Hey everybody-
I seem to be consistantly running into troubles with Freetype and Greenville. I suspect the problem stems from Freetype trying to render the glyph with too many shades of grey, and I *SERIOUSLY NEED* somebody to fix it.
Here is a more technical view of the situation, and the problem:
The TrueType hinting system allows each pixel to be subdivided into sub-units. There are 81 subunits per pixel, in a 9x9 grid, with the center being the origin point. So, it looks something like this:
87654321012345678 7XXXXXXXXXXXXXXXX 6XXXXXXXXXXXXXXXX 5XXXXXXXXXXXXXXXX 4XXXXXXXXXXXXXXXX 3XXXXXXXXXXXXXXXX 2XXXXXXXXXXXXXXXX 1XXXXXXXXXXXXXXXX 0XXXXXXXXXXXXXXXX 1XXXXXXXXXXXXXXXX 2XXXXXXXXXXXXXXXX 3XXXXXXXXXXXXXXXX 4XXXXXXXXXXXXXXXX 5XXXXXXXXXXXXXXXX 6XXXXXXXXXXXXXXXX 7XXXXXXXXXXXXXXXX 8XXXXXXXXXXXXXXXX
That represents the total number of subunits, and their coordinate placements within 1 pixel.
The windows rasterizer determines the 'shade' the pixel will get, based on % of coverage this pixel gets from the outline, as does freetype. The problem shows up, because The windows type rasterizer only renders 16 shades, including Black and White, while the Freetype one renders 256 shades.
There are only 81 units, however.
What does this mean? It means that under freetype as it currently stands, if even *ONE* pixel subunit is covered by an outline, it will render as a shade of grey--- While the exact same pixel, with the windows rasterizer, will render as 'white' instead.
This is because "white" is 1/256th coverage, and there are only 81 subunits-- Essentially meaning that in order to get 'white' out of freetype, the pixel cannot be touched *AT ALL* by the glyph outline.
On the windows rasterizer, there are only 16 shades of grey, so up to 1/16th of the area can be covered, and still rendered as 'white'-- or 5 subunits covered.
This is why the windows rasterizer produces crisper images than Freetype.
I don't know how to fix this behavior in Freetype, and *SERIOUSLY* need said behavior changed, As soon as possible.
Thank you.
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