Cubic Beziers are actually pretty good at making an S curve, in my opinion. Certainly, it's not uncommon in professional fonts to see a single Bezier traverse from a vertical tangent in the upper left corner to another vertical tangent in the lower right.
I agree Beziers are efficient, but I don't think this should seduce us into concluding they are natural.
If you draw the main slope of the S with, say, eight arcs, then the centers should describe a fairly continuous path in and of themselves. ... But if you don't do a good job visualizing the radii of curvature, and put the tool in novice hands, my guess is that you'll see bad curves.
That's a good point. But rather than having the user think about the circles, I wonder if they could use the abstraction of a digital spline and ducks (the non-mathematical meaning of spline). I suspect this is what Dr Karow had in mind when he came up with IKARUS' curve model.
it's probably not anywhere nearly as painful as you might think to work directly in the space of the Cornu parametersThat sounds interesting.
having an uneven baseline or x-height line is a pretty serious artifactSurely only subpixel placement can help with non-integral lineskips? But it seems to me that (at a cost of performance, i.e. glyph caching), FontFocus could be adapted to subpixel positioning? (In the vertical, to solve the baseline problem.)
The CoolType samples in your paper do not work. In my opinion the subpixel rendering on OS X and XP (and Adobe Reader 6) does a fine job; the screen dump can only work in exceedingly rare circumstances (1:1, digital LCD of correct triplet ordering, etc) and should be deleted from the paper as a misleading comparison.