# Ported from Brent B. Welch's book Pratical Progamming in Tcl and Tk, 2nd Edition.
# Example 31-8 A canvas stroke drawing example.

import types, string, pprint, exceptions
from Tkinter import *

def test():
    root = Tk()
    global canvas
    canvas = Canvas(root,height=400,width=500)
    canvas.bind("<Button-1>", StrokeBegin)
    canvas.bind("<B1-Motion>", Stroke)
    canvas.bind("<ButtonRelease-1>", StrokeEnd)    
    canvas.pack()
    root.mainloop()
    # end test()

class NotYetImplementedException(exceptions.Exception):
    pass

def StrokeInit():
    raise NotYetImplementedException, "StrokeInit"
    # end StrokeInit()

def StrokeBegin(event):
    global stroke
    print "clicked at", event.x, event.y
    del stroke[0:] # blank the list
    tuple = (event.x, event.y)
    stroke.append( tuple )
    # end StrokeBegin()

def Stroke(event):
    global stroke
    global canvas
    tuple = event.x, event.y
    coords = []
    coords.append( stroke[len(stroke)-1] )
    coords.append( tuple    )
    
    stroke.append( tuple )    
    stroke.append(tuple)
    x0=(coords[0])[0]
    y0=(coords[0])[1]
    x1=(coords[1])[0]
    y1=(coords[1])[1]
    canvas.create_line(x0,y0,x1,y1,tag='segements')
    # end Stroke()

def StrokeEnd(event):
    global canvas
    global stroke    
    coords=[]
    for a_coord in stroke:
        coords.append(a_coord)
        
    canvas.delete('segments')
    TURN_ON=1
    canvas.create_line(coords,tag='line',arrow=LAST,joinstyle=ROUND,smooth=TURN_ON)
    # end StrokeEnd()

if __name__ == '__main__':
    stroke=[]
    canvas=None
    test()