flutter/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:sky';
import 'package:sky/framework/app.dart';
import 'package:sky/framework/layout2.dart';

class RenderSolidColor extends RenderDecoratedBox {
  final Size desiredSize;
  final int backgroundColor;

  RenderSolidColor(int backgroundColor, { this.desiredSize: const sky.Size.infinite() })
      : backgroundColor = backgroundColor,
        super(new BoxDecoration(backgroundColor: backgroundColor)) {
  }

  BoxDimensions getIntrinsicDimensions(BoxConstraints constraints) {
    return new BoxDimensions.withConstraints(constraints,
                                             width: desiredSize.width,
                                             height: desiredSize.height);
  }

  void performLayout() {
    size = constraints.constrain(desiredSize);
  }

  void handlePointer(PointerEvent event) {
    if (event.type == 'pointerdown')
      decoration = new BoxDecoration(backgroundColor: 0xFFFF0000);
    else if (event.type == 'pointerup')
      decoration = new BoxDecoration(backgroundColor: backgroundColor);
  }
}

AppView app;

void main() {
  var root = new RenderFlex(
      direction: FlexDirection.Vertical,
      decoration: new BoxDecoration(backgroundColor: 0xFF000000));

  void addFlexChild(RenderFlex parent, int backgroundColor, { int flex: 0 }) {
    RenderNode child = new RenderSolidColor(backgroundColor);
    parent.add(child);
    child.parentData.flex = flex;
  }

  // Yellow bar at top
  addFlexChild(root, 0xFFFFFF00, flex: 1);

  // Turquoise box
  root.add(new RenderSolidColor(0x7700FFFF, desiredSize: new Size(100.0, 100.0)));

  // Green and cyan render block with padding
  var renderBlock = new RenderBlock(decoration: new BoxDecoration(backgroundColor: 0xFFFFFFFF));

  renderBlock.add(new RenderSolidColor(0xFF00FF00, desiredSize: new Size(100.0, 50.0)));
  renderBlock.add(new RenderSolidColor(0x7700FFFF, desiredSize: new Size(50.0, 100.0)));

  root.add(new RenderPadding(const EdgeDims(10.0, 10.0, 10.0, 10.0), renderBlock));

  var row = new RenderFlex(
    direction: FlexDirection.Horizontal,
    decoration: new BoxDecoration(backgroundColor: 0xFF333333));

  // Purple and blue cells
  addFlexChild(row, 0x77FF00FF, flex: 1);
  addFlexChild(row, 0xFF0000FF, flex: 2);

  root.add(row);
  row.parentData.flex = 3;

  app = new AppView(root);

}