QuadTree should segfault less frequently.
[ipdf/code.git] / src / bezier.h
1 #ifndef _BEZIER_H
2 #define _BEZIER_H
3
4 #include "real.h"
5 #include "rect.h"
6 namespace IPDF
7 {
8         extern int Factorial(int n);
9         extern int BinomialCoeff(int n, int k);
10         extern Real Bernstein(int k, int n, const Real & u);
11
12         /** A _quadratic_ bezier. **/
13         struct Bezier
14         {
15                 Real x0; Real y0;
16                 Real x1; Real y1;
17                 Real x2; Real y2;
18                 Bezier() = default; // Needed so we can fread/fwrite this struct... for now.
19                 Bezier(Real _x0, Real _y0, Real _x1, Real _y1, Real _x2, Real _y2) : x0(_x0), y0(_y0), x1(_x1), y1(_y1), x2(_x2), y2(_y2) {}
20                 std::string Str() const
21                 {
22                         std::stringstream s;
23                         s << "Bezier{" << Float(x0) << "," << Float(y0) << " -> " << Float(x1) << "," << Float(y1) << " -> " << Float(x2) << "," << Float(y2) << "}";
24                         return s.str();
25                 }
26                 Bezier(const Bezier & cpy, const Rect & t = Rect(0,0,1,1)) : x0(cpy.x0), y0(cpy.y0), x1(cpy.x1), y1(cpy.y1), x2(cpy.x2),y2(cpy.y2)
27                 {
28                         x0 *= t.w;
29                         y0 *= t.h;
30                         x1 *= t.w;
31                         y1 *= t.h;
32                         x2 *= t.w;
33                         y2 *= t.h;
34                         x0 += t.x;
35                         y0 += t.y;
36                         x1 += t.x;
37                         y1 += t.y;
38                         x2 += t.x;
39                         y2 += t.y;
40                 }
41
42                 Rect ToRect() {return Rect(x0,y0,x2-x0,y2-y0);}
43
44                 /** Evaluate the Bezier at parametric parameter u, puts resultant point in (x,y) **/
45                 void Evaluate(Real & x, Real & y, const Real & u)
46                 {
47                         Real coeff[3];
48                         for (unsigned i = 0; i < 3; ++i)
49                                 coeff[i] = Bernstein(i,2,u);
50                         x = x0*coeff[0] + x1*coeff[1] + x2*coeff[2];
51                         y = y0*coeff[0] + y1*coeff[1] + y2*coeff[2];
52                 }
53
54         };
55
56
57
58 }
59
60 #endif //_BEZIER_H

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