Re: [Q] What happened with subpixel rendering in art backend?

[Johannes Fortmann]

Am 08.10.2005 um 15:11 schrieb Christopher Armstrong:

> Having read the WWN (wine weekly news) lately, I think I can answer  
> your
> question. Subpixel rendering in freetype2 uses algorithms under patent
> (ironically, their held by Apple) and freetype2 is usually compiled
> without them, to avoid infringement. If you live in a country that  
> does
> not recognise software patents, you may be able to recompile freetype2
> for subpixel support.
>
> Apparently the wine project is having similar issues, and is  
> looking for
> a solution as well.
>
> This is coupled from what I remember reading on WWN; you may want to
> check out freetype2's mailing list for more details. I'd say this is
> what happened to subpixel rendering.
>
> Cheers

I don't think that is the issue here. freetype2 basically has two modes:
-with TT_CONFIG_OPTION_BYTECODE_INTERPRETER defined in ftoption.h,
 the Apple-patented bytecode interpreter is used. This means type  
hinting is done
 according to the hinting information in the font.
- without that option set, there are no hints. That doesn't keep  
freetype from anti-aliasing,
though: it just has to guess what the hinting would be (this is done  
by the so-called
"auto-hinter"). In some cases, this option can even hint much better;  
there are
some fonts with corrupt hinting information floating around, which  
look horrible
with the interpreter option.
Anyway, the worst that can happen if the bytecode hinter is disabled  
is that the
glyphs look a bit worse at small sizes (<10 pt.). The _availability_  
of antialiasing
should not be affected, only the quality.

BTW, the really ironic part is not that Apple holds the patents  
(after all, it would be
them or MS), but the fact that Mac OS X ships freetype2 with the  
interpreter off.

HTH,
J. Fortmann