libs/agg/agg_math.h

37     AGG_INLINE double cross_product(double x1, double y1,
41         return (x - x2) * (y2 - y1) - (y - y2) * (x2 - x1);
45     AGG_INLINE bool point_in_triangle(double x1, double y1,
50         bool cp1 = cross_product(x1, y1, x2, y2, x, y) < 0.0;
52         bool cp3 = cross_product(x3, y3, x1, y1, x, y) < 0.0;
57     AGG_INLINE double calc_distance(double x1, double y1, double x2, double y2)
60         double dy = y2-y1;
65     AGG_INLINE double calc_sq_distance(double x1, double y1, double x2, double y2)
68         double dy = y2-y1;
73     AGG_INLINE double calc_line_point_distance(double x1, double y1,
78         double dy = y2-y1;
82             return calc_distance(x1, y1, x, y);
88     AGG_INLINE double calc_segment_point_u(double x1, double y1,
93         double dy = y2 - y1;
101         double pdy = y - y1;
107     AGG_INLINE double calc_segment_point_sq_distance(double x1, double y1,
114 	        return calc_sq_distance(x, y, x1, y1);
121         return calc_sq_distance(x, y, x1 + u * (x2 - x1), y1 + u * (y2 - y1));
125     AGG_INLINE double calc_segment_point_sq_distance(double x1, double y1,
131                 x1, y1, x2, y2, x, y,
132                 calc_segment_point_u(x1, y1, x2, y2, x, y));
150     AGG_INLINE bool intersection_exists(double x1, double y1, double x2, double y2,
156         double dy1 = y2 - y1;
161                ((x1 - x4) * dy2 - (y1 - y4) * dx2 < 0.0) !=
167         //double den  = (x2-x1) * (y4-y3) - (y2-y1) * (x4-x3);
169         //double nom1 = (x4-x3) * (y1-y3) - (y4-y3) * (x1-x3);
170         //double nom2 = (x2-x1) * (y1-y3) - (y2-y1) * (x1-x3);
178                                     double x1, double y1,
183         double dy = y2 - y1;
190     AGG_INLINE void dilate_triangle(double x1, double y1,
202         double loc = cross_product(x1, y1, x2, y2, x3, y3);
205             if(cross_product(x1, y1, x2, y2, x3, y3) > 0.0)
209             calc_orthogonal(d, x1, y1, x2, y2, &dx1, &dy1);
211             calc_orthogonal(d, x3, y3, x1, y1, &dx3, &dy3);
213         *x++ = x1 + dx1;  *y++ = y1 + dy1;
218         *x++ = x1 + dx3;  *y++ = y1 + dy3;
222     AGG_INLINE double calc_triangle_area(double x1, double y1,
226         return (x1*y2 - x2*y1 + x2*y3 - x3*y2 + x3*y1 - x1*y3) * 0.5;