Port scaffold to fn3

packages/flutter/lib/src/fn3/scaffold.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' as sky;
+
+import 'package:sky/material.dart';
+import 'package:sky/rendering.dart';
+import 'package:sky/src/fn3/framework.dart';
+
+// Slots are painted in this order and hit tested in reverse of this order
+enum ScaffoldSlots {
+  body,
+  statusBar,
+  toolbar,
+  snackBar,
+  floatingActionButton,
+  drawer
+}
+
+class RenderScaffold extends RenderBox {
+
+  RenderScaffold({
+    RenderBox body,
+    RenderBox statusBar,
+    RenderBox toolbar,
+    RenderBox snackBar,
+    RenderBox floatingActionButton,
+    RenderBox drawer
+  }) {
+    this[ScaffoldSlots.body] = body;
+    this[ScaffoldSlots.statusBar] = statusBar;
+    this[ScaffoldSlots.toolbar] = toolbar;
+    this[ScaffoldSlots.snackBar] = snackBar;
+    this[ScaffoldSlots.floatingActionButton] = floatingActionButton;
+    this[ScaffoldSlots.drawer] = drawer;
+  }
+
+  Map<ScaffoldSlots, RenderBox> _slots = new Map<ScaffoldSlots, RenderBox>();
+  RenderBox operator[] (ScaffoldSlots slot) => _slots[slot];
+  void operator[]= (ScaffoldSlots slot, RenderBox value) {
+    RenderBox old = _slots[slot];
+    if (old == value)
+      return;
+    if (old != null)
+      dropChild(old);
+    if (value == null) {
+      _slots.remove(slot);
+    } else {
+      _slots[slot] = value;
+      adoptChild(value);
+    }
+    markNeedsLayout();
+  }
+
+  void attachChildren() {
+    for (ScaffoldSlots slot in ScaffoldSlots.values) {
+      RenderBox box = _slots[slot];
+      if (box != null)
+        box.attach();
+    }
+  }
+
+  void detachChildren() {
+    for (ScaffoldSlots slot in ScaffoldSlots.values) {
+      RenderBox box = _slots[slot];
+      if (box != null)
+        box.detach();
+    }
+  }
+
+  void visitChildren(RenderObjectVisitor visitor) {
+    for (ScaffoldSlots slot in ScaffoldSlots.values) {
+      RenderBox box = _slots[slot];
+      if (box != null)
+        visitor(box);
+    }
+  }
+
+  ScaffoldSlots remove(RenderBox child) {
+    assert(child != null);
+    for (ScaffoldSlots slot in ScaffoldSlots.values) {
+      if (_slots[slot] == child) {
+        this[slot] = null;
+        return slot;
+      }
+    }
+    return null;
+  }
+
+  bool get sizedByParent => true;
+  void performResize() {
+    size = constraints.biggest;
+    assert(!size.isInfinite);
+  }
+
+  // TODO(eseidel): These change based on device size!
+  // http://www.google.com/design/spec/layout/metrics-keylines.html#metrics-keylines-keylines-spacing
+  static const kButtonX = 16.0; // left from right edge of body
+  static const kButtonY = 16.0; // up from bottom edge of body
+
+  void performLayout() {
+    double bodyHeight = size.height;
+    double bodyPosition = 0.0;
+    if (_slots[ScaffoldSlots.statusBar] != null) {
+      RenderBox statusBar = _slots[ScaffoldSlots.statusBar];
+      statusBar.layout(new BoxConstraints.tight(new Size(size.width, kStatusBarHeight)));
+      assert(statusBar.parentData is BoxParentData);
+      statusBar.parentData.position = new Point(0.0, size.height - kStatusBarHeight);
+      bodyHeight -= kStatusBarHeight;
+    }
+    if (_slots[ScaffoldSlots.toolbar] != null) {
+      RenderBox toolbar = _slots[ScaffoldSlots.toolbar];
+      double toolbarHeight = kToolBarHeight + sky.view.paddingTop;
+      toolbar.layout(new BoxConstraints.tight(new Size(size.width, toolbarHeight)));
+      assert(toolbar.parentData is BoxParentData);
+      toolbar.parentData.position = Point.origin;
+      bodyPosition += toolbarHeight;
+      bodyHeight -= toolbarHeight;
+    }
+    if (_slots[ScaffoldSlots.body] != null) {
+      RenderBox body = _slots[ScaffoldSlots.body];
+      body.layout(new BoxConstraints.tight(new Size(size.width, bodyHeight)));
+      assert(body.parentData is BoxParentData);
+      body.parentData.position = new Point(0.0, bodyPosition);
+    }
+    if (_slots[ScaffoldSlots.snackBar] != null) {
+      RenderBox snackBar = _slots[ScaffoldSlots.snackBar];
+      // TODO(jackson): On tablet/desktop, minWidth = 288, maxWidth = 568
+      snackBar.layout(new BoxConstraints(minWidth: size.width, maxWidth: size.width, minHeight: 0.0, maxHeight: size.height),
+                      parentUsesSize: true);
+      assert(snackBar.parentData is BoxParentData);
+      // Position it off-screen. SnackBar slides in with an animation.
+      snackBar.parentData.position = new Point(0.0, size.height);
+    }
+    if (_slots[ScaffoldSlots.floatingActionButton] != null) {
+      RenderBox floatingActionButton = _slots[ScaffoldSlots.floatingActionButton];
+      Size area = new Size(size.width - kButtonX, size.height - kButtonY);
+      floatingActionButton.layout(new BoxConstraints.loose(area), parentUsesSize: true);
+      assert(floatingActionButton.parentData is BoxParentData);
+      floatingActionButton.parentData.position = (area - floatingActionButton.size).toPoint();
+    }
+    if (_slots[ScaffoldSlots.drawer] != null) {
+      RenderBox drawer = _slots[ScaffoldSlots.drawer];
+      drawer.layout(new BoxConstraints(minWidth: 0.0, maxWidth: size.width, minHeight: size.height, maxHeight: size.height));
+      assert(drawer.parentData is BoxParentData);
+      drawer.parentData.position = Point.origin;
+    }
+  }
+
+  void paint(PaintingContext context, Offset offset) {
+    for (ScaffoldSlots slot in ScaffoldSlots.values) {
+      RenderBox box = _slots[slot];
+      if (box != null) {
+        assert(box.parentData is BoxParentData);
+        context.paintChild(box, box.parentData.position + offset);
+      }
+    }
+  }
+
+  void hitTestChildren(HitTestResult result, { Point position }) {
+    for (ScaffoldSlots slot in ScaffoldSlots.values.reversed) {
+      RenderBox box = _slots[slot];
+      if (box != null) {
+        assert(box.parentData is BoxParentData);
+        if (box.hitTest(result, position: (position - box.parentData.position).toPoint()))
+          return;
+      }
+    }
+  }
+
+  String debugDescribeChildren(String prefix) {
+    return _slots.keys.map((slot) => '${prefix}${slot}: ${_slots[slot].toStringDeep(prefix)}').join();
+  }
+}
+
+class Scaffold extends RenderObjectWidget {
+  Scaffold({
+    Key key,
+    Widget body,
+    Widget statusBar,
+    Widget toolbar,
+    Widget snackBar,
+    Widget floatingActionButton,
+    Widget drawer
+  }) : super(key: key) {
+    _children[ScaffoldSlots.body] = body;
+    _children[ScaffoldSlots.statusBar] = statusBar;
+    _children[ScaffoldSlots.toolbar] = toolbar;
+    _children[ScaffoldSlots.snackBar] = snackBar;
+    _children[ScaffoldSlots.floatingActionButton] = floatingActionButton;
+    _children[ScaffoldSlots.drawer] = drawer;
+  }
+
+  final Map<ScaffoldSlots, Widget> _children = new Map<ScaffoldSlots, Widget>();
+
+  RenderScaffold createRenderObject() => new RenderScaffold();
+
+  ScaffoldElement createElement() => new ScaffoldElement(this);
+}
+
+class ScaffoldElement extends RenderObjectElement<Scaffold> {
+  ScaffoldElement(Scaffold widget) : super(widget);
+
+  Map<ScaffoldSlots, Element> _children;
+
+  RenderScaffold get renderObject => super.renderObject;
+
+  void visitChildren(ElementVisitor visitor) {
+    for (ScaffoldSlots slot in ScaffoldSlots.values) {
+      Element element = _children[slot];
+      if (element != null)
+        visitor(element);
+    }
+  }
+
+  void mount(Element parent, dynamic newSlot) {
+    super.mount(parent, newSlot);
+    _children = new Map<ScaffoldSlots, Element>();
+    for (ScaffoldSlots slot in ScaffoldSlots.values) {
+      _children[slot] = widget._children[slot].createElement()
+        ..mount(this, slot);
+    }
+  }
+
+  void update(Scaffold newWidget) {
+    super.update(newWidget);
+    assert(widget == newWidget);
+    for (ScaffoldSlots slot in ScaffoldSlots.values) {
+      _children[slot] = updateChild(_children[slot], widget._children[slot], slot);
+      assert((_children[slot] == null) == (widget._children[slot] == null));
+    }
+  }
+
+  void insertChildRenderObject(RenderObject child, ScaffoldSlots slot) {
+    renderObject[slot] = child;
+  }
+
+  void moveChildRenderObject(RenderObject child, dynamic slot) {
+    removeChildRenderObject(child);
+    insertChildRenderObject(child, slot);
+  }
+
+  void removeChildRenderObject(RenderObject child) {
+    assert(renderObject == child.parent);
+    renderObject.remove(child);
+  }
+}