Widgets in PyGTK

Widgets in PyGTK

In this part of the PyGTK programming tutorial, we will introduce some PyGTK widgets.
Widgets are basic building blocks of a GUI application. Over the years, several widgets became a standard in all toolkits on all OS platforms. For example a button, a check box or a scroll bar. The PyGTK toolkit's philosophy is to keep the number of widgets at a minimum level. More specialized widgets are created as custom PyGTK widgets.

Label

The Label widget displays a limited amount of read-only text.

label.py

#!/usr/bin/python

# ZetCode PyGTK tutorial 
#
# This example demonstrates the Label widget
#
# author: jan bodnar
# website: zetcode.com 
# last edited: February 2009

import gtk

lyrics = """Meet you downstairs in the bar and heard
your rolled up sleeves and your skull t-shirt
You say why did you do it with him today?
and sniff me out like I was Tanqueray

cause you're my fella, my guy
hand me your stella and fly
by the time I'm out the door
you tear men down like Roger Moore

I cheated myself
like I knew I would
I told ya, I was trouble
you know that I'm no good"""


class PyApp(gtk.Window): 
    def __init__(self):
        super(PyApp, self).__init__()
        
        self.set_position(gtk.WIN_POS_CENTER)
        self.set_border_width(8)
        self.connect("destroy", gtk.main_quit)
        self.set_title("You know I'm no Good")
        
        label = gtk.Label(lyrics)
        self.add(label)
        self.show_all()


PyApp()
gtk.main()

The code example shows some lyrics on the window.

lyrics = """Meet you downstairs in the bar and heard
your rolled up sleeves and your skull t-shirt
..."""

This is the text that we display.

 self.set_border_width(8)

The Label is surrounded by some empty space.

 label = gtk.Label(lyrics)
 self.add(label)

The Label widget is created and added to the window.

Figure: Label Widget

CheckButton

CheckButton is a widget, that has two states. On and Off. The On state is visualised by a check mark. It is used to denote some boolean property.

checkbutton.py

#!/usr/bin/python

# ZetCode PyGTK tutorial 
#
# This example demonstrates the CheckButton widget
#
# author: jan bodnar
# website: zetcode.com 
# last edited: February 2009

import gtk

class PyApp(gtk.Window):

    def __init__(self):
        super(PyApp, self).__init__()
        self.set_title("Check Button")
        self.set_position(gtk.WIN_POS_CENTER)
        self.set_default_size(250, 200)

        fixed = gtk.Fixed()
        button = gtk.CheckButton("Show title")
        button.set_active(True)
        button.unset_flags(gtk.CAN_FOCUS)
        button.connect("clicked", self.on_clicked)

        fixed.put(button, 50, 50)

        self.connect("destroy", gtk.main_quit)
        self.add(fixed)
        self.show_all()

    def on_clicked(self, widget):
        if widget.get_active():
            self.set_title("Check Button")
        else:
           self.set_title("")
        
PyApp()
gtk.main()

We will display a title in the titlebar of the window, depending on the state of the CheckButton.

 button = gtk.CheckButton("Show title")

CheckButton widget is created.

 button.set_active(True)

The title is visible by default, so we check the check button by default.

 if widget.get_active():
     self.set_title("Check Button")
 else:
     self.set_title("")

If the CheckButton is checked we show the title. Otherwise we put empty text in the titlebar.

Figure: CheckButton

ComboBox

ComboBox is a widget that allows the user to choose from a list of options.

combobox.py

#!/usr/bin/python

# ZetCode PyGTK tutorial 
#
# This example demonstrates the ComboBox widget
#
# author: jan bodnar
# website: zetcode.com 
# last edited: February 2009

import gtk

class PyApp(gtk.Window):
    def __init__(self):
        super(PyApp, self).__init__()
        
        self.set_title("ComboBox")
        self.set_default_size(250, 200)
        self.set_position(gtk.WIN_POS_CENTER)

        cb = gtk.combo_box_new_text()
        cb.connect("changed", self.on_changed)

        cb.append_text('Ubuntu')
        cb.append_text('Mandriva')
        cb.append_text('Redhat')
        cb.append_text('Gentoo')
        cb.append_text('Mint')
        
        fixed = gtk.Fixed()
        fixed.put(cb, 50, 30)
        self.label = gtk.Label("-")
        fixed.put(self.label, 50, 140)
        self.add(fixed)

        self.connect("destroy", gtk.main_quit)
        self.show_all()


    def on_changed(self, widget):
        self.label.set_label(widget.get_active_text()) 

PyApp()
gtk.main()

The example shows a combo box and a label. The combo box has a list of six options. These are the names of Linux Distros. The label widget shows the selected option from the combo box.

 cb = gtk.combo_box_new_text()

The gtk.combo_box_new_text() function is a convenience function that constructs a new text combo box. It is a ComboBox just displaying strings.

 cb.append_text('Ubuntu')
 cb.append_text('Mandriva')
 cb.append_text('Redhat')
 cb.append_text('Gentoo')
 cb.append_text('Mint')

The ComboBox is filled with textual data.

 self.label.set_label(widget.get_active_text()) 

Inside the on_changed() method, we get the selected text out of the combo box and set it to the label.

Figure: ComboBox

Image

The next example introduces the Image widget. This widget displays pictures.

image.py

#!/usr/bin/python

# ZetCode PyGTK tutorial 
#
# This example demonstrates the Image widget
#
# author: jan bodnar
# website: zetcode.com 
# last edited: February 2009

import gtk

class PyApp(gtk.Window):

    def __init__(self):
        super(PyApp, self).__init__()
        
        self.set_title("Red Rock")
        self.set_position(gtk.WIN_POS_CENTER)
        self.set_border_width(2)

        image = gtk.Image()
        image.set_from_file("redrock.png")

        self.connect("destroy", gtk.main_quit)
        self.add(image)
        self.show_all()

PyApp()
gtk.main()

We show the Red Rock castle in the window.

 image = gtk.Image()

Image widget is created.

 image.set_from_file("redrock.png")

We set a png image to the Image widget. The picture is loaded from the file on the disk.

Figure: Image

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In this chapter, we showed the first pack of basic widgets of the PyGTK programming library.