Implement a stage view

examples/scene/scene.py

@@ -7,26 +7,20 @@ import gtk
 
 from sugar.scene.Stage import Stage
 from sugar.scene.Group import Group
+from sugar.scene.View import View
 from sugar.scene.PixbufActor import PixbufActor
 from sugar.scene.CircleLayout import CircleLayout
 from sugar.scene.Timeline import Timeline
 
-def __drawing_area_expose_cb(widget, event, stage):
-	stage.render(widget.window)
-
 def __next_frame_cb(timeline, frame_num, group):
 	angle = math.pi * 2 * frame_num / timeline.get_n_frames()
 	group.get_layout().set_angle(angle)
 	group.do_layout()
 
-	drawing_area.window.invalidate_rect(None, False)
-
 def __completed_cb(timeline, group):
 	group.get_layout().set_angle(0)
 	group.do_layout()
 
-	drawing_area.window.invalidate_rect(None, False)
-
 stage = Stage()
 
 pixbuf = gtk.gdk.pixbuf_new_from_file('background.png')
@@ -49,10 +43,9 @@ stage.add(icons_group)
 window = gtk.Window()
 window.set_default_size(640, 480)
 
-drawing_area = gtk.DrawingArea()
-drawing_area.connect('expose_event', __drawing_area_expose_cb, stage)
-window.add(drawing_area)
-drawing_area.show()
+view = View(stage)
+window.add(view)
+view.show()
 
 window.show()
 

sugar/scene/Actor.py

@@ -20,6 +20,7 @@ class Actor(gobject.GObject):
 	def set_position(self, x, y):
 		self._x = x
 		self._y = y
+		self.notify_changed()
 
 	def _get_parents(self):
 		parents = []
@@ -39,9 +40,16 @@ class Actor(gobject.GObject):
 				transf = actor._transf
 		return transf.get_position(x, y)
 
+	def notify_changed(self):
+		if self._parent:
+			self._parent.notify_changed()
+		else:
+			self.emit('changed')
+
 	def set_size(self, width, height):
 		self._width = width
 		self._height = height
+		self.notify_changed()
 
 	def render(self, drawable):
 		pass

sugar/scene/View.py

@@ -0,0 +1,21 @@
+import gtk
+
+from sugar.scene.Stage import Stage
+
+class View(gtk.DrawingArea):
+	def __init__(self, stage):
+		gtk.DrawingArea.__init__(self)
+
+		self._stage = stage
+		self._stage.connect('changed', self.__stage_changed_cb)
+		self.connect('expose_event', self.__expose_cb)
+
+	def __stage_changed_cb(self, stage):
+		if self.window:
+			self.window.invalidate_rect(None, False)
+
+	def __expose_cb(self, widget, event):
+		self._stage.render(widget.window)
+
+	def get_stage(self):
+		return self._stage