Re: [ft] anti-aliasing question

[Dave Calkins]

On 2/5/2010 4:17 PM, Dave Calkins wrote:
> > > > You get less blurrier output if you don't do subpixel position of
> > > > glyphs.
> > > How do I control whether or not subpixel positioning of the glyphs 
> > > occurs?
> > What is the translation component of the transform? If it is non-zero 
> > then the
> > grid fitting won't help against blurriness (since the pixel-aligned
> > outline will then
> > be shifted to between pixels, making the rendering all blurry).
> >
> > -Tor
>
> In tracing into the call to FT_Render_Glyph, it eventually goes into 
> ft_smooth_render_generic.
>
> When it gets here origin is NULL and so FT_Outline_Translate is not 
> called.  So I think the answer to your question is that no translation 
> is occurring.
>
> FreeTypeGL is rendering a single glyph using FT_Render_Glyph and then 
> using the resultant gray-scale bitmap to create a 2D GL texture.
>
> I noticed while tracing through ft_smooth_render_generic that 
> FT_CONFIG_OPTION_SUBPIXEL_RENDERING is not defined.

maybe I spoke too soon.  Tracing further shows the below.  Here, x_shift 
== 64 and y_shift == 0.

    /* translate outline to render it into the bitmap */
    FT_Outline_Translate( outline, -x_shift, -y_shift );