[metapost] Re: new is_clockwise routine

[Taco Hoekwater]

Werner LEMBERG wrote:
>>Finding the direction at which a curve turns at any given
>>point is easy: just find the sign of the cross product [...]
> 
> 
> In my macros I use the cross product to check for grazing intersection
> only.
> 
> 
>>In general, to find the clockwiseness of a single Bézier
>>cubics it suffices to check [...]
> 
> Far too complicated and slow to be implemented as macros IMHO.

Put it looks like precisely the right way to fix the turningnumber
primitive. Giuseppe, any chance of you writing some code for this?

Taco