Re: [ft] anti-aliasing question

[Dave Calkins]

On 1/28/2010 12:51 PM, Tor Andersson wrote:
> On Tue, Jan 26, 2010 at 5:14 PM, Dave Calkins<address@hidden>  wrote:
>    
> > When comparing FreeType text rendering (in OpenGL via FreeTypeGL) with
> > Windows GDI text rendering, it appears that FreeType is applying "more
> > aggressive" anti-aliasing effects.
> >
> > The GDI text is anti-aliased, just not "as much".  The FreeType text looks
> > much smoother.
> >
> > I'm curious, are there parameters to fine-tune "how much" anti-aliasing is
> > applied?
> >      
> I believe you are looking for how much hinting, also known as grid fitting,
> is applied rather than anti aliasing. Windows font rendering deforms the
> font outlines very aggressively to align to the pixel grid, resulting in very
> few gray pixels when rendered.
>
> You'll have to look at the FreeTypeGL source to see what options it
> passes to freetype for rendering. If you want to get results close to what
> Windows does by default you'll need to use the bytecode interpreter hinting.
>
>    

I checked the FreeTypeGL source and it looks like its passing in the 
below values.

    For FT_Load_Glyph, FT_LOAD_NO_HINTING | FT_LOAD_NO_BITMAP

    For FT_Render_Glyph, FT_RENDER_MODE_NORMAL

Experimenting with these hasn't seemed to have any effect on the amount 
of smoothing (whether anti-aliasing or a result of hinting).

Basically I guess I'd like fewer gray pixels :)  Not sure how to get 
that result.