mirror of https://github.com/CGAL/cgal
79 lines
2.4 KiB
C++
79 lines
2.4 KiB
C++
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
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#include <CGAL/Polyline_simplification_2/simplify.h>
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#include <iostream>
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#include <string>
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#include <vector>
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typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
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typedef CGAL::Point_2<K> Point;
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typedef std::vector<Point> Polyline_2;
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namespace PS = CGAL::Polyline_simplification_2;
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typedef PS::Vertex_base_2<K> Vb;
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typedef CGAL::Constrained_triangulation_face_base_2<K> Fb;
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typedef CGAL::Triangulation_data_structure_2<Vb, Fb> TDS;
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typedef CGAL::Constrained_Delaunay_triangulation_2<K, TDS, CGAL::Exact_predicates_tag> CDT;
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typedef CGAL::Constrained_triangulation_plus_2<CDT> CT;
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typedef PS::Stop_below_count_ratio_threshold Stop;
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typedef PS::Squared_distance_cost Cost;
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void print_coords(Polyline_2 polyline) {
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std::cout << std::endl;
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std::cout << "Simplified coordinates:" << std::endl << std::endl;
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// Print out the simplified coordinates
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unsigned int i = 0;
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for (Point coord : polyline) {
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std::cout << "[ ";
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std::cout << coord.x();
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std::cout << ", ";
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std::cout << coord.y();
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std::cout << " ]";
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if (i != polyline.size() - 1) std::cout << ",";
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i++;
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}
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std::cout << std::endl << std::endl;
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}
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void simplify_test() {
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// Hard code a minimum working example where running PS::simplify results in
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// self-intersections. There are no self-intersections when {27, 9} is
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// omitted.
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std::vector<std::vector<int>> coords = {
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{64, 20}, {33, 27}, {27, 9}, {33, 18}, {44, 18}, {44, 8},
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{24, 0}, {0, 13}, {9, 49}, {84, 41}, {83, 29}, {64, 20},
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};
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// Simplification outputs:
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// [ 64, 20 ],[ 27, 9 ],[ 44, 18 ],[ 24, 0 ],
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// [ 9, 49 ],[ 83, 29 ],[ 64, 20 ],[ 64, 20 ]
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// Create polyline for simplifying later
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Polyline_2 polyline;
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// Insert coordinates into polyline
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for (std::vector<int> coord : coords) {
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Point pt(coord[0], coord[1]);
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polyline.push_back(pt);
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}
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// Insert polyline into ct and run simplify()
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CT ct;
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ct.insert_constraint(polyline.begin(), polyline.end());
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PS::simplify(ct, Cost(), Stop(0.2));
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Polyline_2 polyline_simplified;
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// Transfer simplified coordinates from ct to polyline for easy handling
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auto cit = ct.constraints_begin();
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for (auto vit = ct.points_in_constraint_begin(*cit);
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vit != ct.points_in_constraint_end(*cit); vit++) {
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polyline_simplified.push_back(*vit);
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}
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print_coords(polyline_simplified);
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assert(polyline_simplified.size() == 4);
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}
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int main() {
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simplify_test();
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}
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