What I do is rounding the glyph position to 1/4 of pixels, in my tests it has not much visual impact. That still mean in the worst case the glyph cache could co

What I do is rounding the glyph position to 1/4 of pixels, in my tests it has not much visual impact. That still mean in the worst case the glyph cache could contains 16x the same glyph, and that's before hinting enters the equation.