/*
 *  call-seq:
 *    rotozoom_size( size, angle, zoom )  ->  [width, height] or nil
 *
 *  Return the dimensions of the surface that would be returned if
 *  #rotozoom() were called on a Surface of the given size, with
 *  the same angle and zoom factors.
 *
 *  If Rubygame was compiled with SDL_gfx-2.0.13 or greater, +zoom+ can be
 *  an Array of 2 Numerics for separate X and Y scaling. Also, it can be
 *  negative to indicate flipping horizontally or vertically.
 *
 *  Will return +nil+ if you attempt to use separate X and Y zoom factors
 *  or negative zoom factors with an unsupported version of SDL_gfx.
 *
 *  This method takes these arguments:
 *  size::  an Array with the hypothetical Surface width and height (pixels)
 *  angle:: degrees to rotate counter-clockwise (negative for clockwise).
 *  zoom::  scaling factor(s). A single positive Numeric, unless you have
 *          SDL_gfx-2.0.13 or greater (see above).
 */
VALUE rbgm_transform_rzsize(int argc, VALUE *argv, VALUE module)
{
  int w,h, dstw,dsth;
  double angle, zoomx, zoomy;

  if(argc < 3)
    rb_raise(rb_eArgError,"wrong number of arguments (%d for 3)",argc);
  w = NUM2INT(rb_ary_entry(argv[0],0));
  h = NUM2INT(rb_ary_entry(argv[0],0));
  angle = NUM2DBL(argv[1]);

  if(TYPE(argv[2])==T_ARRAY)
  {
/* Separate X/Y rotozoom scaling was not supported prior to 2.0.13. */
/* Check if we have at least version 2.0.13 of SDL_gfxPrimitives */
#ifdef HAVE_ROTOZOOMXY
    /* Do the real function. */
    zoomx = NUM2DBL(rb_ary_entry(argv[1],0));
    zoomy = NUM2DBL(rb_ary_entry(argv[1],1));
    rotozoomSurfaceSizeXY(w, h, angle, zoomx, zoomy, &dstw, &dsth);

#else 
    /* Return nil, because it's not supported. */
    return Qnil;
#endif

  }
  else if(FIXNUM_P(argv[1]) || TYPE(argv[1])==T_FLOAT)
  {
    zoomx = NUM2DBL(argv[1]);
#ifndef HAVE_ROTOZOOMXY
    if(zoomx < 0)                                                               /* negative zoom (for flipping) */
    {
                        /* Return nil, because it's not supported. */
                        return Qnil;
    }
#endif
    rotozoomSurfaceSize(w, h, angle, zoomx, &dstw, &dsth);
  }
  else
    rb_raise(rb_eArgError,"wrong zoom factor type (expected Array or Numeric)");


  /*   if(dstw == NULL || dsth == NULL)
     rb_raise(eSDLError,"Could not rotozoom surface: %s",SDL_GetError());*/
  return rb_ary_new3(2,INT2NUM(dstw),INT2NUM(dsth));

}