Re: [ft-devel] On contour directions and fill rules

[Behdad Esfahbod]

On 04/20/2012 12:31 AM, Werner LEMBERG wrote:
> 
>> It competes with freetype-gl really.  It's a GPU rasterizer.  The
>> main different with freetype-gl is that I don't do any sampling, so
>> the glyphs are truly infinitely zoomable.
> 
> Nice!  No time to look at it more closely, but I've recently skimmed
> over a paper which uses wavelet transformation to achieve something
> similar

Yes, I saw that exchange, but have not read it yet.


> (the paper was mentioned on this list a few days ago).  Maybe
> you are something into this direction also?

Not really, for this I just wanted to avoid signal processing by all means :).
 Essentially, it's a generic SDF rasterizer, like freetype-gl is, but instead
of using a 2D sample to represent the SDF, we use circular-arc splines.  So,
essentially, what GLyphy does is:

  - Convert glyph outlines to bunch of circular arcs,

  - Build a datastructure to make it fast finding which arc is closest given a
point,

  - Upload these all to the GPU, do the math in the fragment shader.

The devil is in the corner cases of course.  And in making it fast.

behdad

>     Werner
>