[HarfBuzz] Selecting fonts for HarfBuzz

[Khaled Hosny]

On Thu, Jun 06, 2019 at 05:29:07AM +0300, Eli Zaretskii wrote:
> > From: Behdad Esfahbod <behdad at behdad.org>
> > Date: Wed, 5 Jun 2019 12:45:00 -0700
> > Cc: "harfbuzz at lists.freedesktop.org" <harfbuzz at lists.freedesktop.org>
> > 
> > HarfBuzz handles everything it understands.  It was designed, in fact, such that when combined with
> > FreeType or other external font funcs implementation, it even "handles" font formats it does not understand. 
> > Eg. HarfBuzz doesn't understand BDF, PCF, etc, but if you use hb-ft, you can use hb-ft for everything, and
> > BDF, PCF etc also magically work because HarfBuzz defers to FreeType for glyph access, and simply
> > "passes through" for the rest.  It was designed such that you can keep one shaping code path.
> 
> We don't currently use hb-ft on Windows.  But thanks, I think I
> understand.

You can achieve the same by implementing font functions for the font
formats HarfBuzz does not directly support, using e.g. GDI API to access
glyph info in these fonts (see hb_font_funcs_set_* functions).

Regards,
Khaled