Move Rectangle and Point into dart:math.

sdk/lib/math/point.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. 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.math;
+
+/**
+ * A utility class for representing two-dimensional positions.
+ */
+class Point<T extends num> {
+  final T x;
+  final T y;
+
+  const Point([T x = 0, T y = 0]): this.x = x, this.y = y;
+
+  String toString() => 'Point($x, $y)';
+
+  bool operator ==(other) {
+    if (other is !Point) return false;
+    return x == other.x && y == other.y;
+  }
+
+  int get hashCode => _JenkinsSmiHash.hash2(x.hashCode, y.hashCode);
+
+  /**
+   * Add [other] to `this`, as if both points were vectors.
+   *
+   * Returns the resulting "vector" as a Point.
+   */
+  Point<T> operator +(Point<T> other) {
+    return new Point<T>(x + other.x, y + other.y);
+  }
+
+  /**
+   * Subtract [other] from `this`, as if both points were vectors.
+   *
+   * Returns the resulting "vector" as a Point.
+   */
+  Point<T> operator -(Point<T> other) {
+    return new Point<T>(x - other.x, y - other.y);
+  }
+
+  /**
+   * Scale this point by [factor] as if it was a vector.
+   *
+   * *Important* *Note*: This function accepts a `num` as its argument only so
+   * that you can scale Point<double> objects by an `int` factor. Because the
+   * star operator always returns the same type of Point that originally called
+   * it, passing in a double [factor] on a `Point<int>` _causes_ _a_
+   * _runtime_ _error_ in checked mode.
+   */
+  Point<T> operator *(num factor) {
+    return new Point<T>(x * factor, y * factor);
+  }
+
+  /**
+   * Get the straight line (Euclidean) distance between the origin (0, 0) and
+   * this point.
+   */
+  double get magnitude => sqrt(x * x + y * y);
+
+  /**
+   * Returns the distance between `this` and [other].
+   */
+  double distanceTo(Point<T> other) {
+    var dx = x - other.x;
+    var dy = y - other.y;
+    return sqrt(dx * dx + dy * dy);
+  }
+
+  /**
+   * Returns the squared distance between `this` and [other].
+   *
+   * Squared distances can be used for comparisons when the actual value is not
+   * required.
+   */
+  T squaredDistanceTo(Point<T> other) {
+    var dx = x - other.x;
+    var dy = y - other.y;
+    return dx * dx + dy * dy;
+  }
+}