code: function (rect) {
  			return Crafty.viewport._x + rect._x + rect._w > 0 && Crafty.viewport._y + rect._y + rect._h > 0 &&
  				   Crafty.viewport._x + rect._x < Crafty.viewport.width && Crafty.viewport._y + rect._y < Crafty.viewport.height;
  		}
docs: @
  #Crafty.DrawManager.onScreen
  @comp Crafty.DrawManager
  @sign public Crafty.DrawManager.onScreen(Object rect)
  @param rect - A rectangle with field {_x: x_val, _y: y_val, _w: w_val, _h: h_val}
  
  Test if a rectangle is completely in viewport