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 float stroke_theta = 1.0f / 1000.0f; 45 template<class VertexConsumer> 46 void stroke_calc_arc(VertexConsumer& out_vertices, 47 float x, float y, 48 float dx1, float dy1, 49 float dx2, float dy2, 50 float width, 51 float approximation_scale) 52 { 53 typedef typename VertexConsumer::value_type coord_type; 54 float a1 = atan2(dy1, dx1); 55 float a2 = atan2(dy2, dx2); 56 float da = a1 - a2; 57 bool ccw = da > 0 && da < FX_PI; 58 if(width < 0) { 59 width = -width; 60 } 61 da = 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( 72 coord_type(x + (width * cos(a1)), y + (width * 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( 83 coord_type(x + (width * cos(a1)), y + (width * 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 float dx1, float dy1, 96 float dx2, float dy2, 97 float width, 98 line_join_e line_join, 99 float miter_limit, 100 float approximation_scale) 101 { 102 typedef typename VertexConsumer::value_type coord_type; 103 float xi = v1.x; 104 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 float d1 = calc_distance(v1.x, v1.y, xi, yi); 112 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 float x2 = v1.x + dx1; 119 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 float len, 151 line_cap_e line_cap, 152 float width, 153 float approximation_scale) 154 { 155 typedef typename VertexConsumer::value_type coord_type; 156 out_vertices.remove_all(); 157 float dx1 = (v1.y - v0.y) / len; 158 float dy1 = (v1.x - v0.x) / len; 159 float dx2 = 0; 160 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 float a1 = atan2(dy1, -dx1); 172 float a2 = a1 + FX_PI; 173 float da = acos(width / (width + ((1.0f / 8) / approximation_scale))) * 2; 174 out_vertices.add(coord_type(v0.x - dx1, v0.y + dy1)); 175 a1 += da; 176 a2 -= da / 4; 177 while (a1 < a2) { 178 out_vertices.add( 179 coord_type(v0.x + (width * cos(a1)), v0.y + (width * sin(a1)))); 180 a1 += da; 181 } 182 out_vertices.add(coord_type(v0.x + dx1, v0.y - dy1)); 183 } 184 } 185 template<class VertexConsumer> 186 void stroke_calc_join(VertexConsumer& out_vertices, 187 const vertex_dist& v0, 188 const vertex_dist& v1, 189 const vertex_dist& v2, 190 float len1, 191 float len2, 192 float width, 193 line_join_e line_join, 194 inner_join_e inner_join, 195 float miter_limit, 196 float inner_miter_limit, 197 float approximation_scale) 198 { 199 typedef typename VertexConsumer::value_type coord_type; 200 float dx1, dy1, dx2, dy2; 201 dx1 = width * (v1.y - v0.y) / len1; 202 dy1 = width * (v1.x - v0.x) / len1; 203 dx2 = width * (v2.y - v1.y) / len2; 204 dy2 = width * (v2.x - v1.x) / len2; 205 out_vertices.remove_all(); 206 if(calc_point_location(v0.x, v0.y, v1.x, v1.y, v2.x, v2.y) > 0) { 207 switch(inner_join) { 208 default: 209 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 210 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 211 break; 212 case inner_miter: 213 stroke_calc_miter(out_vertices, 214 v0, v1, v2, dx1, dy1, dx2, dy2, 215 width, 216 miter_join_revert, 217 inner_miter_limit, 218 1.0f); 219 break; 220 case inner_jag: 221 case inner_round: { 222 float d = (dx1 - dx2) * (dx1 - dx2) + (dy1 - dy2) * (dy1 - dy2); 223 if(d < len1 * len1 && d < len2 * len2) { 224 stroke_calc_miter(out_vertices, 225 v0, v1, v2, dx1, dy1, dx2, dy2, 226 width, 227 miter_join_revert, 228 inner_miter_limit, 229 1.0f); 230 } else { 231 if(inner_join == inner_jag) { 232 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 233 out_vertices.add(coord_type(v1.x, v1.y )); 234 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 235 } else { 236 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 237 out_vertices.add(coord_type(v1.x, v1.y )); 238 stroke_calc_arc(out_vertices, 239 v1.x, v1.y, dx2, -dy2, dx1, -dy1, 240 width, approximation_scale); 241 out_vertices.add(coord_type(v1.x, v1.y )); 242 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 243 } 244 } 245 } 246 break; 247 } 248 } else { 249 switch(line_join) { 250 case miter_join: 251 case miter_join_revert: 252 case miter_join_round: 253 stroke_calc_miter(out_vertices, 254 v0, v1, v2, dx1, dy1, dx2, dy2, 255 width, 256 line_join, 257 miter_limit, 258 approximation_scale); 259 break; 260 case round_join: 261 stroke_calc_arc(out_vertices, 262 v1.x, v1.y, dx1, -dy1, dx2, -dy2, 263 width, approximation_scale); 264 break; 265 default: 266 out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1)); 267 out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2)); 268 break; 269 } 270 } 271 } 272 } 273 #endif 274
