void Splash::flattenCurve(SplashCoord x0, SplashCoord y0,
			  SplashCoord x1, SplashCoord y1,
			  SplashCoord x2, SplashCoord y2,
			  SplashCoord x3, SplashCoord y3,
			  SplashCoord *matrix, SplashCoord flatness2,
			  SplashPath *fPath) {
  SplashCoord cx[splashMaxCurveSplits + 1][3];
  SplashCoord cy[splashMaxCurveSplits + 1][3];
  int cNext[splashMaxCurveSplits + 1];
  SplashCoord xl0, xl1, xl2, xr0, xr1, xr2, xr3, xx1, xx2, xh;
  SplashCoord yl0, yl1, yl2, yr0, yr1, yr2, yr3, yy1, yy2, yh;
  SplashCoord dx, dy, mx, my, tx, ty, d1, d2;
  int p1, p2, p3;

  p1 = 0;
  p2 = splashMaxCurveSplits;
  cx[p1][0] = x0;  cy[p1][0] = y0;
  cx[p1][1] = x1;  cy[p1][1] = y1;
  cx[p1][2] = x2;  cy[p1][2] = y2;
  cx[p2][0] = x3;  cy[p2][0] = y3;
  cNext[p1] = p2;

  while (p1 < splashMaxCurveSplits) {

    xl0 = cx[p1][0];  yl0 = cy[p1][0];
    xx1 = cx[p1][1];  yy1 = cy[p1][1];
    xx2 = cx[p1][2];  yy2 = cy[p1][2];
    p2 = cNext[p1];
    xr3 = cx[p2][0];  yr3 = cy[p2][0];

    transform(matrix, (xl0 + xr3) * 0.5, (yl0 + yr3) * 0.5, &mx, &my);
    transform(matrix, xx1, yy1, &tx, &ty);
#if USE_FIXEDPOINT
    d1 = splashDist(tx, ty, mx, my);
#else
    dx = tx - mx;
    dy = ty - my;
    d1 = dx*dx + dy*dy;
#endif
    transform(matrix, xx2, yy2, &tx, &ty);
#if USE_FIXEDPOINT
    d2 = splashDist(tx, ty, mx, my);
#else
    dx = tx - mx;
    dy = ty - my;
    d2 = dx*dx + dy*dy;
#endif

    if (p2 - p1 == 1 || (d1 <= flatness2 && d2 <= flatness2)) {
      fPath->lineTo(xr3, yr3);
      p1 = p2;

    } else {
      xl1 = splashAvg(xl0, xx1);
      yl1 = splashAvg(yl0, yy1);
      xh = splashAvg(xx1, xx2);
      yh = splashAvg(yy1, yy2);
      xl2 = splashAvg(xl1, xh);
      yl2 = splashAvg(yl1, yh);
      xr2 = splashAvg(xx2, xr3);
      yr2 = splashAvg(yy2, yr3);
      xr1 = splashAvg(xh, xr2);
      yr1 = splashAvg(yh, yr2);
      xr0 = splashAvg(xl2, xr1);
      yr0 = splashAvg(yl2, yr1);
      p3 = (p1 + p2) / 2;
      cx[p1][1] = xl1;  cy[p1][1] = yl1;
      cx[p1][2] = xl2;  cy[p1][2] = yl2;
      cNext[p1] = p3;
      cx[p3][0] = xr0;  cy[p3][0] = yr0;
      cx[p3][1] = xr1;  cy[p3][1] = yr1;
      cx[p3][2] = xr2;  cy[p3][2] = yr2;
      cNext[p3] = p2;
    }
  }
}

Unknown