Flesh out Rect/Point/Size classes in dart:sky

R=mpcomplete@chromium.org

Review URL: https://codereview.chromium.org/1152213003

engine/core/core.gni

@@ -1138,8 +1138,9 @@ core_idl_files = get_path_info([
                                "abspath")
 
 core_dart_files = get_path_info([
-                                  "painting/Rect.dart",
                                   "painting/Point.dart",
+                                  "painting/Rect.dart",
+                                  "painting/Size.dart",
                                 ],
                                 "abspath")
 

engine/core/painting/Point.dart

@@ -10,4 +10,3 @@ class Point {
 
   Point(this.x, this.y);
 }
-

engine/core/painting/Rect.dart

@@ -11,7 +11,38 @@ class Rect {
   double get right => _value[2];
   double get bottom => _value[3];
 
+  Rect() : new Float32List(4);
+
+  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;
+  }
+
+  Rect.fromLTRB(double left, double top, double right, double bottom) {
+    _value = new Float32List(4)
+        ..[0] = left
+        ..[1] = top
+        ..[2] = right
+        ..[3] = 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;
+
   void setLTRB(double left, double top, double right, double bottom) {
-    _value = new Float32List.fromList([left, top, right, bottom]);
+    _value[0] = left
+        ..[1] = top
+        ..[2] = right
+        ..[3] = bottom;
   }
 }

engine/core/painting/Size.dart

@@ -0,0 +1,12 @@
+// 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;
+
+class Size {
+  double width;
+  double height;
+
+  Point(this.width, this.height);
+}