Implement translation

sugar/scene/Actor.py

@@ -13,5 +13,5 @@ class Actor:
 		self._width = width
 		self._height = height
 
-	def render(self, window):
+	def render(self, window, transf):
 		pass

sugar/scene/Group.py

@@ -1,9 +1,15 @@
 from sugar.scene.Actor import Actor
+from sugar.scene.Transformation import Transformation
 
 class Group(Actor):
 	def __init__(self):
 		self._actors = []
 		self._layout = None
+		self._transf = Transformation()
+
+	def set_position(self, x, y):
+		Actor.set_position(self, x, y)
+		self._transf.set_translation(x, y)
 
 	def add(self, actor):
 		self._actors.append(actor)
@@ -27,6 +33,7 @@ class Group(Actor):
 		if self._layout:
 			self._layout.layout_group(self)
 
-	def render(self, drawable):
+	def render(self, drawable, transf):
+		transf = transf.compose(self._transf)
 		for actor in self._actors:
-			actor.render(drawable)
+			actor.render(drawable, transf)

sugar/scene/PixbufActor.py

@@ -8,6 +8,7 @@ class PixbufActor(Actor):
 
 		self._pixbuf = pixbuf
 
-	def render(self, drawable):
+	def render(self, drawable, transf):
+		(x, y) = transf.get_position(self._x, self._y)
 		gc = gtk.gdk.GC(drawable)
-		drawable.draw_pixbuf(gc, self._pixbuf, 0, 0, self._x, self._y)
+		drawable.draw_pixbuf(gc, self._pixbuf, 0, 0, x, y)

sugar/scene/Stage.py

@@ -1,4 +1,5 @@
 from sugar.scene.Group import Group
+from sugar.scene.Transformation import Transformation
 
 class Stage(Group):
 	def __init__(self):
@@ -7,3 +8,8 @@ class Stage(Group):
 
 	def get_fps(self):
 		return self._fps
+
+	def render(self, drawable, transf = None):
+		if transf == None:
+			transf = Transformation()
+		Group.render(self, drawable, transf)

sugar/scene/Transformation.py

@@ -0,0 +1,21 @@
+import copy
+
+class Transformation:
+	def __init__(self):
+		self._translation_x = 0
+		self._translation_y = 0
+
+	def set_translation(self, x, y):
+		self._translation_x = x
+		self._translation_y = y
+
+	def get_position(self, x, y):
+		translated_x = x + self._translation_x
+		translated_y = y + self._translation_y
+		return (translated_x, translated_y)
+
+	def compose(self, transf):
+		composed = copy.copy(transf)
+		composed._translation_x += transf._translation_x
+		composed._translation_y += transf._translation_y
+		return composed