Instead of applying a transform for every RenderObject, pass down an Offset for where to paint.

sky/sdk/lib/example/rendering/interactive_flex.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:sky';
 import 'dart:math' as math;
 
-import 'package:sky/mojo/net/image_cache.dart' as image_cache;
 import 'package:sky/painting/text_style.dart';
-import 'package:sky/rendering/block.dart';
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/flex.dart';
 import 'package:sky/rendering/object.dart';
 import 'package:sky/rendering/paragraph.dart';
 import 'package:sky/rendering/sky_binding.dart';
 
 import '../lib/solid_color_box.dart';
 
 class Touch {
   final double x;
@@ skipping 71 matching lines @@
   column.parentData.flex = 8;
 
   RenderDecoratedBox root = new RenderDecoratedBox(
     decoration: new BoxDecoration(backgroundColor: const Color(0xFFFFFFFF)),
     child: row
   );
 
   new SkyBinding(root: root);
   view.setEventCallback(handleEvent);
 }