[HarfBuzz] Inter-glyph spacing

[Simon Cozens]

On 13/09/2014 17:05, Simon Cozens wrote:
> Deeper and deeper.

The problem is, of course, that I am an idiot. Nothing to do with scaling or 
Graphite or Harfbuzz.

This line in my code while configuring fontconfig

       if (f->slant)
         FcPatternAddInteger(p, FC_SLANT, f->slant);

meant that the FC_SLANT pattern was not being added in cases where f->slant is 
zero, which is unfortunately FC_SLANT_ROMAN. Doubly unfortunately, fontconfig 
can sometimes choose an italic font by default if you don't explicitly specify 
a slant. So I was rendering a Roman font with spacing that Harfbuzz correctly 
computed for an italic font. Hence the strange spacing problems.

Sorry! Harfbuzz works perfectly now I've removed that.

For what it's worth, I've written up what I've learnt at
http://www.simon-cozens.org/content/duffers-guide-fontconfig-and-harfbuzz