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from Tkinter import *
trace = 0
class CanvasEventsDemo:
def __init__(self, parent=None):
canvas = Canvas(width=300, height=300, bg='beige')
canvas.pack()
canvas.bind('<ButtonPress-1>', self.onStart)
canvas.bind('<B1-Motion>', self.onGrow)
canvas.bind('<Double-1>', self.onClear)
canvas.bind('<ButtonPress-3>', self.onMove)
self.canvas = canvas
self.drawn = None
self.kinds = [canvas.create_oval, canvas.create_rectangle]
def onStart(self, event):
self.shape = self.kinds[0]
self.kinds = self.kinds[1:] + self.kinds[:1]
self.start = event
self.drawn = None
def onGrow(self, event):
canvas = event.widget
if self.drawn: canvas.delete(self.drawn)
objectId = self.shape(self.start.x, self.start.y, event.x, event.y)
if trace: print objectId
self.drawn = objectId
def onClear(self, event):
event.widget.delete('all')
def onMove(self, event):
if self.drawn:
if trace: print self.drawn
canvas = event.widget
diffX, diffY = (event.x - self.start.x), (event.y - self.start.y)
canvas.move(self.drawn, diffX, diffY)
self.start = event
if __name__ == '__main__':
CanvasEventsDemo()
mainloop()
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