Werner LEMBERG <w...@gnu.org> writes: >>> Well, Metafont uses a third-order Bézier approximation to build up >>> circles (from four quarter circles). However, the Metafont book >>> says that the difference to a real circle is less than 0.06%, which >>> is thus imperceptible. >>> >>> The same holds for PostScript-based fonts. >> >> PostScript uses second-order Béziers, so it makes little sense to >> cite the mathematics of Metafont here. > > This is not correct. PostScript-derived fonts (Type1, CFF/CFF2 in > OpenType) *do* use third-order curves. I think you are mixing this up > with TrueType fonts, which indeed use second-order curves.
I was more talking about the curveto operator than fonts, but you are right either way. It was just Truetype that used only quadratic Béziers. Sort of embarrassing, since I distinctly remember putting explicit quartercircle approximations into the curved rectangles PostScript code. I did not find anything like that in the repository master though; it must have been an ephemeral part of the work for better rasterized PDF stems I did quite some time ago. -- David Kastrup
