composed components

lib/components/composed_component.dart

@@ -0,0 +1,59 @@
+
+import 'dart:ui';
+
+import 'package:flame/components/component.dart';
+import 'package:flame/components/resizable.dart';
+import 'package:ordered_set/comparing.dart';
+import 'package:ordered_set/ordered_set.dart';
+
+
+typedef IterateOverComponents = void Function(Component component);
+
+abstract class ComposedComponent extends Component {
+  OrderedSet<Component> components = new OrderedSet(Comparing.on((c) => c.priority()));
+
+  @override
+  render(Canvas canvas) {
+    canvas.save();
+    components.forEach((comp) => renderComponent(canvas, comp));
+    canvas.restore();
+  }
+
+  void renderComponent(Canvas canvas, Component c) {
+    c.render(canvas);
+    canvas.restore();
+    canvas.save();
+  }
+
+  @override
+  void update(double t) {
+    components.forEach((c) => c.update(t));
+    components.removeWhere((c) => c.destroy());
+  }
+
+  void add(Component c) {
+    this.components.add(c);
+
+    if(this is Resizable){
+      // first time resize
+      Resizable thisResizable = this as Resizable;
+      if (thisResizable.size != null) {
+        c.resize(thisResizable.size);
+      }
+    }
+  }
+
+  void iterateOverComponents ( IterateOverComponents iterateOverComponentsCallback ){
+    components.forEach(iterateOverComponentsCallback);
+  }
+
+  @override
+  void resize(Size size) {
+    if(this is Resizable){
+      Resizable thisResizable = this as Resizable;
+      thisResizable.size = size;
+      components.forEach((c) => c.resize(size));
+    }
+  }
+
+}