[NTG-context] Drawing oriented paths in MetaFun

[Giuseppe Bilotta]

Wednesday, November 16, 2005 Giuseppe Bilotta wrote:

> Does MetaFun provide some macro to draw oriented paths? I
> would like it to basically add a small arrow *in the middle*
> of the path? Such a macro

> draworiented somepath somespecs ;

> would have to act like

> drawarrow firsthalf(somepath) somespecs ;
> draw secondhalf(somepath) somespecs ;

> Is it available already, or should I roll my own?


Hm. I came up with

def draworiented expr c =
  path _c_ ; _c_ := c ;
  do_draworiented
enddef ;

def do_draworiented text t =
  draw _c_ t ;
  drawarrow subpath(0, length(_c_)/2) of _c_ ;
enddef;
 
which works, although I have to do

draworiented (reverse p1)

Is there an easy way to have it work with

draworiented reverse p1 ?

-- 
Giuseppe "Oblomov" Bilotta