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

const P LdY(0, 4);
const P LdX(4, 0);

std::string sfmt(const std::string& msg)
{
#ifdef SANSSERIF
  return "$\\mathsf{"+msg+"}$";
#else
  return "$"+msg+"$";
#endif
}

const double K(0.25);
const double ht(1.5);

const double X0(0.75);
const double dX(0.05);

P f(double t)
{
  return P(K*(1 + 2.5*t)*t, t);
}

P g(double t)
{
  return P(K*t, t);
}

int main()
{
  picture(P(0, 0), P(1,1), "3 x 2in");

  begin();

  P ptA(0,0), ptC(f(1)), ptD(g(1)), ptB(ptC - ptD);
  P ptM(g(X0)), ptN(g(X0+dX)), ptP(f(X0)), ptQ(f(X0+dX)), ptR(ptP+ptN-ptM);

  plot(f, 0, 1.125, 40);

  quad(ptA, ptB, ptC, ptD);
  quad(ptM, ptP, ptR, ptN);
  line(ptQ, ptR);

  label(ptA, -LdY, sfmt("A"), b);
  label(ptB, -LdY, sfmt("B"), b);

  label(ptM, -LdX, sfmt("M"), bl);
  label(ptN, -LdX, sfmt("N"), tl);
  label(ptD, -LdX, sfmt("D"), l);

  label(ptC,  LdX, sfmt("C"), br);

  label(ptR,  LdY, sfmt("R"), t);

  label(ptP, -LdY, sfmt("P"), b);
  label(ptQ, -LdY, sfmt("Q"), r);

  tikz_format();
  end();
}