[Pythoncard-users] Stopping an animation sequence.

[Rohit <ro...@gm...>]

Hi,
I have started using Pythoncard recently, so this may seem trivial. I
was going through the  samples which come with it and I found the
"gravity" sample, which animates a number of balls.
I also tried to do something similar to that, but just only for one
ball with one color. For this I used one button to start the
animation, another button to stop it and a canvas to draw the whole
sequence. In the animation sequence the program keeps on checking
whether a flag variable has been altered to stop the animation or not.
This flag variable was supposed to be altered by the stop animation
button, when a mouse click occured. But when I click the stop button
the animation keeps on running. I am including the code of my program.

[code]

import time,random
from PythonCard import model

class MyBackground(model.Background):

    def on_initialize(self, event):
        self.stopAnimation=3DFalse
        pass

    def on_startBtn_mouseClick(self,event):
        event.target.enabled=3DFalse
        self.stopAnimation=3DFalse
        xco=3D50.
        yco=3D0.
       =20
        xspeed=3Drandom.random()*60-30
        yspeed=3Drandom.random()*60-30
        leftedge=3D0
        rightedge,bottomedge=3Dself.components.canvas.size
        topedge=3D0
        gravity=3D2
        drag=3D0.98
        bounce=3D0.5
        radius=3D10
        self.components.canvas.fillColor=3D'red'
        prev=3D()
        while(not self.stopAnimation):
           =20
            self.components.canvas.drawCircle((xco,yco),radius)
            time.sleep(0.02)
            self.components.canvas.clear();
            self.components.canvas.refresh();
           =20
            xco=3Dxco+xspeed
            if(xco+radius>rightedge):
                xco=3Drightedge-radius
                xspeed=3D-xspeed*bounce
            if(xco-radius<leftedge):
                xco=3Dleftedge+radius
                xspeed=3D-xspeed*bounce
            yco=3Dyco+yspeed
            if(yco+radius>bottomedge):
                yco=3Dbottomedge-radius
                yspeed=3D-yspeed*bounce
            if(yco-radius<topedge):
                yco=3Dtopedge+radius
                yspeed=3Dyspeed*bounce
            if((int(xco),int(yco))=3D=3Dprev):
                break   =20
            yspeed=3Dyspeed*drag+gravity
            xspeed=3Dxspeed*drag
            prev=3D(int(xco),int(yco))
   =20
    def on_stopBtn_mouseClick(self,event):
        self.stopAnimation=3DTrue
        self.components.startBtn.enabled=3DTrue   =20
           =20
if __name__ =3D=3D '__main__':
    app =3D model.Application(MyBackground)
    app.MainLoop()


[/code]

Thanks for any help.

Rohit