Now we make a program that tests each possible mouse event that Python is capable of responding to.
Execute the program shown in the normal way.
# all_mouse_actions_1.py
#>>>>>>>>>>>>>>>>>>
from Tkinter import *
root = Tk()
root.title("Mouse follower")
# The Canvas here is bound to the mouse events
cw = 200 # canvas width
ch = 100 # canvas height
chart_1 = Canvas(root, width=cw, height=ch, background="#ffffff")
chart_1.grid(row=1, column=1)
#========= Left Mouse Button Events ===============
# callback events
def callback_1(event):
print "left mouse clicked"
def callback_2(event):
print "left dragged"
def callback_3(event):
print "left doubleclick"
def callback_4(event):
print "left released"
#======== Center Mouse Button Events ======================
def callback_5(event):
print "center mouse clicked"
def callback_6(event):
print "center dragged"
def callback_7(event):
print "center doubleclick"
def callback_8(event):
print "center released"
#======== Right Mouse Button Events ======================
def callback_9(event):
print "right mouse clicked"
def callback_10(event):
print "right dragged"
def callback_11(event):
print "right doubleclick"
def callback_12(event):
print "right released"
# <button-1> is the left mouse button
chart_1.bind("<Button-1>", callback_1)
chart_1.bind("<B1-Motion>", callback_2)
chart_1.bind("<Double-1>", callback_3)
chart_1.bind("<ButtonRelease-1>", callback_4)
# <button-2> is the center mouse button
chart_1.bind("<Button-2>", callback_5)
chart_1.bind("<B2-Motion>", callback_6)
chart_1.bind("<Double-2>", callback_7)
chart_1.bind("<ButtonRelease-2>", callback_8)
# <button-3> is the right mouse button
chart_1.bind("<Button-3>", callback_9)
chart_1.bind("<B3-Motion>", callback_10)
chart_1.bind("<Double-3>", callback_11)
chart_1.bind("<ButtonRelease-3>", callback_12)
root.mainloop()
#>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The preceding code is reasonably self-explanatory. A small canvas is created that is responsive to all the mouse actions. Proof that the responses are working correctly are by means of confirmation messages typed on the system console. We can adapt the callback functions to do any kind of task we choose simply by inserting appropriate Python commands into the callback functions.
Mouse events and Tkinter widgets often work together. Most Tkinter GUI widgets are designed to be controlled by mouse events such as left or right-clicks or dragging with a button held down. Tkinter provides a versatile selection of widgets and these will be explored in Chapter 10, GUI Construction Part 1 and Chapter 11, GUI Construction