15.27. Common Widget Properties

Each widget has a set of properties that define its visual appearance on the computer screen and how it responds to user events. There is a set of properties that all tk widgets have in common. Some of these are shown in the following table.

Common Widget Properties

Description

bg

Background color.

fg

Foreground color.

width

Width in pixels

height

Height in pixels

borderwidth

The size of the border in pixels.

text

Text displayed on the widget.

font

The font used for text on the widget.

cursor

The shape of the cursor when the cursor is over the widget.

activeforeground

The color of the text when the widget is activated.

activebackground

The color of the background when the widget is activated.

image

An image to be displayed on the widget.

You can treat a widget object as a dictionary and use the property names as keys to access and change the property values. For example, to change the background color and width of a widget whose object variable is named sam, you could do this:

sam = tk.Button(application_window, text="Sam's Button")
sam['bg'] = 'red'
sam['width'] = 60  # pixels

15.28. Specific Widget Properties

Each type of widget has properties specific to its intended use. Here are some examples:

Specific Widget Properties

Applies to

Description

variable

Checkbutton Radiobutton Entry Spinbox Text

An Tk object that will be changed by interaction with the widget.

from_

Scale

The starting value of a scale (i.e., a slider)

to

Scale

The ending value of a scale (i.e., a slider)

orient

Scale

HORIZONTAL or VERTICAL

resolution

Scale

The increment amount along a scale (i.e., a slider)

Some widgets have a “variable” that a user manipulates. For such widgets you must create a special tk object that stores the widget’s value. Basically you are creating a non-visible widget that can have events associated with it. You can access the widget’s value through .set(new_value) and .get() methods on the variable object. There are four types of variable objects:

tk variable object

Description

tk.BooleanVar

A tk object that holds a single Boolean value

tk.IntVar

A tk object that holds a single integer value

tk.DoubleVar

A tk object that holds a single double value

tk.StringVar

A tk object that holds a single string value

Let’s take a tk.Checkbutton as an example and walk through the steps needed to get and set its “value”. You need to do three things:

  1. Create a tk.BooleanVar object. (Actually any type of variable object can be used.)

  2. Give the tk.BooleanVar object the initial value you want for the checkbutton.

  3. Assign the variable attribute of the checkbutton to the tk.BooleanVar object.

In code this looks like this:

checkbutton_value = tk.BooleanVar()
checkbutton_value.set(True)  # The checkbutton will be "checked"

my_checkbutton = tk.Checkbutton(parent_widget, text="Example check box")
my_checkbutton['variable'] = checkbutton_value

If you want the value of the checkbutton at any time while your program is running, you get the value of the variable object like this:

the_current_value_of_the_checkbutton = checkbutton_value.get()

And you can change the state of the checkbutton at any time using a call to .set() like this:

checkbutton_value.set(FALSE)  # set the checkbutton to "un-checked"

15.29. Widget Attributes

The following web pages provide a good description of the properties that can be modified for individual widgets:

Widget

Documentation Resource

tk.Button

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/button.html

ttk.Button

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Button.html

tk.Menu

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/menu.html

tk.Menubutton

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/menubutton.html

ttk.Menubutton

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Menubutton.html

tk.OptionMenu

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/optionmenu.html

ttk.Entry

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Entry.html

tk.Text

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/text.html

tk.Checkbutton

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/radiobutton.html

ttk.Checkbutton

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Checkbutton.html

tk.Radiobutton

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/radiobutton.html

ttk.Radiobutton

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Radiobutton.html

tk.Listbox

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/listbox.html

ttk.Combobox

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Combobox.html

tk.Scale

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/scale.html

ttk.Scale

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Scale.html

Container Widgets

tk.Frame

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/frame.html

ttk.Frame

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Frame.html

tk.LabelFrame

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/labelframe.html

ttk.LabelFrame

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-LabelFrame.html

tk.PanedWindow

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/panedwindow.html

ttk.PanedWindow

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-PanedWindow.html

ttk.Notebook

http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-Notebook.html

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