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

void Arrow(const P& tail, const P& head, double t = 0.5)
{
  P tmp(tail + t*(head - tail));
  line(tmp, head);
  arrow(tail, tmp);
}

void Arrow(const P& tail, const P& head, double t,
	   const P& offset, const std::string& msg, epix_label_posn al)
{
  P tmp(tail + t*(head - tail));
  line(tmp, head);
  arrow(tail, tmp);

  label(tmp, offset, msg, al);
}

int main()
{
  picture(P(-3, -2), P(3, 2), "4.5 x 3in");

  begin();
  arrow_width(6);
  arrow_ratio(2);
  arrow_inset(0.75);

  double mx(2), my(1.5);

  P O(0, 0), p0(mx, my), p1(-mx, my), p2(-mx, -my), p3(mx, -my);

  bold();

  line(P(xmin(), 0), P(xmax(), 0));
  line(P(0, ymin()), P(0, ymax()));

  rect(p2, p0);

  label(P(xmin(), 0), P(0, -4), "$X'$", b);
  label(P(xmax(), 0), P(0, -4), "$X$", b);

  label(P(0, ymin(), 0), P(-2, 0), "$Y'$", l);
  label(P(0, ymax(), 0), P(-2, 0), "$Y$", l);

  label(O, P(-2, -4), "$O$", bl);

  label(p0 & E_1, P(2, -4), "$M$", br);
  label(p1 & E_1, P(2, 2), "$M'$", tr);

  label(p0 & E_2, P(2, 2), "$N$", tr);
  label(p2 & E_2, P(2, 2), "$N'$", tr);

  dot(p0, P(0, 2), "$P$", t);
  dot(p1, P(0, 2), "$P'$", t);

  dot(p2, P(0, -4), "$P''$", b);
  dot(p3, P(0, -4), "$P'''$", b);

  label(P(0.5*mx, 0), P(0, -4), "$x$", b);
  label(P(-0.5*mx, 0), P(0, -4), "$x'$", b);

  label(P(0, 0.5*my), P(2, 0), "$y$", r);
  label(P(0, -0.5*my), P(2, 0), "$y'$", r);

  label(P(mx, 0.5*my), P(2, 0), "$y$", r);
  label(P(mx, -0.5*my), P(2, 0), "$y'$", r);

  label(P(-mx, 0.5*my), P(-2, 0), "$y$", l);
  label(P(-mx, -0.5*my), P(-2, 0), "$y'$", l);

  dashed();
  dash_size(2);
  Arrow(O, p0, 0.8);

  tikz_format();
  end();
}