Use of uninitialized variable in NGon2D.ih

[danoan]

In line 98 of file DGtal/shapes/parametric/NGon2D.ih, the variable angle uses itself in its definition

  const double angle = t - myPhi + (angle < 0.0 ? NGON2D_2_PI : 0.);

I suggest to rewrite as

  double angle = t - myPhi;
  angle = (angle < 0.0) ? angle + NGON2D_2_PI : angle;

A consequence of this error can be materialized by digitizing a triangle

#include <DGtal/helpers/StdDefs.h>
#include <DGtal/io/boards/Board2D.h>

#include <DGtal/shapes/GaussDigitizer.h>
#include <DGtal/shapes/Shapes.h>
#include <DGtal/shapes/parametric/NGon2D.h>

int main(int argc, char* argv[]) {
  using namespace DGtal::Z2i;

  typedef DGtal::NGon2D<Space> Shape;
  double PI = 3.14159265359;
  Shape shape(0,0,20,3,PI/2);

  DGtal::GaussDigitizer<Space, Shape> gd;
  double h =0.5;
  gd.attach(shape);
  gd.init(shape.getLowerBound(), shape.getUpperBound(), h);

  Domain domain(gd.getDomain().lowerBound(),
                gd.getDomain().upperBound());
  DigitalSet output(domain);
  DGtal::Shapes<Domain>::digitalShaper(output, gd);

  DGtal::Board2D board;
  board << output;
  board.saveSVG("triangle.svg");

  return 0;
}

[phcerdan]

Fixed in #1541