Re: [ft-devel] State of TrueType interpreter v38 and up?

[Nikolaus Waxweiler]

> There are a whole bunch of improvements for the auto-hinter not yet
> integrated, but this doesn't affect the TT engine.

Mhm, sounds like a job for me. I'll put it somewhere on my todo list :P

> There is a misunderstanding, see above.  `Native' ClearType doesn't do
> y-only hinting!  It's simply that advance width modifications are
> ignored in Windows at a later stage, namely in the rasterizer.

I'm confused. Is this "native ClearType" actually called "Natural 
ClearType" or "natural advance widths"? I guess that's something FT 
already does? What I meant to say is I want the part of ClearType that 
does Y-only hinting.

> ClearType consists of multiple parts. The first one is the
> interpretation of the hints, which is complete (more or less).

This, I guess? I don't fully understand the description of the 
interpreter versions. Does GETINFO == 39 (v2.0) and 40 (v2.1) bring 
anything to the table that would be relevant to FT?

A quick search didn't turn up any specifications except that one guide 
for how ClearType tries to be backwards compatible...

> The second one consists how the hinted outlines are converted to
> raster images. There are big differences between the MS engine and
> FreeType, which can't be `fixed' without completely redesigning
> FreeType.

Could you provide some specifics? Do you mean how the rasterizer handles 
anti-aliasing and subpixel-rendering?