Replace "expose-event" signal by a new "draw" signal

GtkWidget "expose-event" signal has been replaced by
a new "draw" signal [1]. The context is already
clipped [2], so do not base it on the values returned by
get_allocation like before.

[1] http://developer.gnome.org/gtk3/3.0/ch25s02.html#id1467092
[2] http://developer.gnome.org/gtk3/3.0/GtkWidget.html#GtkWidget-draw

Signed-off-by: Simon Schampijer <simon@schampijer.de>
[squashed with a patch by Benjamin Berg <benjamin@sipsolutions.net>;
 removed useless additions]
Signed-off-by: Sascha Silbe <silbe@activitycentral.com>

src/sugar3/graphics/alert.py

@@ -351,10 +351,9 @@ class _TimeoutIcon(Gtk.Alignment):
         self._text.set_attributes(attrlist)
         self.add(self._text)
         self._text.show()
-        self.connect("expose_event", self.__expose_cb)
+        self.connect('draw', self.__draw_cb)
 
-    def __expose_cb(self, widget, event):
-        context = widget.get_window().cairo_create()
+    def __draw_cb(self, widget, context):
         self._draw(context)
         return False
 
@@ -364,13 +363,15 @@ class _TimeoutIcon(Gtk.Alignment):
         self._text.size_request()
 
     def _draw(self, context):
-        rect = self.get_allocation()
-        x = rect.x + rect.width * 0.5
-        y = rect.y + rect.height * 0.5
-        radius = rect.width / 2
+        w = self.get_allocated_width()
+        h = self.get_allocated_height()
+        x = w * 0.5
+        y = h * 0.5
+        radius = w / 2
         context.arc(x, y, radius, 0, 2 * math.pi)
         widget_style = self.get_style()
-        context.set_source_color(widget_style.bg[self.get_state()])
+        color = widget_style.bg[self.get_state()]
+        context.set_source_rgb(color.red, color.green, color.blue)
         context.fill_preserve()
 
     def set_text(self, text):

src/sugar3/graphics/icon.py

@@ -385,7 +385,7 @@ class Icon(Gtk.Image):
             width = 0
         return (width, width)
 
-    def do_expose_event(self, event):
+    def do_draw(self, cr):
         """
         Parameters
         ----------
@@ -414,8 +414,6 @@ class Icon(Gtk.Image):
         y = math.floor(ypad +
             (allocation.height - requisition.height) * yalign)
 
-        cr = self.get_window().cairo_create()
-
         if self._scale != 1.0:
             cr.scale(self._scale, self._scale)