WIP Flexbox Layout Manager for Sky framework.

sky/examples/raw/simple_render_tree.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:math';
 import 'dart:sky';
 import 'package:sky/framework/layout2.dart';
 
 class RenderSolidColor extends RenderDecoratedBox {
   final int backgroundColor;
 
   RenderSolidColor(int backgroundColor)
       : super(new BoxDecoration(backgroundColor: backgroundColor)),
         backgroundColor = backgroundColor;
 
-  BoxDimensions getIntrinsicDimensions(BoxConstraints constraints) {
-    return new BoxDimensions.withConstraints(constraints, height: 200.0);
-  }
-
-  void layout(BoxConstraints constraints, { RenderNode relayoutSubtreeRoot }) {
-    width = constraints.constrainWidth(constraints.maxWidth);
-    height = constraints.constrainHeight(200.0);
-    layoutDone();
-  }
-
   bool handlePointer(PointerEvent event, { double x: 0.0, double y: 0.0 }) {
     if (event.type == 'pointerdown') {
       setBoxDecoration(new BoxDecoration(backgroundColor: 0xFFFF0000));
       return true;
     }
 
     if (event.type == 'pointerup') {
       setBoxDecoration(new BoxDecoration(backgroundColor: backgroundColor));
       return true;
     }
 
     return false;
   }
 }
 
+class RenderSolidColorBlock extends RenderSolidColor {
+  final double desiredHeight;
+
+  RenderSolidColorBlock(int backgroundColor, { double desiredHeight : 100.0 })
+      : super(backgroundColor), desiredHeight = desiredHeight;
+
+  BoxDimensions getIntrinsicDimensions(BoxConstraints constraints) {
+    return new BoxDimensions.withConstraints(constraints, height: requestedHeight);
+  }
+
+  void layout(BoxConstraints constraints, { RenderNode relayoutSubtreeRoot }) {
+    width = constraints.constrainWidth(constraints.maxWidth);
+    height = constraints.constrainHeight(desiredHeight);
+    layoutDone();
+  }
+}
+
+class RenderSolidColorFlex extends RenderSolidColor {
+  RenderSolidColorFlex(int backgroundColor, flex)
+      : super(backgroundColor) {
+    parentData = new FlexBoxParentData();
+    parentData.flex = flex;
+  }
+
+  void layout(BoxConstraints constraints, { RenderNode relayoutSubtreeRoot }) {
+    width = constraints.constrainWidth(constraints.maxWidth);
+    height = constraints.constrainHeight(constraints.maxHeight);
+    layoutDone();
+  }
+}
+
 RenderView renderView;
 
 void beginFrame(double timeStamp) {
   RenderNode.flushLayout();
 
   renderView.paintFrame();
 }
 
 bool handleEvent(Event event) {
   if (event is! PointerEvent)
     return false;
   return renderView.handlePointer(event, x: event.x, y: event.y);
 }
 
 void main() {
   view.setEventCallback(handleEvent);
   view.setBeginFrameCallback(beginFrame);
 
-  var root = new RenderBlock(
-      decoration: new BoxDecoration(backgroundColor: 0xFF00FFFF),
+  var root = new RenderFlex(
+      direction: FlexDirection.Column,
+      decoration: new BoxDecoration(backgroundColor: 0xFFFFFFFF));
+
+  var block = new RenderBlock(
+      decoration: new BoxDecoration(backgroundColor: 0x77000000),
       padding: const EdgeDims(10.0, 10.0, 10.0, 10.0));
+  block.add(new RenderSolidColorBlock(0xFF00FF00));
+  block.add(new RenderSolidColorBlock(0x3300FFFF));
 
-  root.add(new RenderSolidColor(0xFF00FF00));
-  root.add(new RenderSolidColor(0xFF0000FF));
+  root.add(new RenderSolidColorFlex(0xFFFFFF00, 1));
+  root.add(block);
+  root.add(new RenderSolidColorFlex(0xFF0000FF, 1));
+  root.add(new RenderSolidColorFlex(0x77FF00FF, 2));
 
   renderView = new RenderView(root: root);
   renderView.layout(newWidth: view.width, newHeight: view.height);
 
   view.scheduleFrame();
 }