/*  call-seq:
 *    draw_box(point1, point2, color)
 *
 *  Draw a non-solid box (rectangle) on the Surface, given the coordinates of
 *  its top-left corner and bottom-right corner. See also #draw_box_s
 *
 *  This method takes these arguments:
 *  point1::  the coordinates of top-left corner, [x1,y1].
 *  point2::  the coordinates of bottom-right corner, [x2,y2].
 *  color::   the color of the shape, [r,g,b,a]. If alpha
 *            is omitted, it is drawn at full opacity.
 */
VALUE rbgm_draw_rect(VALUE target, VALUE pt1, VALUE pt2, VALUE rgba)
{
  draw_rect(target,pt1,pt2,rgba,0); /* no fill */
  return target;
}