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 // 17 // Stroke math 18 // 19 //---------------------------------------------------------------------------- 20 #ifndef AGG_STROKE_MATH_INCLUDED 21 #define AGG_STROKE_MATH_INCLUDED 22 #include "agg_math.h" 23 #include "agg_vertex_sequence.h" 24 namespace agg 25 { 26 enum line_cap_e { 27 butt_cap, 28 square_cap, 29 round_cap 30 }; 31 enum line_join_e { 32 miter_join = 0, 33 miter_join_revert = 1, 34 miter_join_round = 4, 35 round_join = 2, 36 bevel_join = 3 37 }; 38 enum inner_join_e { 39 inner_bevel, 40 inner_miter, 41 inner_jag, 42 inner_round 43 }; 44 const FX_FLOAT stroke_theta = 1.0f / 1000.0f; 45 template<class VertexConsumer> 46 void stroke_calc_arc(VertexConsumer& out_vertices, 47 FX_FLOAT x, FX_FLOAT y, 48 FX_FLOAT dx1, FX_FLOAT dy1, 49 FX_FLOAT dx2, FX_FLOAT dy2, 50 FX_FLOAT width, 51 FX_FLOAT approximation_scale) 52 { 53 typedef typename VertexConsumer::value_type coord_type; 54 FX_FLOAT a1 = FXSYS_atan2(dy1, dx1); 55 FX_FLOAT a2 = FXSYS_atan2(dy2, dx2); 56 FX_FLOAT da = a1 - a2; 57 bool ccw = da > 0 && da < FX_PI; 58 if(width < 0) { 59 width = -width; 60 } 61 da = FXSYS_acos(width / (width + ((1.0f / 8) / approximation_scale))) * 2; 62 out_vertices.add(coord_type(x + dx1, y + dy1)); 63 if (da > 0) { 64 if (!ccw) { 65 if (a1 > a2) { 66 a2 += 2 * FX_PI; 67 } 68 a2 -= da / 4; 69 a1 += da; 70 while (a1 < a2) { 71 out_vertices.add(coord_type(x + (width * FXSYS_cos(a1)), 72 y + (width * FXSYS_sin(a1)))); 73 a1 += da; 74 } 75 } else { 76 if (a1 < a2) { 77 a2 -= 2 * FX_PI; 78 } 79 a2 += da / 4; 80 a1 -= da; 81 while (a1 > a2) { 82 out_vertices.add(coord_type(x + (width * FXSYS_cos(a1)), 83 y + (width * FXSYS_sin(a1)))); 84 a1 -= da; 85 } 86 } 87 } 88 out_vertices.add(coord_type(x + dx2, y + dy2)); 89 } 90 template<class VertexConsumer> 91 void stroke_calc_miter(VertexConsumer& out_vertices, 92 const vertex_dist& v0, 93 const vertex_dist& v1, 94 const vertex_dist& v2, 95 FX_FLOAT dx1, FX_FLOAT dy1, 96 FX_FLOAT dx2, FX_FLOAT dy2, 97 FX_FLOAT width, 98 line_join_e line_join, 99 FX_FLOAT miter_limit, 100 FX_FLOAT approximation_scale) 101 { 102 typedef typename VertexConsumer::value_type coord_type; 103 FX_FLOAT xi = v1.x; 104 FX_FLOAT yi = v1.y; 105 bool miter_limit_exceeded = true; 106 if(calc_intersection(v0.x + dx1, v0.y - dy1, 107 v1.x + dx1, v1.y - dy1, 108 v1.x + dx2, v1.y - dy2, 109 v2.x + dx2, v2.y - dy2, 110 &xi, &yi)) { 111 FX_FLOAT d1 = calc_distance(v1.x, v1.y, xi, yi); 112 FX_FLOAT lim = width * miter_limit; 113 if(d1 <= lim) { 114 out_vertices.add(coord_type(xi, yi)); 115 miter_limit_exceeded = false; 116 } 117 } else { 118 FX_FLOAT x2 = v1.x + dx1; 119 FX_FLOAT y2 = v1.y - dy1; 120 if ((((x2 - v0.x) * dy1) - ((v0.y - y2) * dx1) < 0) != 121 (((x2 - v2.x) * dy1) - ((v2.y - y2) * dx1) < 0)) { 122 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 123 miter_limit_exceeded = false; 124 } 125 } 126 if(miter_limit_exceeded) { 127 switch(line_join) { 128 case miter_join_revert: 129 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 130 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 131 break; 132 case miter_join_round: 133 stroke_calc_arc(out_vertices, 134 v1.x, v1.y, dx1, -dy1, dx2, -dy2, 135 width, approximation_scale); 136 break; 137 default: 138 out_vertices.add(coord_type(v1.x + dx1 + (dy1 * miter_limit), 139 v1.y - dy1 + (dx1 * miter_limit))); 140 out_vertices.add(coord_type(v1.x + dx2 - (dy2 * miter_limit), 141 v1.y - dy2 - (dx2 * miter_limit))); 142 break; 143 } 144 } 145 } 146 template<class VertexConsumer> 147 void stroke_calc_cap(VertexConsumer& out_vertices, 148 const vertex_dist& v0, 149 const vertex_dist& v1, 150 FX_FLOAT len, 151 line_cap_e line_cap, 152 FX_FLOAT width, 153 FX_FLOAT approximation_scale) 154 { 155 typedef typename VertexConsumer::value_type coord_type; 156 out_vertices.remove_all(); 157 FX_FLOAT dx1 = (v1.y - v0.y) / len; 158 FX_FLOAT dy1 = (v1.x - v0.x) / len; 159 FX_FLOAT dx2 = 0; 160 FX_FLOAT dy2 = 0; 161 dx1 = dx1 * width; 162 dy1 = dy1 * width; 163 if(line_cap != round_cap) { 164 if(line_cap == square_cap) { 165 dx2 = dy1; 166 dy2 = dx1; 167 } 168 out_vertices.add(coord_type(v0.x - dx1 - dx2, v0.y + dy1 - dy2)); 169 out_vertices.add(coord_type(v0.x + dx1 - dx2, v0.y - dy1 - dy2)); 170 } else { 171 FX_FLOAT a1 = FXSYS_atan2(dy1, -dx1); 172 FX_FLOAT a2 = a1 + FX_PI; 173 FX_FLOAT da = 174 FXSYS_acos(width / (width + ((1.0f / 8) / approximation_scale))) * 175 2; 176 out_vertices.add(coord_type(v0.x - dx1, v0.y + dy1)); 177 a1 += da; 178 a2 -= da / 4; 179 while(a1 < a2) { 180 out_vertices.add(coord_type(v0.x + (width * FXSYS_cos(a1)), 181 v0.y + (width * FXSYS_sin(a1)))); 182 a1 += da; 183 } 184 out_vertices.add(coord_type(v0.x + dx1, v0.y - dy1)); 185 } 186 } 187 template<class VertexConsumer> 188 void stroke_calc_join(VertexConsumer& out_vertices, 189 const vertex_dist& v0, 190 const vertex_dist& v1, 191 const vertex_dist& v2, 192 FX_FLOAT len1, 193 FX_FLOAT len2, 194 FX_FLOAT width, 195 line_join_e line_join, 196 inner_join_e inner_join, 197 FX_FLOAT miter_limit, 198 FX_FLOAT inner_miter_limit, 199 FX_FLOAT approximation_scale) 200 { 201 typedef typename VertexConsumer::value_type coord_type; 202 FX_FLOAT dx1, dy1, dx2, dy2; 203 dx1 = width * (v1.y - v0.y) / len1; 204 dy1 = width * (v1.x - v0.x) / len1; 205 dx2 = width * (v2.y - v1.y) / len2; 206 dy2 = width * (v2.x - v1.x) / len2; 207 out_vertices.remove_all(); 208 if(calc_point_location(v0.x, v0.y, v1.x, v1.y, v2.x, v2.y) > 0) { 209 switch(inner_join) { 210 default: 211 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 212 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 213 break; 214 case inner_miter: 215 stroke_calc_miter(out_vertices, 216 v0, v1, v2, dx1, dy1, dx2, dy2, 217 width, 218 miter_join_revert, 219 inner_miter_limit, 220 1.0f); 221 break; 222 case inner_jag: 223 case inner_round: { 224 FX_FLOAT d = (dx1 - dx2) * (dx1 - dx2) + (dy1 - dy2) * (dy1 - dy2); 225 if(d < len1 * len1 && d < len2 * len2) { 226 stroke_calc_miter(out_vertices, 227 v0, v1, v2, dx1, dy1, dx2, dy2, 228 width, 229 miter_join_revert, 230 inner_miter_limit, 231 1.0f); 232 } else { 233 if(inner_join == inner_jag) { 234 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 235 out_vertices.add(coord_type(v1.x, v1.y )); 236 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 237 } else { 238 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 239 out_vertices.add(coord_type(v1.x, v1.y )); 240 stroke_calc_arc(out_vertices, 241 v1.x, v1.y, dx2, -dy2, dx1, -dy1, 242 width, approximation_scale); 243 out_vertices.add(coord_type(v1.x, v1.y )); 244 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 245 } 246 } 247 } 248 break; 249 } 250 } else { 251 switch(line_join) { 252 case miter_join: 253 case miter_join_revert: 254 case miter_join_round: 255 stroke_calc_miter(out_vertices, 256 v0, v1, v2, dx1, dy1, dx2, dy2, 257 width, 258 line_join, 259 miter_limit, 260 approximation_scale); 261 break; 262 case round_join: 263 stroke_calc_arc(out_vertices, 264 v1.x, v1.y, dx1, -dy1, dx2, -dy2, 265 width, approximation_scale); 266 break; 267 default: 268 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 269 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 270 break; 271 } 272 } 273 } 274 } 275 #endif 276
