<< plib_gui

tkinter

1. Window Control

# mainloop

tkinter is the bulit-in GUI library for Python. Here is how to create a root window:

from tkinter import Tk
root = Tk()
root.mainloop()

We initialize an instance root from class Tk, which represents a window, and then use mainloop to keep it shown.

# Window Property

The title and size of the window can be reset by the title and geometry method of Tk object:

root.title('window example')
root.geometry("500x200")

Notice that the parameter of the size of window is a string, which is absoluately a strange old-fashion design.

# Event bind

If you want to track the IO event over the window, use bind to active a callback function:

def show_click_cord(event):
    print(event.x, event.y)

def show_key(event):
    print(event.char)


root.bind('<Button-1>', show_click_cord)
root.bind('<Key>', show_key)
# Notice that the since the function is passed as a parameter, do not add tailing brackets () otherwise it will be executed.

Here we bind a left-click event(<Button-1>) and keypress event(<Key>) to function show_click_cord and show_key respectively, which receive a argument event that containing the information about the event, i.e. (x,y) coordinate for click event and key value for keyboard event.

Here the 1 inside <Button-1> indicates the left-click, and 2 for middle, 3 for right respectively.

There’re some more event like

• <B1-Motion>: the movement and hold down of left-click.

• <ButtonRelease-1>: the release of left-click.

• <Enter>: the cursor enter the widget. Notice this doesn’t mean the Enter key is pressed, the Enter key is represented by <Return> instead!

There’re more events, which cloud be referred in ==todo: url==.