dg2d.point source code

1 /**
2   Scalar and integer 2D point types.
3 
4   Copyright: Chris Jones
5   License: Boost Software License, Version 1.0
6   Authors: Chris Jones
7 */
8 
9 module dg2d.point;
10 
11 import dg2d.scalar;
12 
13 import std.algorithm: among;
14 
15 /**
16   Integer 2D point.
17   
18   This is typically used for specifying exact pixel coordinates.
19 */
20 
21 struct IPoint
22 {
23     int x = 0;
24     int y = 0;
25 
26     /** Constructs a IPoint with the spefcified coordinates */
27 
28     this(int x, int y)
29     {
30         this.x = x;
31         this.y = y;
32     }
33 
34     /** Constructs a IPoint with the spefcified coordinates */
35 
36     this(int[2] coords)
37     {
38         this.x = coords[0];
39         this.y = coords[1];
40     }
41 
42     /** returns true if x and y are both zero */
43 
44     bool isZero()
45     {
46         return ((x == 0) && (y == 0));
47     }
48 }
49 
50 /**
51   2D Point.
52 
53   Floating point 2D point.
54 */
55 
56 struct Point
57 {
58     Scalar x = 0;
59     Scalar y = 0;
60 
61     /** Constructs a Point with the spefcified coordinates */
62 
63     this(Scalar x, Scalar y)
64     {
65         this.x = x;
66         this.y = y;
67     }
68 
69     /** Constructs a Point with the spefcified coordinates */
70 
71     this(Scalar[2] coords)
72     {
73         this.x = coords[0];
74         this.y = coords[1];
75     }
76 
77     /** returns true if x and y are both zero */
78 
79     bool isZero()
80     {
81         return ((x == 0) && (y == 0));
82     }
83 
84     /** operator overload for add, subtract or multiply. */
85 
86     Point opBinary(string op)(Point rhs)
87         if (op.among!("+", "-", "*"))
88     {
89         mixin("return Point(x "~op~" rhs.x, y "~op~"rhs.y);");
90     }
91 
92     /** operator overload for add, subtract or multiply. */
93 
94     Point opBinary(string op, T)(T rhs)
95         if (op.among!("+", "-", "*") && canConvertToScalar(T))
96     {
97         mixin("return Point(x "~op~" rhs, y "~op~"rhs);");
98     }
99 
100     /** operator overload for add, subtract or multiply. */
101 
102     Point opBinary(string op, T)(T[2] rhs)
103         if (op.among!("+", "-", "*") && canConvertToScalar(T))
104     {
105         mixin("return Point(x "~op~" rhs[0], y "~op~"rhs[1]);");
106     }
107 }
108 
109 /** Returns point offset by offset_x,offset_y */
110 
111 Point offset(Point point, Scalar offset_x, Scalar offset_y)
112 {
113     return Point(point.x+offset_x, point.y+offset_y);
114 }
115 
116 /** Returns point scaled by scale_x,scale_y */
117 
118 Point scale(Point point, Scalar scale_x, Scalar scale_y)
119 {
120     return Point(point.x*scale_x, point.y*scale_y);
121 }
122 
123 /** Returns point scaled by scale_x,scale_y but relative to focus_x,focus_y */
124 
125 Point scale(Point point, Scalar scale_x, Scalar scale_y, Scalar focus_x, Scalar focus_y)
126 {
127     return Point((point.x-focus_x)*scale_x+focus_x, (point.y-focus_y)*scale_y+focus_y);
128 }
129 
130 // TODO - versions that take that pass in sin/cos values rather than call math funcs each time
131 // as they are very slow
132 
133 /** Returns point rotated by the specified angle. angle is in degrees [0..360] */
134 
135 Point rotate(Point point, Scalar angle) 
136 {
137     import std.math;
138 
139     Scalar sina = cast(Scalar) sin(angle*2*PI/360);
140     Scalar cosa = cast(Scalar) cos(angle*2*PI/360);
141     return Point(point.x*cosa-point.y*sina, point.x*sina+point.y*cosa);
142 }
143 
144 /** Returns point rotated by the specified angle around focus_x,focus_y. Angle
145 is in degrees [0..360] */
146 
147 Point rotate(Point point, Scalar angle, Scalar focus_x, Scalar focus_y)
148 {
149     import std.math;
150 
151     Scalar sina = cast(Scalar) sin(angle*2*PI/360);
152     Scalar cosa = cast(Scalar) cos(angle*2*PI/360);
153     return Point(
154         (point.x-focus_x)*cosa-(point.y-focus_y)*sina+focus_x,
155         (point.x-focus_x)*sina+(point.y-focus_y)*cosa+focus_y
156         );
157 }
158 
159