On Thu, 2009-03-26 at 09:22 -0500, Jud Craft wrote:
No idea. Probably something to ask the freetype people, or whoever
implements the rest of the subpixel filters.
There is someone who implemented such an idea by considering the red
and blue subpixels as dependently linked, since together red and blue
have an approximate luminance as green. It was called the SubRGB
algorithm, and there was a page with source, a library, and examples
-- but I can't find it in google. I don't believe it was ever used in
any font-rendering library, but it was suggested as a possible
non-patent infringing replacement.
Note that a FreeType developer is not so convinced that SubLCD is
completely in the clear:
http://david.freetype.org/cleartype-patents.html