Geometry Boost List: Re: [geometry] Accuray issue with geometry::difference() in version Boost 1.57

Subject: Re: [geometry] Accuray issue with geometry::difference() in version Boost 1.57
From: Mikkel B. Stegmann (mikkel.stegmann_at_[hidden])
Date: 2015-04-17 04:47:00

Hi Menalaos,

somehow the results and code (including input data) got stripped in the
mail-version of my post. Here it is without raw-tags:

Result using Boost v1.55:

         249.232           761.09
         249.232           760.98
          265.89           760.98
          265.89          729.219
          94.021          729.219
          94.021           761.09
         249.232           761.09

Result using Boost v1.57:

249.232003466816           761.09
         249.232           760.98
          265.89 760.979984987659
          265.89          729.219
          94.021          729.219
          94.021           761.09
249.232003466816           761.09

----
#include <boost/foreach.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry.hpp>
#include <cstdio>
#include <assert.h>
int main() {
  // 2D point with double precision
  typedef boost::geometry::model::d2::point_xy<double> BoostPoint;
  // 2D polygon, ring type: clockwise, closed ("the first point must be
spatially equal to the last point")
  typedef boost::geometry::model::polygon<BoostPoint> BoostPolygon;
  BoostPolygon rectangleA;
  rectangleA.outer().push_back(BoostPoint( 94.021, 729.219)); // clock-wise
points
  rectangleA.outer().push_back(BoostPoint( 94.021, 761.090));
  rectangleA.outer().push_back(BoostPoint(265.890, 761.090));
  rectangleA.outer().push_back(BoostPoint(265.890, 729.219));
  rectangleA.outer().push_back(BoostPoint( 94.021, 729.219)); // close
  BoostPolygon rectangleB;
  rectangleB.outer().push_back(BoostPoint(249.232, 760.980)); // clock-wise
points
  rectangleB.outer().push_back(BoostPoint(249.232, 780.980));
  rectangleB.outer().push_back(BoostPoint(319.232, 780.980));
  rectangleB.outer().push_back(BoostPoint(319.232, 760.980));
  rectangleB.outer().push_back(BoostPoint(249.232, 760.980)); // close
  std::list<BoostPolygon> differencePolygons;
  boost::geometry::difference(rectangleA, rectangleB, differencePolygons);
  assert(differencePolygons.size()==1);
  BOOST_FOREACH(const BoostPoint &point, differencePolygons.front().outer())
{
    printf("%16.15g %16.15g\n", point.x(), point.y());
  }
  return 0;
}
--
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