--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doodle/dia/layer_stack.d	Sun Aug 15 01:11:58 2010 +0930
@@ -0,0 +1,30 @@
+module doodle.dia.layer_stack;
+
+public {
+    import doodle.dia.icanvas;
+}
+
+final class LayerStack {
+    this(in Layer[] layers) {
+        _layers = layers.dup;
+    }
+
+    Rectangle bounds() const {
+        // Take the union of all layer bounds
+        Rectangle bounds = Rectangle.DEFAULT;
+        foreach (layer; _layers) { bounds = bounds | layer.bounds; }
+        assert(bounds.valid);
+        return bounds;
+    }
+
+    void draw(in Rectangle pixelDamage, scope Context pixelCr,
+              in Rectangle modelDamage, scope Context modelCr) {
+        foreach(layer; _layers) {
+            layer.draw(pixelDamage, pixelCr, modelDamage, modelCr);
+        }
+    }
+
+    private {
+        Layer[] _layers;
+    }
+}