code: function updateRectHandles(parent) {
  	var handle, h;
  	if (parent._handles) {
  		// Move handles when dragging
  		for (h = 0; h < parent._handles.length; h += 1) {
  			handle = parent._handles[h];
  			handle.x = parent.x + ((parent.width / 2 * handle._px) + ((parent.fromCenter) ? 0 : parent.width / 2));
  			handle.y = parent.y + ((parent.height / 2 * handle._py) + ((parent.fromCenter) ? 0 : parent.height / 2));
  		}
  	}
  	updateRectGuides(parent);
  }
docs: Update position of handles according to size and dimensions of rectangular layer