| // 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, T y) |

| : this.x = x, |

| this.y = y; |

| |

| String toString() => 'Point($x, $y)'; |

| |

| /** |

| * A `Point` is only equal to another `Point` with the same coordinates. |

| * |

| * This point is equal to `other` if, and only if, |

| * `other` is a `Point` with |

| * [x] equal to `other.x` and [y] equal to `other.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 were 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 /*T|int*/ factor) { |

| return new Point<T>( |

| (x * factor) as dynamic/*=T*/, (y * factor) as dynamic/*=T*/); |

| } |

| |

| /** |

| * 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; |

| } |

| } |