void set_margin_output(double left, double bottom, double right,
                        double top)
 {
     _margin_type = margin_type_e.MarginOutput;
     _margin      = new Vector2Pair(new Vector2(left, bottom), new Vector2(right, top));
     set_window(_window2d_fit, false);
 }
 protected RendererViewport()
 {
     _margin_type   = margin_type_e.MarginRatio;
     _margin        = new Vector2Pair(new Vector2(0.13, 0.13), new Vector2(0.13, 0.13));
     _rows          = 1;
     _cols          = 1;
     _pageid        = 0;
     _fov           = 45.0;
     _page          = Vector2Pair.vector2_pair_00;
     _window2d      = Vector2Pair.vector2_pair_00;
     _window2d_fit  = Vector2Pair.vector2_pair_00;
     _2d_output_res = Vector2.vector2_0;
     //_precision (3), _format ()
 }