Support for FlexAlignItems.stretch.

sky/sdk/lib/rendering/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:math' as math;
 
 import 'box.dart';
 import 'object.dart';
 
 class FlexBoxParentData extends BoxParentData with ContainerParentDataMixin<RenderBox> {
@@ skipping 15 matching lines @@
   end,
   center,
   spaceBetween,
   spaceAround,
 }
 
 enum FlexAlignItems {
   start,
   end,
   center,
+  stretch,
 }
 
 typedef double _ChildSizingFunction(RenderBox child, BoxConstraints constraints);
 
 class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, FlexBoxParentData>,
                                         RenderBoxContainerDefaultsMixin<RenderBox, FlexBoxParentData> {
   // lays out RenderBox children using flexible layout
 
   RenderFlex({
     FlexDirection direction: FlexDirection.horizontal,
@@ skipping 229 matching lines @@
     double crossSize = 0.0;  // This will be determined after laying out the children
     double freeSpace = mainSize;
     RenderBox child = firstChild;
     while (child != null) {
       assert(child.parentData is FlexBoxParentData);
       totalChildren++;
       int flex = _getFlex(child);
       if (flex > 0) {
         totalFlex += child.parentData.flex;
       } else {
-        BoxConstraints innerConstraints = new BoxConstraints(maxHeight: constraints.maxHeight,
-                                                             maxWidth: constraints.maxWidth);
+        BoxConstraints innerConstraints;
+        if (alignItems == FlexAlignItems.stretch) {
+          switch (_direction) {
+            case FlexDirection.horizontal:
+              innerConstraints = new BoxConstraints(maxWidth: constraints.maxWidth,
+                                                    minHeight: constraints.minHeight,
+                                                    maxHeight: constraints.maxHeight);
+              break;
+            case FlexDirection.vertical:
+              innerConstraints = new BoxConstraints(minWidth: constraints.minWidth,
+                                                    maxWidth: constraints.maxWidth,
+                                                    maxHeight: constraints.maxHeight);
+              break;
+          }
+        } else {
+          innerConstraints = constraints.loosen();
+        }
         child.layout(innerConstraints, parentUsesSize: true);
         freeSpace -= _getMainSize(child);
         crossSize = math.max(crossSize, _getCrossSize(child));
       }
       child = child.parentData.nextSibling;
     }
 
     // Steps 4-5. Distribute remaining space to flexible children.
     double spacePerFlex = totalFlex > 0 ? (freeSpace / totalFlex) : 0.0;
     double usedSpace = 0.0;
@@ skipping 62 matching lines @@
         break;
     }
 
     // Position elements. For now, center the flex items in the cross direction
     double childMainPosition = leadingSpace;
     child = firstChild;
     while (child != null) {
       assert(child.parentData is FlexBoxParentData);
       double childCrossPosition;
       switch (_alignItems) {
+        case FlexAlignItems.stretch:
         case FlexAlignItems.start:
           childCrossPosition = 0.0;
           break;
         case FlexAlignItems.end:
           childCrossPosition = crossSize - _getCrossSize(child);
           break;
         case FlexAlignItems.center:
           childCrossPosition = crossSize / 2.0 - _getCrossSize(child) / 2.0;
           break;
       }
@@ skipping 11 matching lines @@
   }
 
   void hitTestChildren(HitTestResult result, { Point position }) {
     defaultHitTestChildren(result, position: position);
   }
 
   void paint(PaintingCanvas canvas, Offset offset) {
     defaultPaint(canvas, offset);
   }
 }