6. Label

Labels are the main method of placing non-editable text in windows, for instance to place a title next to a Gtk.Entry widget. You can specify the text in the constructor, or later with the Gtk.Label.set_text() or Gtk.Label.set_markup() methods.

The width of the label will be adjusted automatically. You can produce multi-line labels by putting line breaks (“\n”) in the label string.

Labels can be made selectable with Gtk.Label.set_selectable(). Selectable labels allow the user to copy the label contents to the clipboard. Only labels that contain useful-to-copy information — such as error messages — should be made selectable.

The label text can be justified using the Gtk.Label.set_justify() method. The widget is also capable of word-wrapping, which can be activated with Gtk.Label.set_line_wrap().

Gtk.Label support some simple formatting, for instance allowing you to make some text bold, colored, or larger. You can do this by providing a string to Gtk.Label.set_markup(), using the Pango Markup syntax [1]. For instance, <b>bold text</b> and <s>strikethrough text</s>. In addition, Gtk.Label supports clickable hyperlinks. The markup for links is borrowed from HTML, using the a with href and title attributes. GTK+ renders links similar to the way they appear in web browsers, with colored, underlined text. The title attribute is displayed as a tooltip on the link.

label.set_markup("Go to <a href=\"http://www.gtk.org\" "
                 "title=\"Our website\">GTK+ website</a> for more")

Labels may contain mnemonics. Mnemonics are underlined characters in the label, used for keyboard navigation. Mnemonics are created by providing a string with an underscore before the mnemonic character, such as “_File”, to the functions Gtk.Label.new_with_mnemonic() or Gtk.Label.set_text_with_mnemonic(). Mnemonics automatically activate any activatable widget the label is inside, such as a Gtk.Button; if the label is not inside the mnemonic’s target widget, you have to tell the label about the target using Gtk.Label.set_mnemonic_widget().

6.1. Example

_images/label_example.png
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from gi.repository import Gtk

class LabelWindow(Gtk.Window):

    def __init__(self):
        Gtk.Window.__init__(self, title="Label Example")
        
        hbox = Gtk.Box(spacing=10)
        hbox.set_homogeneous(False)
        vbox_left = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=10)
        vbox_left.set_homogeneous(False)
        vbox_right = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=10)
        vbox_right.set_homogeneous(False)
        
        hbox.pack_start(vbox_left, True, True, 0)
        hbox.pack_start(vbox_right, True, True, 0)
        
        label = Gtk.Label("This is a normal label")
        vbox_left.pack_start(label, True, True, 0)
        
        label = Gtk.Label()
        label.set_text("This is a left-justified label.\nWith multiple lines.")
        label.set_justify(Gtk.Justification.LEFT)
        vbox_left.pack_start(label, True, True, 0)
        
        label = Gtk.Label(
            "This is a right-justified label.\nWith multiple lines.")
        label.set_justify(Gtk.Justification.RIGHT)
        vbox_left.pack_start(label, True, True, 0)
        
        label = Gtk.Label("This is an example of a line-wrapped label.  It "
                          "should not be taking up the entire             "
                          "width allocated to it, but automatically "
                          "wraps the words to fit.\n"
                          "     It supports multiple paragraphs correctly, "
                          "and  correctly   adds "
                          "many          extra  spaces. ")
        label.set_line_wrap(True)
        vbox_right.pack_start(label, True, True, 0)
        
        label = Gtk.Label("This is an example of a line-wrapped, filled label. "
                          "It should be taking "
                          "up the entire              width allocated to it.  "
                          "Here is a sentence to prove "
                          "my point.  Here is another sentence. "
                          "Here comes the sun, do de do de do.\n"
                          "    This is a new paragraph.\n"
                          "    This is another newer, longer, better "
                          "paragraph.  It is coming to an end, "
                          "unfortunately.")
        label.set_line_wrap(True)
        label.set_justify(Gtk.Justification.FILL)
        vbox_right.pack_start(label, True, True, 0)

        label = Gtk.Label()
        label.set_markup("Text can be <small>small</small>, <big>big</big>, "
                         "<b>bold</b>, <i>italic</i> and even point to "
                         "somewhere in the <a href=\"http://www.gtk.org\" "
                         "title=\"Click to find out more\">internets</a>.")
        label.set_line_wrap(True)
        vbox_left.pack_start(label, True, True, 0)

        label = Gtk.Label.new_with_mnemonic(
            "_Press Alt + P to select button to the right")
        vbox_left.pack_start(label, True, True, 0)
        label.set_selectable(True)

        button = Gtk.Button(label="Click at your own risk")
        label.set_mnemonic_widget(button)
        vbox_right.pack_start(button, True, True, 0)

        self.add(hbox)

window = LabelWindow()        
window.connect("delete-event", Gtk.main_quit)
window.show_all()
Gtk.main()
[1]Pango Markup Syntax, http://developer.gnome.org/pango/stable/PangoMarkupFormat.html