<page xmlns="http://projectmallard.org/1.0/" xmlns:its="http://www.w3.org/2005/11/its" xmlns:xi="http://www.w3.org/2001/XInclude" type="guide" style="task" id="colorbutton.py" xml:lang="de">

  <info>

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

    <link type="guide" xref="beginner.py#color-selectors"/>

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

    <revision version="0.1" date="2012-06-03" status="draft"/>

    <credit type="author copyright">

      <name>Marta Maria Casetti</name>

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

      <years>2012</years>

    </credit>

    <desc>A button to launch a color selection dialog</desc>

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

      <mal:name>Mario Blättermann</mal:name>

      <mal:email>mario.blaettermann@gmail.com</mal:email>

      <mal:years>2011, 2013</mal:years>

    </mal:credit>

  </info>

  <title>ColorButton</title>

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

  
This ColorButton launches a color selection dialog and prints in the terminal the RGB values of the color selected.

  <links type="sections"/>

  <section id="code">

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

  from gi.repository import Gtk

from gi.repository import Gdk

import sys

class MyWindow(Gtk.ApplicationWindow):

    def __init__(self, app):

        Gtk.Window.__init__(self, title="ColorButton", application=app)

        self.set_default_size(150, 50)

        self.set_border_width(10)

        # a colorbutton (which opens a dialogue window in

        # which we choose a color)

        self.button = Gtk.ColorButton()

        # with a default color (blue, in this instance)

        color = Gdk.RGBA()

        color.red = 0.0

        color.green = 0.0

        color.blue = 1.0

        color.alpha = 0.5

        self.button.set_rgba(color)

        # choosing a color in the dialogue window emits a signal

        self.button.connect("color-set", self.on_color_chosen)

        # a label

        label = Gtk.Label()

        label.set_text("Click to choose a color")

        # a grid to attach button and label

        grid = Gtk.Grid()

        grid.attach(self.button, 0, 0, 2, 1)

        grid.attach(label, 0, 1, 2, 1)

        self.add(grid)

    # if a new color is chosen, we print it as rgb(r,g,b) in the terminal

    def on_color_chosen(self, user_data):

        print("You chose the color: " + self.button.get_rgba().to_string())

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)

  </section>

  <section id="methods">

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

  
set_color(color), where the color is defined as in the example, sets the color of the ColorButton, which by default is black. get_color() returns the color.

    
In line 23 the "color-set" signal is connected to the callback function on_color_chosen() using widget.connect(signal, callback function). See <link xref="signals-callbacks.py"/> for a more detailed explanation.

  </section>

  <section id="references">

  <title>API-Referenzen</title>

  
In this sample we used the following:

  <list>

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

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

    <item>
<link href="http://developer.gnome.org/gdk3/stable/gdk3-RGBA-Colors.html">RGBA-Farben</link>
</item>

  </list>

  </section>

</page>