--- a/icanvas.d	Sat Jul 11 22:49:41 2009 +0930
+++ b/icanvas.d	Sat Jul 11 23:32:22 2009 +0930
@@ -9,10 +9,13 @@
     void rel_pan(Vector screen_displacement);
     //void damage(Rectangle area);
 
+    double zoom() const;
     Point model_to_screen(Point model) const;
     Point screen_to_model(Point screen) const;
     Vector model_to_screen(Vector model) const;
     Vector screen_to_model(Vector screen) const;
+    Rectangle model_to_screen(Rectangle model) const;
+    Rectangle screen_to_model(Rectangle model) const;
     double model_to_screen(double model) const;
     double screen_to_model(double screen) const;
 }
@@ -32,5 +35,7 @@
 }
 
 abstract class Layer {
+    Rectangle bounds() const;
+    //void zoom_changed
     void draw(const Viewport viewport, in Rectangle damage, Context cr) const;
 }