Add operator==, hashCode, and toString for Rect and Point dart classes.

sky/engine/core/painting/Rect.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.
 
 part of dart.sky;
 
+/// Holds 4 floating-point coordinates for a rectangle.
 class Rect {
-  Float32List _value;
+  final Float32List _value = new Float32List(4);
   double get left => _value[0];
   double get top => _value[1];
   double get right => _value[2];
   double get bottom => _value[3];
 
-  Rect() : new Float32List(4);
+  Rect();
 
   Rect.fromPointAndSize(Point point, Size size) {
-    _value = new Float32List(4)
-        ..[0] = point.x
-        ..[1] = point.y
-        ..[2] = point.x + size.width
-        ..[3] = point.y + size.height;
+    _value[0] = point.x

[sethladd, 2015/05/28 17:27:37]

you may want to move this down to:

  ..[0] = point.x

to be consistent with setLTRB

[Matt Perry, 2015/05/28 17:29:44]

Yep! Thanks. Actually, it doesn't work the way it's written now. I think if you
write
  _value[0] = x .. [1] = y;
then the cascade operator is applying to _value[0] instead of _value.

+      ..[1] = point.y
+      ..[2] = point.x + size.width
+      ..[3] = point.y + size.height;
   }
 
   Rect.fromLTRB(double left, double top, double right, double bottom) {
-    _value = new Float32List(4)
-        ..[0] = left
-        ..[1] = top
-        ..[2] = right
-        ..[3] = bottom;
+    setLTRB(left, top, right, bottom);
   }
 
   Point get upperLeft => new Point(left, top);
   Point get lowerRight => new Point(right, bottom);
 
   Size get size => new Size(right - left, bottom - top);
 
   // Rects are inclusive of the top and left edges but exclusive of the bottom
   // right edges.
-  bool contains(Point point) => point.x >= left && point.x < right
-                             && point.y >= top && point.y < bottom;
+  bool contains(Point point) =>
+      point.x >= left && point.x < right && point.y >= top && point.y < bottom;
 
   void setLTRB(double left, double top, double right, double bottom) {
-    _value[0] = left
-        ..[1] = top
-        ..[2] = right
-        ..[3] = bottom;
+    _value
+      ..[0] = left
+      ..[1] = top
+      ..[2] = right
+      ..[3] = bottom;
   }
+
+  bool operator ==(other) {
+    if (!(other is Rect)) return false;
+    for (var i = 0; i < 4; ++i) {
+      if (_value[i] != other._value[i]) return false;
+    }
+    return true;
+  }
+  int get hashCode {
+    return _value.fold(373, (value, item) => (37 * value + item.hashCode));
+  }
+  String toString() => "Rect.LTRB($left, $top, $right, $bottom)";
 }