutions in place (depending on which  
options the user wants to use, of course). We can then either use our  
existing method of rendering the glyphs (get the path with ATS), or  
possibly let some other system such as HarfBuzz create and cache each  
glyph's bitmap that we'll then blit to our drawing surface.

So, can HarfBuzz do this? We already use FreeType in our server  
products, but we need to handle the OpenType features on all platforms  
(Mac, Unix's, Solaris, Windoze, etc). It's very disappointing that  
they didn't extend FreeType to do this sort of thing. I've spent  
nearly an hour looking around the HarfBuzz site and being thoroughly  
confused by trying to learn how to use yet another wiki and yet  
another source repository, seeing lots of links that go nowhere  
helpful, and generally not finding a lot of documentation on how to  
use HarfBuzz, so I'm a bit burned out right now.

_________________________________________________________
Steve Mills                              Me: 952-401-6255
Senior Software Architect                         MultiAd
smills at multiad.com                       www.multi-ad.com