[Visualpython-users] Problem with dragging objects

[Reinhard O. <old...@ma...>]

  Dear All!
VPython is really agreat library that I love very much. But now I tried 
to make points dragable in a seemingly very simple way:

from visual import *

def Vmainloop():

     while 1:

         if scene.mouse.events:

             ev=scene.mouse.getevent()

             if ev.drag: VdragEvent(scene.mouse.pos,scene.mouse.pick)

def VdragEvent(pos,obj): obj.pos=pos

def makePoint(pos): return sphere(pos=pos,radius=0.2,color=color.red)

[A,B,C]=[makePoint((-3,1,1)),makePoint((3,1,1)),makePoint((0,5,1))]

scene.autoscale=0

Vmainloop()


However, this does not work. The points are draggable, but only a very 
small distance. After that, no further events are triggered. Obviously, 
after dragging it a bit, it is no longer picked. But this is strange 
because the position has been updated.

Does anybody have a hint on this?

Reinhard Oldenburg

-- 
Prof. Dr. Reinhard Oldenburg
Goethe-Universität Frankfurt
Institut für Didaktik der Mathematik und Informatik
Senckenberganlage 9
D-60325 Frankfurt/Main
Telefon  +49 (0)69 798 23770
Telefax  +49 (0)69 798 22553
E-Mail   old...@ma...
WWW      www.math.uni-frankfurt.de/~oldenbur