[pygobject] [gi-demos] add pixbuf demo

[John Palmieri <johnp src gnome org>]

commit 13b06170b89b3468e6255be32af4833ffc675c9d
Author: John (J5) Palmieri <johnp redhat com>
Date:   Thu Feb 17 14:48:24 2011 -0500

    [gi-demos] add pixbuf demo

 demos/gtk-demo/demos/pixbuf.py |  183 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 183 insertions(+), 0 deletions(-)
---
diff --git a/demos/gtk-demo/demos/pixbuf.py b/demos/gtk-demo/demos/pixbuf.py
new file mode 100644
index 0000000..4a9aa58
--- /dev/null
+++ b/demos/gtk-demo/demos/pixbuf.py
@@ -0,0 +1,183 @@
+#!/usr/bin/env python
+# -*- Mode: Python; py-indent-offset: 4 -*-
+# vim: tabstop=4 shiftwidth=4 expandtab
+#
+# Copyright (C) 2010 Red Hat, Inc., John (J5) Palmieri <johnp redhat com>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
+# USA
+
+title = "Pixbufs"
+description = """A GdkPixbuf represents an image, normally in RGB or RGBA format. Pixbufs are normally used to load files from disk and perform image scaling.
+ It also shows off how to use GtkDrawingArea to do a simple animation.
+Look at the Image demo for additional pixbuf usage examples.
+"""
+
+from gi.repository import Gtk, Gdk, GdkPixbuf, GLib, GObject
+import os
+import math
+from os import path
+
+class PixbufApp:
+    FRAME_DELAY = 50
+    BACKGROUND_NAME = "background.jpg"
+    CYCLE_LEN = 60
+    
+    def __init__(self):
+        self.background_width = 0
+        self.background_height = 0
+        self.background_pixbuf = None
+        self.frame = None
+        self.frame_num = 0
+        self.pixbufs = []
+        self.image_names = [
+            "apple-red.png",
+            "gnome-applets.png",
+            "gnome-calendar.png",
+            "gnome-foot.png",
+            "gnome-gmush.png",
+            "gnome-gimp.png",
+            "gnome-gsame.png",
+            "gnu-keys.png"
+        ]
+
+        self.window = Gtk.Window(title="Pixbufs")
+        self.window.set_resizable(False)
+        self.window.connect('destroy', self.cleanup_cb)
+
+        try:
+            self.load_pixbufs()
+        except GLib.Error as e:
+            dialog = Gtk.MessageDialog(None,
+                                       0,
+                                       Gtk.MessageType.ERROR,
+                                       Gtk.ButtonsType.CLOSE,
+                                       e.message)
+ 
+            dialog.run()
+            dialog.destroy()
+            Gtk.main_quit()
+        
+        self.window.set_size_request(self.background_width,
+                                     self.background_height)
+        self.frame = GdkPixbuf.Pixbuf.new(GdkPixbuf.Colorspace.RGB, 
+                                          False, 
+                                          8,
+                                          self.background_width,
+                                          self.background_height)
+        self.da = Gtk.DrawingArea()
+        self.da.connect('draw', self.draw_cb)
+        self.window.add(self.da)
+        self.timeout_id = GObject.timeout_add(self.FRAME_DELAY, self.timeout_cb)
+        self.window.show_all()
+        
+    def load_pixbufs(self):
+        base_path = 'data'
+        if not path.isdir(base_path):
+            base_path = path.join('demos', base_path)
+
+        img_path = path.join(base_path, self.BACKGROUND_NAME)
+        self.background_pixbuf = GdkPixbuf.Pixbuf.new_from_file(img_path)
+        self.background_height = self.background_pixbuf.get_height()
+        self.background_width = self.background_pixbuf.get_width()
+
+        for img_name in self.image_names:
+            img_path = path.join(base_path, img_name)
+            self.pixbufs.append(GdkPixbuf.Pixbuf.new_from_file(img_path))
+
+    def draw_cb(self, da, cairo_ctx):
+        Gdk.cairo_set_source_pixbuf(cairo_ctx, self.frame, 0, 0)
+        cairo_ctx.paint()
+
+        return True
+
+    def timeout_cb(self):
+        self.background_pixbuf.copy_area(0, 0,
+                                         self.background_width,
+                                         self.background_height,
+                                         self.frame,
+                                         0, 0)
+
+        f = float(self.frame_num % self.CYCLE_LEN) / self.CYCLE_LEN
+
+        xmid = self.background_width / 2.0
+        ymid = self.background_height / 2.0
+        radius = min(xmid, ymid) / 2.0
+
+        r1 = Gdk.Rectangle()
+        r2 = Gdk.Rectangle()
+
+        i = 0
+        for pb in self.pixbufs:
+            i += 1
+            ang = 2.0 * math.pi * i / len(self.pixbufs) - f * 2.0 * math.pi
+
+            iw = pb.get_width()
+            ih = pb.get_height()
+
+            r = radius + (radius / 3.0) * math.sin(f * 2.0 * math.pi);
+
+            xpos = math.floor (xmid + r * math.cos(ang) - iw / 2.0 + 0.5)
+            ypos = math.floor (ymid + r * math.sin(ang) - ih / 2.0 + 0.5)
+
+            if i & 1:
+                k = math.sin(f * 2.0 * math.pi)
+            else:
+                k = math.cos(f * 2.0 * math.pi)
+
+            k = 2.0 * k * k
+            k = max(0.25, k)
+
+            r1.x = xpos
+            r1.y = ypos
+            r1.width = iw * k
+            r1.height = ih * k
+
+            r2.x = 0
+            r2.y = 0
+            r2.width = self.background_width
+            r2.height = self.background_height
+
+            success, dest = Gdk.rectangle_intersect(r1, r2)
+            if success:
+                alpha = 0
+                if i & 1:
+                    alpha = max(127, math.fabs(255 * math.sin(f * 2.0 * math.pi)))
+                else:
+                    alpha = max(127, math.fabs(255 * math.cos(f * 2.0 * math.pi)))
+
+                pb.composite(self.frame,
+                             dest.x, dest.y,
+                             dest.width, dest.height,
+                             xpos, ypos,
+                             k, k,
+                             GdkPixbuf.InterpType.NEAREST,
+                             alpha)
+
+        self.da.queue_draw()
+
+        self.frame_num += 1
+        return True
+
+    def cleanup_cb(self, widget):
+        GObject.source_remove(self.timeout_id)
+        Gtk.main_quit()
+            
+def main(demoapp=None):
+    app = PixbufApp()
+    Gtk.main()
+
+if __name__ == '__main__':
+    main()