libs.utils.geometry_calculators source code

1 module libs.utils.geometry_calculators;
2 
3 import std.math;
4 
5 import libs.utils.point;
6 
7 /// Calculates the area of given polygon
8 /// using the Shoelace formula.
9 double polygonArea(Point[] pts)
10 {
11     // Number of vertices of the polygon
12     const n = cast(int) pts.length;
13 
14     // Initialize area
15     double area = 0;
16     int j;
17 
18     for (int k = 0; k < n; k++)
19     {
20         j = (k + 1) % n;
21         area += pts[k].x * pts[j].y;
22         area -= pts[j].x * pts[k].y;
23     }
24 
25     area = abs(area) / 2;
26 
27     return area;
28 }
29 
30 /// Calculates the total perimeter of a given polygon
31 double polygonPerimeter(Point[] pts)
32 {
33     // Initialize perimeter
34     double perimeter = 0;
35 
36     // Number of vertices of the polygon
37     int n = cast(int) pts.length;
38 
39     Point p1, p2;
40 
41     for (int i = 0; i < (n - 1); i++)
42     {
43         p1 = pts[i];
44         p2 = pts[i + 1];
45         perimeter += distanceBetweenTwoPoints(p1, p2);
46     }
47 
48     return perimeter;
49 }
50 
51 /// Implementation of distance between 2 points.
52 double distanceBetweenTwoPoints(Point p1, Point p2)
53 {
54     float x1, y1, x2, y2;
55     x1 = p1.x;
56     y1 = p1.y;
57     x2 = p2.x;
58     y2 = p2.y;
59     return sqrt(pow((y2 - y1), 2) + pow((x2 - x1), 2));
60 }