OLD | NEW |
| (Empty) |
1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file | |
2 // for details. All rights reserved. Use of this source code is governed by a | |
3 // BSD-style license that can be found in the LICENSE file. | |
4 part of dart.math; | |
5 | |
6 /** | |
7 * A utility class for representing two-dimensional positions. | |
8 */ | |
9 class Point<T extends num> { | |
10 final T x; | |
11 final T y; | |
12 | |
13 const Point([T x = 0, T y = 0]): this.x = x, this.y = y; | |
14 | |
15 String toString() => '($x, $y)'; | |
16 | |
17 bool operator ==(other) { | |
18 if (other is !Point) return false; | |
19 return x == other.x && y == other.y; | |
20 } | |
21 | |
22 int get hashCode => _JenkinsSmiHash.hash2(x.hashCode, y.hashCode); | |
23 | |
24 Point<T> operator +(Point<T> other) { | |
25 return new Point<T>(x + other.x, y + other.y); | |
26 } | |
27 | |
28 Point<T> operator -(Point<T> other) { | |
29 return new Point<T>(x - other.x, y - other.y); | |
30 } | |
31 | |
32 /** | |
33 * Scale this point by [factor] as if it were a vector. | |
34 * | |
35 * *Important* *Note*: This function accepts a `num` as its argument only so | |
36 * that you can scale Point<double> objects by an `int` factor. Because the | |
37 * star operator always returns the same type of Point that originally called | |
38 * it, passing in a double [factor] on a Point<int> _will_ _cause_ _a_ | |
39 * _runtime_ _error_ in checked mode. | |
40 */ | |
41 Point<T> operator *(num factor) { | |
42 return new Point<T>(x * factor, y * factor); | |
43 } | |
44 | |
45 /** | |
46 * Get the straight line (Euclidean) distance between the origin (0, 0) and | |
47 * this point. | |
48 */ | |
49 T get magnitude => sqrt(x * x + y * y); | |
50 | |
51 /** | |
52 * Returns the distance between `this` and [other]. | |
53 */ | |
54 double distanceTo(Point<T> other) { | |
55 var dx = x - other.x; | |
56 var dy = y - other.y; | |
57 return sqrt(dx * dx + dy * dy); | |
58 } | |
59 | |
60 /** | |
61 * Returns the squared distance between `this` and [other]. | |
62 * | |
63 * Squared distances can be used for comparisons when the actual value is not | |
64 * required. | |
65 */ | |
66 T squaredDistanceTo(Point<T> other) { | |
67 var dx = x - other.x; | |
68 var dy = y - other.y; | |
69 return dx * dx + dy * dy; | |
70 } | |
71 | |
72 Point<int> ceil() => new Point<int>(x.ceil(), y.ceil()); | |
73 Point<int> floor() => new Point<int>(x.floor(), y.floor()); | |
74 Point<int> round() => new Point<int>(x.round(), y.round()); | |
75 | |
76 /** | |
77 * Truncates x and y to integers and returns the result as a new point. | |
78 */ | |
79 Point<int> truncate() => new Point<int>(x.toInt(), y.toInt()); | |
80 } | |
OLD | NEW |