Re: [ft-devel] Rendering artifacts

[malc]

On Mon, 26 Jul 2010, Werner LEMBERG wrote:

> 
> > That said i first noticed the invisibility problem while using
> > seamonkey/firefox/whatever which all rely on fontconfig.
> 
> Hmm.  You should file a bug report for fontconfig.
> 
> > FWIW i tried using Liberation Serif under Vista and it does AA the
> > glyphs, however the leg of k is perfectly visible.
> 
> Vista uses ClearType by default, not yet supported by FreeType (see
> below)...
> 
> > And while at it, i'd like to point at another interesting case,
> > namely Linux Biolinum where when using full native hinter and rgb AA
> > the color fringing is just insane (again under Vista there's no
> > fringing)
> 
> I suspect this is the same issue (this is, missing ClearType support).

Will try to opt-out of cleartype in favour of "that other" AA option
next time i boot the box which has vista on it.

> 
> > And a final remark, i'm using decent CRT monitor and in general do
> > not use AA at all, it's just that a friend was preaching the
> > ClearType to me for a while and i decided to try it out, and indeed
> > i was pleasantly surprised (after trying different AA options here
> > on linux and osx, i'd say that the thing doesn't look all that worse
> > than bitmap/non-antialiased-but-well-hinted fonts)
> 
> ClearType consists of two components:
> 
>   (a) Rasterizing a font with a greatly enlarged horizontal
>       resolution, using some nasty tricks (with help of a database of
>       known `problematic' fonts) to make that work for old legacy
>       fonts.  In particular, a bunch of instructions are disabled,
>       mainly for handling diagonal strokes.  We don't have this in
>       FreeType yet.

I see, there was also a patch [1] posted here a while ago, i forgot
to test Liberation Serif with this one.

>   (b) Using the result from (a) and applying a special (patented)
>       filter to achieve a good color balance for subpixel rendering.
> 
> (a) gives improvements on a CRT also.
> 

Yes it does.

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