draw.py

from Tkinter import *

class PaintBox( Frame ):
   def __init__( self ):
      Frame.__init__( self )
      self.pack( expand = YES, fill = BOTH )
      self.master.title( "A simple paint program" )
      self.master.geometry( "300x150" )

      self.message = Label( self, text = "Drag the mouse to draw" )
      self.message.pack( side = BOTTOM )
      
      # create Canvas component
      self.myCanvas = Canvas( self )
      self.myCanvas.pack( expand = YES, fill = BOTH )

      # bind mouse dragging event to Canvas
      self.myCanvas.bind( "<B1-Motion>", self.paint )

   def paint( self, event ):
      x1, y1 = ( event.x - 4 ), ( event.y - 4 )
      x2, y2 = ( event.x + 4 ), ( event.y + 4 )
      self.myCanvas.create_oval( x1, y1, x2, y2, fill = "red" )
   
def main():
   PaintBox().mainloop()

if __name__ == "__main__":
   main()