From: William Henney <w.henney@as...>  20061029 16:21:40

On 10/29/06, William Henney <w.henney@...> wrote: > > Just a last one: > > I really need to implement MetaPostlike B=E9zier curves, "z0..z1" draw= s a > > B=E9zier curve from z0 to z1 without having to calculate the control > > points. Is there something similar in PyX and if not, where to find any > > reference ? > > As far as I know, there is nothing built in to PyX for doing this. It > would be great if there were! > > If you want to implement this yourself, then the wikipedia article > looks like a reasonable general introduction > (http://en.wikipedia.org/wiki/B%C3%A9zier_curve). The way metapost > does it seems to be reasonably well documented  see > http://www.tlhiv.org/MetaPost/documentation/, particularly > Metapost_Curves.pdf > I just found a better reference. This is John Hobby's original paper from 1985 on the algorithm that got used in metapost: ftp://db.stanford.edu/pub/cstr/reports/cs/tr/85/1047/CSTR851047.pdf You also might want to look at how this is done in asymptote (http://asymptote.sourceforge.net). They seem to have reimplemented Hobby's algorithm and also have generalized it to be invariant under 3D transformations. Cheers Will =20 Dr William Henney, Centro de Radioastronom=EDa y Astrof=EDsica, Universidad Nacional Aut=F3noma de M=E9xico, Campus Morelia 