1 2 //---------------------------------------------------------------------------- 3 // Anti-Grain Geometry - Version 2.3 4 // Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com) 5 // 6 // Permission to copy, use, modify, sell and distribute this software 7 // is granted provided this copyright notice appears in all copies. 8 // This software is provided "as is" without express or implied 9 // warranty, and with no claim as to its suitability for any purpose. 10 // 11 //---------------------------------------------------------------------------- 12 // Contact: mcseem (at) antigrain.com 13 // mcseemagg (at) yahoo.com 14 // http://www.antigrain.com 15 //---------------------------------------------------------------------------- 16 // Bessel function (besj) was adapted for use in AGG library by Andy Wilk 17 // Contact: castor.vulgaris (at) gmail.com 18 //---------------------------------------------------------------------------- 19 #ifndef AGG_MATH_INCLUDED 20 #define AGG_MATH_INCLUDED 21 #include "agg_basics.h" 22 namespace agg 23 { 24 const float intersection_epsilon = 1.0e-30f; 25 AGG_INLINE float calc_point_location(float x1, float y1, 26 float x2, float y2, 27 float x, float y) 28 { 29 return ((x - x2) * (y2 - y1)) - ((y - y2) * (x2 - x1)); 30 } 31 AGG_INLINE float calc_distance(float x1, float y1, float x2, float y2) 32 { 33 float dx = x2 - x1; 34 float dy = y2 - y1; 35 return FXSYS_sqrt2(dx, dy); 36 } 37 AGG_INLINE float calc_line_point_distance(float x1, float y1, 38 float x2, float y2, 39 float x, float y) 40 { 41 float dx = x2 - x1; 42 float dy = y2 - y1; 43 float d = FXSYS_sqrt2(dx, dy); 44 if(d < intersection_epsilon) { 45 return calc_distance(x1, y1, x, y); 46 } 47 return ((x - x2) * dy / d) - ((y - y2) * dx / d); 48 } 49 AGG_INLINE bool calc_intersection(float ax, float ay, float bx, float by, 50 float cx, float cy, float dx, float dy, 51 float* x, float* y) 52 { 53 float num = ((ay - cy) * (dx - cx)) - ((ax - cx) * (dy - cy)); 54 float den = ((bx - ax) * (dy - cy)) - ((by - ay) * (dx - cx)); 55 if (fabs(den) < intersection_epsilon) { 56 return false; 57 } 58 *x = ax + ((bx - ax) * num / den); 59 *y = ay + ((by - ay) * num / den); 60 return true; 61 } 62 } 63 #endif 64
