# Label (Python)

Marta Maria Casetti
mmcasetti@gmail.com 2012
Sebastian Pölsterl
sebp@k-d-w.org 2012
A widget that displays a small to medium amount of text
Anders Jonsson
anders.jonsson@norsjovallen.se 2018

# Label

A simple label

# Code used to generate this example

from gi.repository import Gtk import sys

class MyWindow(Gtk.ApplicationWindow): # constructor for a Gtk.ApplicationWindow

def __init__(self, app): Gtk.Window.__init__(self, title="Welcome to GNOME", application=app) self.set_default_size(200, 100)

# create a label label = Gtk.Label() # set the text of the label label.set_text("Hello GNOME!") # add the label to the window self.add(label)

class MyApplication(Gtk.Application):

def __init__(self): Gtk.Application.__init__(self)

def do_activate(self): win = MyWindow(self) win.show_all()

def do_startup(self): Gtk.Application.do_startup(self)

app = MyApplication() exit_status = app.run(sys.argv) sys.exit(exit_status)

Another way to obtain what we have in the example is to create the label as an instance of another class and add it to the instance of `MyWindow` in the `do_activate(self)` method:

The highlighted lines indicate code that is different from the previous snippet.

# a class to define a window class MyWindow(Gtk.ApplicationWindow): def __init__(self, app): Gtk.Window.__init__(self, title="Welcome to GNOME", application=app) self.set_default_size(200, 100)

# a class to define a label class MyLabel(Gtk.Label): def __init__(self): Gtk.Label.__init__(self) self.set_text("Hello GNOME!")

class MyApplication(Gtk.Application): def __init__(self): Gtk.Application.__init__(self)

def do_activate(self): # create an instance of MyWindow win = MyWindow(self)

# create an instance of MyLabel label = MyLabel() # and add it to the window win.add(label) # show the window and everything on it win.show_all()

# Useful methods for a Label widget

An explanation of how to work with strings in GTK+ can be found in .

`set_line_wrap(True)` breaks lines if the text of the label exceeds the size of the widget.

`set_justify(Gtk.Justification.LEFT)` (or `Gtk.Justification.RIGHT, Gtk.Justification.CENTER, Gtk.Justification.FILL`) sets the alignment of the lines in the text of the label relative to each other. The method has no effect on a single-line label.

For decorated text we can use `set_markup("text")`, where `"text"` is a text in the Pango Markup Language. An example:

label.set_markup("Text can be <small>small</small>, <big>big</big>, " "<b>bold</b>, <i>italic</i> and even point to somewhere " "on the <a href=\"http://www.gtk.org\" " "title=\"Click to find out more\">internet</a>.")

# API-referenser

In this sample we used the following:

GtkLabel

GtkWindow