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<?xml version="1.0" encoding="utf-8"?>
<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="widget_drawing.py" xml:lang="fr">
<info>
<title type="text">Widget (Python)</title>
<link type="guide" xref="beginner.py#misc"/>
<revision version="0.1" date="2013-02-24" status="stub"/>
<credit type="author copyright">
<name>Marta Maria Casetti</name>
<email its:translate="no">mmcasetti@gmail.com</email>
<years>2013</years>
</credit>
<desc>A widget that uses the Cairo library to draw</desc>
<mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
<mal:name>Luc Rebert,</mal:name>
<mal:email>traduc@rebert.name</mal:email>
<mal:years>2011</mal:years>
</mal:credit>
<mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
<mal:name>Alain Lojewski,</mal:name>
<mal:email>allomervan@gmail.com</mal:email>
<mal:years>2011-2012</mal:years>
</mal:credit>
<mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
<mal:name>Luc Pionchon</mal:name>
<mal:email>pionchon.luc@gmail.com</mal:email>
<mal:years>2011</mal:years>
</mal:credit>
<mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
<mal:name>Bruno Brouard</mal:name>
<mal:email>annoa.b@gmail.com</mal:email>
<mal:years>2011-12</mal:years>
</mal:credit>
<mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
<mal:name>Luis Menina</mal:name>
<mal:email>liberforce@freeside.fr</mal:email>
<mal:years>2014</mal:years>
</mal:credit>
</info>
<title>Widget</title>
<media type="image" mime="image/png" src="media/widget_drawing.png"/>
<p>Enter an angle, visualize it.</p>
<links type="section"/>
<section id="code">
<title>Code utilisé pour générer cet exemple</title>
<code mime="text/x-python" style="numbered">from gi.repository import Gtk
from gi.repository import cairo
import sys
import math
class MyWindow(Gtk.ApplicationWindow):
def __init__(self, app):
Gtk.Window.__init__(self, title="Choose an angle", application=app)
self.set_default_size(400, 400)
self.set_border_width(10)
# a default angle
self.angle = 360
grid = Gtk.Grid()
# a spinbutton that takes the value of an angle
ad = Gtk.Adjustment(360, 0, 360, 1, 0, 0)
self.spin = Gtk.SpinButton(adjustment=ad, climb_rate=1, digits=0)
self.spin.connect("value-changed", self.get_angle)
# a drawing area for drawing whatever we want
self.darea = Gtk.DrawingArea()
# that we describe in the method draw(), connected to the signal "draw"
self.darea.connect("draw", self.draw)
# we have to request a minimum size of the drawing area, or it will
# disappear
self.darea.set_size_request(300, 300)
grid.attach(self.spin, 0, 0, 1, 1)
grid.attach(self.darea, 0, 1, 1, 1)
self.add(grid)
# whenever we get a new angle in the spinbutton
def get_angle(self, event):
self.angle = self.spin.get_value_as_int()
# redraw what is in the drawing area
self.darea.queue_draw()
def draw(self, darea, cr):
# a 10-pixels-wide line
cr.set_line_width(10)
# red
cr.set_source_rgba(0.5, 0.0, 0.0, 1.0)
# get the width and height of the drawing area
w = self.darea.get_allocated_width()
h = self.darea.get_allocated_height()
# move to the center of the drawing area
# (translate from the top left corner to w/2, h/2)
cr.translate(w / 2, h / 2)
# draw a line to (55, 0)
cr.line_to(55, 0)
# and get back to (0, 0)
cr.line_to(0, 0)
# draw an arc centered in the origin, 50 pixels wide, from the angle 0
# (in radians) to the angle given by the spinbutton (in degrees)
cr.arc(0, 0, 50, 0, self.angle * (math.pi / 180))
# draw a line back to the origin
cr.line_to(0, 0)
# drawing the path, and keeping the path for future use
cr.stroke_preserve()
# set a colour
cr.set_source_rgba(0.0, 0.5, 0.5, 1.0)
# and use it to fill the path (that we had kept)
cr.fill()
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)
</code>
</section>
<section id="references">
<title>Références API</title>
<p>Dans cet exemple, les éléments suivants sont utilisés :</p>
<list>
<item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkWidget.html">GtkWidget</link></p></item>
<item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkDrawingArea.html">GtkDrawingArea</link></p></item>
<item><p><link href="http://www.tortall.net/mu/wiki/CairoTutorial">The Cairo Tutorial for Python Programmers</link></p></item>
</list>
</section>
</page>
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