/* -*-ePiX-*- */
#include "epix.h"
using namespace ePiX;

int main()
{
  bounding_box(P(-1,-1),P(1,1));
  unitlength("1in");
  picture(6,6);

  begin();

  red(0.6);
  grid(4,4);

  // produces points with coord "exactly" +/-0.5
  data_file test(Cos, Sin, 0, 2*M_PI, 180);

  data_file copy(test);

  // mark all points
  green(0.6);
  dot_size(6);
  test.plot(BOX);


  // should keep points with y=-0.5, discard y=0.5
  dot_size();
  data_mask DM("[-0.5, 0.5)");

  test.prune(DM, 2); // act on column 2

  // pruned points; keeps y=0.5, discards y=-0.5...
  blue();
  test.plot(BBOX);

  // "reverse-pruned" points
  copy.prune(DM.reverse(), 2);
  yellow();
  copy.plot(BBOX);

  end();
}