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Merge pull request #3230 from MaelRL/Polygon_2-Fix_filter_collinear_points-GF 

Polygon: Fix `filter_collinear_points()` early return
This commit is contained in:
Laurent Rineau 2018-07-16 11:12:59 +02:00
parent 919b9afe92 fa6b5af9de
commit e92a3770f4
2 changed files with 23 additions and 7 deletions
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9
Polygon/include/CGAL/Polygon_2/Polygon_2_algorithms_impl.h
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@ -60,6 +60,8 @@ namespace Polygon_2 {
// by three consecutive points of the range (more specifically,
// on the value of the determinant).
//
// \pre The range `(first, beyond)` is composed of at least three points.
// \pre Not all points in the range `(first, beyond)` are (almost) collinear.
template<typename K, typename InputForwardIterator, typename OutputForwardIterator>
OutputForwardIterator filter_collinear_points(InputForwardIterator first,
InputForwardIterator beyond,
@ -67,8 +69,7 @@ OutputForwardIterator filter_collinear_points(InputForwardIterator first,
const typename K::FT tolerance =
std::numeric_limits<typename K::FT>::epsilon())
{
if(std::distance(first, beyond) < 4)
return out;
CGAL_precondition(std::distance(first, beyond) >= 3);
typedef typename K::FT FT;
typedef typename K::Point_2 Point;
@ -83,7 +84,9 @@ OutputForwardIterator filter_collinear_points(InputForwardIterator first,
do
{
CGAL_assertion(vit != vit_next && vit_next != vit_next_2 && vit != vit_next_2);
CGAL_assertion(vit != vit_next);
CGAL_assertion(vit_next != vit_next_2);
CGAL_assertion(vit != vit_next_2);
const Point& o = *vit;
const Point& p = *vit_next;

21
Polygon/test/Polygon/AlgorithmTest.cpp
View File

@ -20,7 +20,7 @@ void test_collinear_point_filtering(const R&, const char* FileName)
std::ifstream from(FileName);
if (!from) {
std::cerr << "could not open file " << FileName << "!" << endl;
std::cerr << "Could not open file " << FileName << "!" << endl;
std::exit(1);
}
CGAL::set_ascii_mode(from);
@ -35,20 +35,33 @@ void test_collinear_point_filtering(const R&, const char* FileName)
std::cout << std::endl;
std::vector<Point> simplified_polygon;
std::size_t final_size;
// check for 3 points
CGAL::internal::Polygon_2::filter_collinear_points<R>(polygon.begin(), polygon.begin() + 3,
std::back_inserter(simplified_polygon),
0 /*tolerance*/);
final_size = simplified_polygon.size();
std::cout << "final size: " << final_size << std::endl;
assert(final_size == 3);
// generic tests
simplified_polygon.clear();
CGAL::internal::Polygon_2::filter_collinear_points<R>(polygon.begin(), polygon.end(),
std::back_inserter(simplified_polygon),
0 /*tolerance*/);
std::size_t final_size = simplified_polygon.size();
final_size = simplified_polygon.size();
std::cout << "final size (tolerance 0): " << final_size << std::endl;
CGAL_assertion(final_size == 7);
assert(final_size == 7);
// --
simplified_polygon.clear();
CGAL::internal::Polygon_2::filter_collinear_points<R>(polygon.begin(), polygon.end(),
std::back_inserter(simplified_polygon),
1e-10);
final_size = simplified_polygon.size();
std::cout << "final size (tolerance 1e-10): " << final_size << std::endl;
CGAL_assertion(final_size == 5);
assert(final_size == 5);
std::cout << "simplified polygon:" << std::endl;
std::copy(simplified_polygon.begin(), simplified_polygon.end(), std::ostream_iterator<Point>(std::cout, "\n"));