eventBasedAnimationClass.py

# eventBasedAnimationClass.py
# This is modified from class notes

from Tkinter import *


class EventBasedAnimationClass(object):
    def onMousePressed(self, event):
        pass

    def onKeyPressed(self, event):
        pass

    def onTimerFired(self):
        pass

    def redrawAll(self):
        pass

    def initAnimation(self):
        pass

    def __init__(self, width=300, height=300):
        self.width = width
        self.height = height
        self.timerDelay = 250  # in milliseconds (set to None to turn off timer)

    def onMousePressedWrapper(self, event):
        self.onMousePressed(event)
        self.redrawAll()

    def onKeyPressedWrapper(self, event):
        self.onKeyPressed(event)
        self.redrawAll()

    def onTimerFiredWrapper(self):
        if self.timerDelay is None:
            return  # turns off timer
        self.onTimerFired()
        self.redrawAll()
        self.canvas.after(self.timerDelay, self.onTimerFiredWrapper)

    def handler(self):
        exit(-1)

    def run(self):
        # create the root and the canvas
        self.root = Tk()
        self.root.wm_title("Stream by Chen Liang")
        self.canvas = Canvas(self.root, width=self.width, height=self.height)
        self.canvas.pack()
        self.initAnimation()
        # set up events
        # DK: You can use a local function with a closure
        # to store the canvas binding, like this:

        def f(event):
            self.onMousePressedWrapper(event)

        self.root.bind("<Button-1>", f)
        # DK: Or you can just use an anonymous lamdba function, like this:
        self.root.bind("<KeyPress>",
                       lambda event: self.onKeyPressedWrapper(event))
        self.onTimerFiredWrapper()
        # and launch the app (This call BLOCKS, so your program waits
        # until you close the window!)
        self.root.protocol("WM_DELETE_WINDOW", self.handler)

        self.root.mainloop()

# EventBasedAnimationClass(300,300).run()