Animate checkboxes

sky/sdk/lib/framework/widgets/wrappers.dart

 
 import 'package:vector_math/vector_math.dart';
 
 import '../rendering/block.dart';
 import '../rendering/box.dart';
 import '../rendering/flex.dart';
 import '../rendering/object.dart';
 import '../rendering/paragraph.dart';
 import '../rendering/stack.dart';
 import 'ui_node.dart';
@@ skipping 31 matching lines @@
 
   RenderDecoratedBox createNode() => new RenderDecoratedBox(decoration: decoration);
 
   void syncRenderObject(DecoratedBox old) {
     super.syncRenderObject(old);
     root.decoration = decoration;
   }
 
 }
 
-// TODO(jackson) need a mechanism for marking the RenderCustomPaint as needing paint
 class CustomPaint extends OneChildRenderObjectWrapper {
 
-  CustomPaint({ this.callback, UINode child, Object key })
+  CustomPaint({ this.callback, this.token, UINode child, Object key })
     : super(child: child, key: key);
 
   RenderCustomPaint get root { RenderCustomPaint result = super.root; return result; }
   final CustomPaintCallback callback;
+  final dynamic token;  // set this to be repainted automatically when the token changes
 
   RenderCustomPaint createNode() => new RenderCustomPaint(callback: callback);
 
   void syncRenderObject(CustomPaint old) {
     super.syncRenderObject(old);
+    if (old != null && old.token != token)
+      root.markNeedsPaint();
     root.callback = callback;
   }
 
   void remove() {
     root.callback = null;
     super.remove();
   }
 
 }
 
@@ skipping 290 matching lines @@
     root.src = src;
     root.requestedSize = size;
   }
 
   void insert(RenderObjectWrapper child, dynamic slot) {
     assert(false);
     // Image does not support having children currently
   }
 
 }