Re: [ft] anti-aliasing question

[Tor Andersson]

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.

You can also use this freetype + opengl code I wrote a while back if you want
high quality smooth text with even spacing (like on Mac OS X), or experiment
with different freetype rendering options in an opengl environment:

http://ccxvii.net/repos/mio/font.c

-Tor