/usr/include/mapnik/simplify_converter.hpp is in libmapnik-dev 2.2.0+ds1-6build2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 | #ifndef MAPNIK_SIMPLIFY_CONVERTER_HPP
#define MAPNIK_SIMPLIFY_CONVERTER_HPP
// mapnik
#include <mapnik/config.hpp>
#include <mapnik/box2d.hpp>
#include <mapnik/vertex.hpp>
#include <mapnik/simplify.hpp>
#include <mapnik/noncopyable.hpp>
// stl
#include <limits>
#include <set>
#include <vector>
#include <deque>
#include <cmath>
#include <stdexcept>
// boost
#include <boost/optional.hpp>
namespace mapnik
{
struct weighted_vertex : private mapnik::noncopyable
{
vertex2d coord;
double weight;
weighted_vertex *prev;
weighted_vertex *next;
weighted_vertex(vertex2d coord_) :
coord(coord_),
weight(std::numeric_limits<double>::infinity()),
prev(NULL),
next(NULL) {}
double nominalWeight()
{
if (prev == NULL || next == NULL || coord.cmd != SEG_LINETO) {
return std::numeric_limits<double>::infinity();
}
vertex2d const& A = prev->coord;
vertex2d const& B = next->coord;
vertex2d const& C = coord;
return std::abs((double)((A.x - C.x) * (B.y - A.y) - (A.x - B.x) * (C.y - A.y))) / 2.0;
}
struct ascending_sort
{
bool operator() (const weighted_vertex *a, const weighted_vertex *b)
{
return b->weight > a->weight;
}
};
};
struct sleeve
{
vertex2d v[5];
sleeve(vertex2d const& v0, vertex2d const& v1, double offset)
{
double a = std::atan2((v1.y - v0.y), (v1.x - v0.x));
double dx = offset * std::cos(a);
double dy = offset * std::sin(a);
v[0].x = v0.x + dy;
v[0].y = v0.y - dx;
v[1].x = v0.x - dy;
v[1].y = v0.y + dx;
v[2].x = v1.x - dy;
v[2].y = v1.y + dx;
v[3].x = v1.x + dy;
v[3].y = v1.y - dx;
v[4].x = v0.x + dy;
v[4].y = v0.y - dx;
}
bool inside(vertex2d const& q)
{
bool inside=false;
for (unsigned i=0;i<4;++i)
{
if ((((v[i+1].y <= q.y) && (q.y < v[i].y)) ||
((v[i].y <= q.y) && (q.y < v[i+1].y))) &&
(q.x < (v[i].x - v[i+1].x) * (q.y - v[i+1].y)/ (v[i].y - v[i+1].y) + v[i+1].x))
inside=!inside;
}
return inside;
}
void print()
{
std::cerr << "LINESTRING("
<< v[0].x << " " << -v[0].y << ","
<< v[1].x << " " << -v[1].y << ","
<< v[2].x << " " << -v[2].y << ","
<< v[3].x << " " << -v[3].y << ","
<< v[0].x << " " << -v[0].y << ")" << std::endl;
}
};
template <typename Geometry>
struct MAPNIK_DECL simplify_converter
{
public:
simplify_converter(Geometry& geom)
: geom_(geom),
tolerance_(0.0),
status_(initial),
algorithm_(radial_distance),
pos_(0)
{}
enum status
{
initial,
process,
closing,
end,
cache
};
simplify_algorithm_e get_simplify_algorithm()
{
return algorithm_;
}
void set_simplify_algorithm(simplify_algorithm_e value)
{
if (algorithm_ != value)
{
algorithm_ = value;
reset();
}
}
double get_simplify_tolerance()
{
return tolerance_;
}
void set_simplify_tolerance(double value)
{
if (tolerance_ != value) {
tolerance_ = value;
reset();
}
}
void reset()
{
geom_.rewind(0);
vertices_.clear();
status_ = initial;
pos_ = 0;
}
void rewind(unsigned int) const
{
pos_ = 0;
}
unsigned vertex(double* x, double* y)
{
if (tolerance_ == 0.0)
return geom_.vertex(x, y);
if (status_ == initial)
init_vertices();
return output_vertex(x, y);
}
private:
unsigned output_vertex(double* x, double* y)
{
switch (algorithm_)
{
case visvalingam_whyatt:
return output_vertex_cached(x, y);
case radial_distance:
return output_vertex_distance(x, y);
case zhao_saalfeld:
return output_vertex_sleeve(x, y);
default:
throw std::runtime_error("simplification algorithm not yet implemented");
}
return SEG_END;
}
unsigned output_vertex_cached(double* x, double* y) {
if (pos_ >= vertices_.size())
return SEG_END;
previous_vertex_ = vertices_[pos_];
*x = previous_vertex_.x;
*y = previous_vertex_.y;
pos_++;
return previous_vertex_.cmd;
}
unsigned output_vertex_distance(double* x, double* y) {
if (status_ == closing) {
status_ = end;
return SEG_CLOSE;
}
vertex2d last(vertex2d::no_init);
vertex2d vtx(vertex2d::no_init);
while ((vtx.cmd = geom_.vertex(&vtx.x, &vtx.y)) != SEG_END)
{
if (vtx.cmd == SEG_LINETO) {
if (distance_to_previous(vtx) > tolerance_) {
// Only output a vertex if it's far enough away from the previous
break;
} else {
last = vtx;
// continue
}
} else if (vtx.cmd == SEG_CLOSE) {
if (last.cmd == vertex2d::no_init) {
// The previous vertex was already output in the previous call.
// We can now safely output SEG_CLOSE.
status_ = end;
} else {
// We eliminated the previous point because it was too close, but
// we have to output it now anyway, since this is the end of the
// vertex stream. Make sure that we output SEG_CLOSE in the next call.
vtx = last;
status_ = closing;
}
break;
} else if (vtx.cmd == SEG_MOVETO) {
break;
} else {
throw std::runtime_error("Unknown vertex command");
}
}
previous_vertex_ = vtx;
*x = vtx.x;
*y = vtx.y;
return vtx.cmd;
}
template <typename Iterator>
bool fit_sleeve(Iterator itr,Iterator end, vertex2d const& v)
{
sleeve s(*itr,v,tolerance_);
++itr; // skip first vertex
for (; itr!=end; ++itr)
{
if (!s.inside(*itr))
{
return false;
}
}
return true;
}
unsigned output_vertex_sleeve(double* x, double* y)
{
vertex2d vtx(vertex2d::no_init);
std::size_t min_size = 1;
while ((vtx.cmd = geom_.vertex(&vtx.x, &vtx.y)) != SEG_END)
{
//if ((std::fabs(vtx.x - previous_vertex_.x) < 0.5) &&
// (std::fabs(vtx.y - previous_vertex_.y) < 0.5))
// continue;
if (status_ == cache &&
vertices_.size() >= min_size)
status_ = process;
previous_vertex_ = vtx;
if (vtx.cmd == SEG_MOVETO)
{
if (sleeve_cont_.size() > 1)
{
vertices_.push_back(sleeve_cont_.back());
sleeve_cont_.clear();
}
vertices_.push_back(vtx);
sleeve_cont_.push_back(vtx);
if (status_ == process) break;
}
else if (vtx.cmd == SEG_LINETO)
{
if (sleeve_cont_.size() > 1 && !fit_sleeve(sleeve_cont_.begin(), sleeve_cont_.end(), vtx))
{
vertex2d last = vtx;
vtx = sleeve_cont_.back();
sleeve_cont_.clear();
sleeve_cont_.push_back(vtx);
sleeve_cont_.push_back(last);
vertices_.push_back(vtx);
if (status_ == process) break;
}
else
{
sleeve_cont_.push_back(vtx);
}
}
else if (vtx.cmd == SEG_CLOSE)
{
if (sleeve_cont_.size() > 1)
{
vertices_.push_back(sleeve_cont_.back());
sleeve_cont_.clear();
}
vertices_.push_back(vtx);
if (status_ == process) break;
}
}
if (status_ == cache)
{
if (vertices_.size() < min_size)
return SEG_END;
status_ = process;
}
if (vtx.cmd == SEG_END)
{
if (sleeve_cont_.size() > 1)
{
vertices_.push_back(sleeve_cont_.back());
}
sleeve_cont_.clear();
vertices_.push_back(vtx);
}
if (vertices_.size() > 0)
{
vertex2d v = vertices_.front();
vertices_.pop_front();
*x = v.x;
*y = v.y;
return v.cmd;
}
return SEG_END;
}
double distance_to_previous(vertex2d const& vtx) {
double dx = previous_vertex_.x - vtx.x;
double dy = previous_vertex_.y - vtx.y;
return dx * dx + dy * dy;
}
status init_vertices()
{
if (status_ != initial) // already initialized
return status_;
reset();
switch (algorithm_) {
case visvalingam_whyatt:
return init_vertices_visvalingam_whyatt();
case radial_distance:
// Use
vertices_.push_back(vertex2d(vertex2d::no_init));
return status_ = process;
case zhao_saalfeld:
return status_ = cache;
default:
throw std::runtime_error("simplification algorithm not yet implemented");
}
}
status init_vertices_visvalingam_whyatt()
{
typedef std::set<weighted_vertex *, weighted_vertex::ascending_sort> VertexSet;
typedef std::vector<weighted_vertex *> VertexList;
std::vector<weighted_vertex *> v_list;
vertex2d vtx(vertex2d::no_init);
while ((vtx.cmd = geom_.vertex(&vtx.x, &vtx.y)) != SEG_END)
{
v_list.push_back(new weighted_vertex(vtx));
}
if (v_list.empty()) {
return status_ = process;
}
// Connect the vertices in a linked list and insert them into the set.
VertexSet v;
for (VertexList::iterator i = v_list.begin(); i != v_list.end(); ++i)
{
(*i)->prev = i == v_list.begin() ? NULL : *(i - 1);
(*i)->next = i + 1 == v_list.end() ? NULL : *(i + 1);
(*i)->weight = (*i)->nominalWeight();
v.insert(*i);
}
// Use Visvalingam-Whyatt algorithm to calculate each point's weight.
while (v.size() > 0)
{
VertexSet::iterator lowest = v.begin();
weighted_vertex *removed = *lowest;
if (removed->weight >= tolerance_) {
break;
}
v.erase(lowest);
// Connect adjacent vertices with each other
if (removed->prev) removed->prev->next = removed->next;
if (removed->next) removed->next->prev = removed->prev;
// Adjust weight and reinsert prev/next to move them to their correct position.
if (removed->prev) {
v.erase(removed->prev);
removed->prev->weight = std::max(removed->weight, removed->prev->nominalWeight());
v.insert(removed->prev);
}
if (removed->next) {
v.erase(removed->next);
removed->next->weight = std::max(removed->weight, removed->next->nominalWeight());
v.insert(removed->next);
}
}
v.clear();
// Traverse the remaining list and insert them into the vertex cache.
for (VertexList::iterator i = v_list.begin(); i != v_list.end(); ++i)
{
if ((*i)->weight >= tolerance_)
{
vertices_.push_back((*i)->coord);
}
delete *i;
}
// Initialization finished.
return status_ = process;
}
Geometry& geom_;
double tolerance_;
status status_;
simplify_algorithm_e algorithm_;
std::deque<vertex2d> vertices_;
std::deque<vertex2d> sleeve_cont_;
vertex2d previous_vertex_;
mutable size_t pos_;
};
}
#endif // MAPNIK_SIMPLIFY_CONVERTER_HPP
|