Mouse event - binding

[John McMonagle]

On Tue, 2006-04-04 at 14:46 -0700, beta wrote:
> Hello All,
> 
> I am new with Python, your help would be very appreciated.
> 
> I have a simple pinpong applicaiton. I would like make a ball's color
> change when mouse is clicked on it.
> 
> Here is my sample code:
> 
> from Tkinter import *
> 
> import string
> 
> 
> class Pong(Frame):
>     def createWidgets(self):
>         self.QUIT = Button(self, text='QUIT', foreground='red',
>                            command=self.quit)
>         self.QUIT.pack(side=LEFT, fill=BOTH)
> 
>         ## The playing field
>         self.draw = Canvas(self, width="5i", height="5i")
> 
>         ## The speed control for the ball
>         self.speed = Scale(self, orient=HORIZONTAL, label="ball speed",
>                            from_=-100, to=100)
> 
>         self.speed.pack(side=BOTTOM, fill=X)
> 
>         # The ball
>         #self.ball = self.draw.create_oval("0i", "0i", "0.10i",
> "0.10i",
>         #                                  fill="red")
>         self.theBall()
>         self.x = 0.05
>         self.y = 0.05
>         self.velocity_x = 0.3
>         self.velocity_y = 0.5
> 
>         self.draw.pack(side=LEFT)
>     def theBall(self):
>          self.ball = self.draw.create_oval("0i", "0i", "0.20i",
> "0.20i",
>                                           fill="red")
> 
>     def moveBall(self, *args):
>         if (self.x > 5.0) or (self.x < 0.0):
>             self.velocity_x = -1.0 * self.velocity_x
>         if (self.y > 5.0) or (self.y < 0.0):
>             self.velocity_y = -1.0 * self.velocity_y
> 
>         deltax = (self.velocity_x * self.speed.get() / 100.0)
>         deltay = (self.velocity_y * self.speed.get() / 100.0)
>         self.x = self.x + deltax
>         self.y = self.y + deltay
> 
>         self.draw.move(self.ball,  "%ri" % deltax, "%ri" % deltay)
>         self.after(10, self.moveBall)
> 
>     def __init__(self, master=None):
>         Frame.__init__(self, master)
>         Pack.config(self)
>         self.createWidgets()
>         self.after(10, self.moveBall)
> 
> 
> game = Pong()
> 
> game.mainloop()
> 
> Thanks,
> 
> -- 

You need to bind a button-1 event to the ball tag.  After you initially
create the ball item:

self.draw.tag_bind(self.ball, '<Button-1>', changeColour)

where changeColour is a function like so:

    def changeColour(self, event):
        x = self.draw.canvasx(event.x)
        y = self.draw.canvasy(event.y)
        item = self.draw.find_closest(x,y)
        currentColour = self.draw.itemcget(item, 'fill')
        if currentColour == 'red':
            self.draw.itemconfigure(item, fill='blue')
        else:
            self.draw.itemconfigure(item, fill='red')

This will toggle the ball colour between red and blue.

HTH,

John McMonagle



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