code: public function setZoomLevel($zoomLevel)
  	{
  		$zoomLevel = (int) $zoomLevel;
  
  		if ($zoomLevel < 0 || $zoomLevel > 100)
  		{
  			throw new \InvalidArgumentException('Zoom level must be between 0 and 100!');
  		}
  
  		$this->zoomLevel = $zoomLevel;
  
  		return $this;
  	}
docs: Set the zoom level
  
  @param integer $zoomLevel The zoom level
  
  @return $this The object instance
  
  @throws \InvalidArgumentException If the zoom level is out of bounds