<page xmlns="http://projectmallard.org/1.0/" xmlns:its="http://www.w3.org/2005/11/its" xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:e="http://projectmallard.org/experimental/" type="guide" style="task" id="label.py" xml:lang="pt-BR">

  <info>

    <title type="text">Label (Python)</title>

    <link type="guide" xref="beginner.py#display-widgets"/>

    <link type="seealso" xref="properties.py"/>

    <link type="seealso" xref="strings.py"/>

    <link type="next" xref="properties.py"/>

    <revision version="0.2" date="2012-06-18" status="draft"/>

    <credit type="author copyright">

      <name>Marta Maria Casetti</name>

      <email its:translate="no">mmcasetti@gmail.com</email>

      <years>2012</years>

    </credit>

    <credit type="author">

      <name>Sebastian Pölsterl</name>

      <email its:translate="no">sebp@k-d-w.org</email>

      <years>2012</years>

    </credit>

    <desc>A widget that displays a small to medium amount of text</desc>

    <mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">

      <mal:name>Rafael Ferreira</mal:name>

      <mal:email>rafael.f.f1@gmail.com</mal:email>

      <mal:years>2013</mal:years>

    </mal:credit>

  </info>

  <title>Label</title>

  <media type="image" mime="image/png" src="media/label.png"/>

  
A simple label

  <links type="section"/>

  <section id="code">

  <title>Code used to generate this example</title>

  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:

    <note>

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

    </note>

# 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

<e:hi>

class MyLabel(Gtk.Label):

    def __init__(self):

        Gtk.Label.__init__(self)

        self.set_text("Hello GNOME!")

</e:hi>

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

<e:hi>

        label = MyLabel()

</e:hi>

        # and add it to the window

<e:hi>

        win.add(label)

</e:hi>

        # show the window and everything on it

        win.show_all()

  </section>

  <section id="methods">

  <title>Useful methods for a Label widget</title>

  <note style="tip">

    
An explanation of how to work with strings in GTK+ can be found in <link xref="strings.py"/>.

  </note>

  <list>

    <item>
set_line_wrap(True) breaks lines if the text of the label exceeds the size of the widget.
</item>

    <item>
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.
</item>

    <item>
For decorated text we can use set_markup("text"), where "text" is a text in the <link href="http://developer.gnome.org/pango/stable/PangoMarkupFormat.html">Pango Markup Language</link>. An example:

label.set_markup("Text can be <small>small</small>, <big>big</big>, "

                 "bold, italic and even point to somewhere "

                 "on the 

                 "title=\"Click to find out more\">internet.")]]>

    </item>

  </list>

  </section>

  <section id="references">

  <title>API References</title>

  
In this sample we used the following:

  <list>

    <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkLabel.html">GtkLabel</link>
</item>

    <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkWindow.html">GtkWindow</link>
</item>

  </list>

  </section>

</page>