Mega Code Archive

 

Categories / Python / GUI Tk

 

Use mouse to draw a shape on canvas

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()