Re: [ft-devel] regarding freetype 2 cubic curve flattening

[Alexei Podtelezhnikov]

> On 30/10/2011 08:25, Vivek Rathod wrote:
> according to Hain's paper
> dmax = (s/L) * dnorm ;  here s  is not normalized. dmax is the tolerance for
> flatness and dnorm is the normalized flatness of the curve.
>
> so s_limit = (dmax / dnorm) * L ; by putting dnorm = 0.75 we get the
> permissible height of the control point for the curve not to be split.
>
> so should we  not be comparing s= abs(dy * dxi - dx * dyi) with s_limit *
> L    instead of s and s_limit  ( because s is perpendicular distance of
> control point multiplied by L) ?


It is actually not just cross-product but

s = abs(dx * dxi - dx * dyi)  / L

otherwise the dimensionality is wrong.
Some Hain's equations just need to be creatively modified to avoid divisions
in the code.