void rot4(GdkPixbuf *src, GdkPixbuf *dist, gint r, gfloat m)
{
  gint  w1, h1, w2, h2;
  gint  x1, y1, x2, y2;
  gint  dx1, dy1, dx2, dy2;
  gint  px1, py1, px2, py2;
  gint  i, j;
  guint32  *ptr2;

  w1 = gdk_pixbuf_get_width(src);
  h1 = gdk_pixbuf_get_height(src);
  w2 = gdk_pixbuf_get_width(dist);
  h2 = gdk_pixbuf_get_height(dist);
  px1 = w1 / 2;
  py1 = h1 / 2;
  px2 = w2 / 2;
  py2 = h2 / 2;

  ptr2 = (guint32*)gdk_pixbuf_get_pixels(dist);
  x1 = (((0 - px2) * cos(M_PI*2/360*r) + (0 - py2) * sin(M_PI*2/360*r)) * (1 / m) + px1) * 0x10000;
  y1 = (((0 - py2) * cos(M_PI*2/360*r) - (0 - px2) * sin(M_PI*2/360*r)) * (1 / m) + py1) * 0x10000;
  dx1 = (((1 - px2) * cos(M_PI*2/360*r) + (0 - py2) * sin(M_PI*2/360*r)) * (1 / m) + px1) * 0x10000;
  dy1 = (((0 - py2) * cos(M_PI*2/360*r) - (1 - px2) * sin(M_PI*2/360*r)) * (1 / m) + py1) * 0x10000;
  dx2 = (((0 - px2) * cos(M_PI*2/360*r) + (1 - py2) * sin(M_PI*2/360*r)) * (1 / m) + px1) * 0x10000;
  dy2 = (((1 - py2) * cos(M_PI*2/360*r) - (0 - px2) * sin(M_PI*2/360*r)) * (1 / m) + py1) * 0x10000;
  dx1 -= x1;
  dy1 -= y1;
  dx2 -= x1;
  dy2 -= y1;
  w1 <<= 16;
  h1 <<= 16;
  for(j=0; j<h2; j++) {
    x2 = x1;
    y2 = y1;
    for(i=0; i<w2; i++) {
      if ((x2 >= 0) && (x2 < w1) && (y2 >= 0) && (y2 < h1)) {
	*ptr2 = smooth_pixel(src, x2, y2, dx1, dy1, dx2, dy2, m, m);
      }
      else {
	*ptr2 = 0;
      }
      ptr2++;
      x2 += dx1;
      y2 += dy1;
    }
    x1 += dx2;
    y1 += dy2;
  }
}



/* -------------------------------------------------------------
    ピクセルスムージング
-------------------------------------------------------------- */
guint32 smooth_pixel(GdkPixbuf *pic,
		     gint x, gint y,
		     gint dx1, gint dy1, gint dx2, gint dy2,
		     gfloat mx, gfloat my)
{
  guchar   *ptr1, *ptr2;
  guint     r, g, b, a;
  guint     r1, g1, b1, a1;
  guint     r2, g2, b2, a2;
  guint     ro, go, bo, ao;
  gint      blend, times;
  gint      x_loop, y_loop, tx, ty;

  ro = go = bo = ao = 0;
  blend = 0;

  x_loop = (gint)(1 / mx) + 1;
  y_loop = (gint)(1 / my) + 1;
  dx1 /= x_loop;
  dy1 /= y_loop;
  dx2 /= x_loop;
  dy2 /= y_loop;

  do {
    tx = x;
    ty = y;
    do {
      ptr1 = gdk_pixbuf_get_pixels(pic) +
	gdk_pixbuf_get_rowstride(pic) * (y >> 16) + ((x >> 16) * 4);
      ptr2 = gdk_pixbuf_get_pixels(pic) +
	gdk_pixbuf_get_rowstride(pic) * ((y >> 16) + 1) + ((x >> 16) * 4);

      if (((x >> 16) >= gdk_pixbuf_get_width(pic))
	  || ((y >> 16) >= gdk_pixbuf_get_height(pic))) {
	break;
      }

      r = g = b = a = 0;

      times = (x & 0xffff) >> 8;
      if (times > 0x40) {
	times -= 0x40;
	r1 = ptr1[0] * (0xc0 - times) + ptr1[4] * times;
	g1 = ptr1[1] * (0xc0 - times) + ptr1[5] * times;
	b1 = ptr1[2] * (0xc0 - times) + ptr1[6] * times;
	a1 = ptr1[3] * (0xc0 - times) + ptr1[7] * times;
	r2 = ptr2[0] * (0xc0 - times) + ptr2[4] * times;
	g2 = ptr2[1] * (0xc0 - times) + ptr2[5] * times;
	b2 = ptr2[2] * (0xc0 - times) + ptr2[6] * times;
	a2 = ptr2[3] * (0xc0 - times) + ptr2[7] * times;
      }
      else {
	r1 = ptr1[0] * 0xc0;
	g1 = ptr1[1] * 0xc0;
	b1 = ptr1[2] * 0xc0;
	a1 = ptr1[3] * 0xc0;
	r2 = ptr2[0] * 0xc0;
	g2 = ptr2[1] * 0xc0;
	b2 = ptr2[2] * 0xc0;
	a2 = ptr2[3] * 0xc0;
      }
      times = (y & 0xffff) >> 8;
      if (times > 0x40) {
	times -= 0x40;
	r = r1 * (0xc0 - times) + r2 * times;
	g = g1 * (0xc0 - times) + g2 * times;
	b = b1 * (0xc0 - times) + b2 * times;
	a = a1 * (0xc0 - times) + a2 * times;
      }
      else {
	r = r1 * 0xc0;
	g = g1 * 0xc0;
	b = b1 * 0xc0;
	a = a1 * 0xc0;
      }
      r /= 0xc0 * 0xc0;
      g /= 0xc0 * 0xc0;
      b /= 0xc0 * 0xc0;
      a /= 0xc0 * 0xc0;
      ro += r;
      go += g;
      bo += b;
      ao += a;
      blend++;
      x += dx1;
      y += dy1;
      x_loop--;
    } while(x_loop > 1);
    x = tx;
    y = ty;
    x += dx2;
    y += dy2;
    y_loop--;
  }while(y_loop > 1);

  r = ro / blend;
  g = go / blend;
  b = bo / blend;
  a = ao / blend;

  if (r > 0x100) r = 0xff;
  if (g > 0x100) g = 0xff;
  if (b > 0x100) b = 0xff;
  if (a > 0x100) a = 0xff;
  return(r | (g<<8) | (b<<16) | (a<<24));
}