> The 4-fold speed difference is not an optimization, it is a liability which should be taken explicitly. Some overlaps at single points are not that noticeable. Only long runs along the axes are bad. So I disagree with default oversampling even for variation fonts.
Let me explain that not all overlaps are bad - see attached "X". The middle is acceptable because the contours intersect at single points rather than edges. Therefore the artifacts are isolated at single pixels and barely noticeable. The situation at the top is horrible because the stems extend through the serif bars up to the edge. Multiple adjacent pixels are improperly dark. If only the font designers end the stems in the middle of the serif bars, nobody would even notice anything. The font designers should be aware of this and decide if FT_OUTLINE_OVERLAP is truly necessary.
