GTK+ 3: Vektorgrafiken mit Cairo
Hier zunächst nur ein einfaches Beispiel, wie man mit GtkDrawingArea und Cairo eine Vektorgrafik anzeigen lassen kann:
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- #!/usr/bin/python3
- # -*- coding: utf-8 -*-
- import cairo, math, gi
- gi.require_version('Gtk', '3.0')
- from gi.repository import Gtk
- class MainWindow(Gtk.Window):
- def __init__(self):
- Gtk.Window.__init__(self, title="Zeichnen mit Cairo")
- self.set_position(Gtk.WindowPosition.CENTER)
- self.set_default_size(400, 400)
- self.box01 = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, homogeneous=False, spacing=5)
- self.add(self.box01)
- self.button01 = Gtk.Button("Klick mich!")
- self.button01.connect('clicked', self.on_button01_clicked)
- self.box01.pack_start(self.button01, False, False, 0)
- self.drawingarea01 = Gtk.DrawingArea()
- self.drawingarea01.connect('draw', self.draw_something)
- self.box01.pack_start(self.drawingarea01, True, True, 0)
- self.show_all()
- self.smile = True
- def on_button01_clicked(self, widget):
- if self.smile == True:
- self.smile = False
- else:
- self.smile = True
- self.drawingarea01.queue_draw() # Bewirkt ein Neuzeichnen der Grafik
- def draw_something(self, widget, cr):
- x = 200
- y = 200
- cr.set_source_rgb(1, 1, 0)
- cr.arc(x, y, 100, 0, 2 * math.pi)
- cr.fill_preserve()
- cr.set_source_rgb(0, 0, 0)
- cr.stroke()
- cr.arc(x - 40, y - 30, 20, 0, 2 * math.pi)
- cr.arc(x + 40, y - 30, 20, 0, 2 * math.pi)
- cr.fill()
- cr.set_line_width(10)
- cr.set_line_cap(cairo.LINE_CAP_ROUND)
- if self.smile == True:
- cr.arc(x, y, 60, math.pi / 4, math.pi * 3 / 4)
- else:
- cr.arc(x, y + 100, 60, math.pi * 5 / 4, math.pi * 7 / 4)
- cr.stroke()
- win = MainWindow()
- win.connect("delete-event", Gtk.main_quit)
- Gtk.main()