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

sky/tests/resources/display_list.dart

 
 import 'dart:async';
 import 'dart:sky' as sky;
 import "dart:sky.internals" as internals;
 import 'dart:typed_data';
 
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/object.dart';
 
@@ skipping 93 matching lines @@
   void drawImage(sky.Image image, Point p, Paint paint) {
     log("drawImage($image, $p, $paint)");
   }
 
   void drawImageRect(sky.Image image, sky.Rect src, sky.Rect dst, Paint paint) {
     log("drawImageRect($image, $src, $dst, paint)");
   }
 
   void paintChild(RenderObject child, Point position) {
     log("paintChild ${child.runtimeType} at $position");
-    child.paint(new TestRenderCanvas(new sky.PictureRecorder(), size, logger, indent: "$indent  |"));
+    child.paint(new TestRenderCanvas(new sky.PictureRecorder(), size, logger, indent: "$indent  |"), position.toOffset());
   }
 }
 
 class TestRenderView extends RenderView {
 
   TestRenderView([ RenderBox child = null ]) : super(child: child) {
     print("TestRenderView enabled");
     attach();
     rootConstraints = new ViewConstraints(size: new Size(800.0, 600.0)); // arbitrary figures
     scheduleInitialLayout();
     syncCheckFrame();
   }
 
   int frame = 0;
 
   String lastPaint = '';
   void log(String s) {
     lastPaint += "\n$s";
   }
 
   void paintFrame() {
     RenderObject.debugDoingPaint = true;
     frame += 1;
     lastPaint = '';
     log("PAINT FOR FRAME #${frame} ----------------------------------------------");
     var recorder = new sky.PictureRecorder();
     var canvas = new TestRenderCanvas(recorder, rootConstraints.size, log, indent: "${frame} |");
-    paint(canvas);
+    paint(canvas, Offset.zero);
     recorder.endRecording();
     log("------------------------------------------------------------------------");
     RenderObject.debugDoingPaint = false;
   }
 
   // TEST API:
 
   void syncCheckFrame() {
     RenderObject.flushLayout();
     paintFrame();
@@ skipping 25 matching lines @@
 
   Future test(Function builder) {
     runApp(new TestApp(builder: builder), renderViewOverride: renderView);
     return renderView.checkFrame();
   }
 
   void endTest() {
     renderView.endTest();
   }
 }