| // 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 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 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; |
| } |
| } |