Re: [ft-devel] Autohinter: stem darkening, first rough prototype

[Nikolaus Waxweiler]

> Normal Type1 fonts work like that.  CFF, on the other hand, can have
> different stdVW values for subfonts – and large, high-quality CJK
> fonts like HiraKakuPro contain *a lot* of subfonts:

> CID-keyed (and other?) CFF fonts have multiple FontDict's (aka FD).

> multiple private DICTs (subfonts) and therefore multiple Std?W values
> per font for CID fonts

Alright, alright, I stand corrected ;)

Doing it per script actually made things easier. Everyone who cares 
please have a look at 
https://github.com/madig/freetype2/tree/stem-darkening-autohinter.

The darkening amount is now lazily computed per size AND per standard 
width of the glyph's script. This means that each time a glyph is loaded 
by the autohinter and its' standard width as determined by the script 
analyzer changed compared to the glyph before it, the darkening is 
recomputed.

And I only had to extend the writing system class by
typedef void
(*AF_WritingSystem_GetStdWidthsFunc)( AF_StyleMetrics  metrics,
                                      FT_Pos*          stdHW,
                                      FT_Pos*          stdVW );
:)

Okay, what remains? More comments maybe, af_loader_compute_darkening() 
cleanup and testing.

I had a quick look at various fonts and darkening seemed fine, but CJK 
glyphs (SourceHanSansCN-Regular.otf) appeared a bit thin compared to the 
CFF engine. Will investigate... some other time.