public function setStampPosition ( $Xposition, $Yposition) {
		// set X position
		switch ($Xposition) {
			case transparentWatermarkOnLeft: 
			case transparentWatermarkOnCenter:
			case transparentWatermarkOnRight:
			$this->stampPositionX=$Xposition;
			break;
		}
		// set Y position
		switch ($Yposition) {
			case transparentWatermarkOnTop:
			case transparentWatermarkOnMiddle:
			case transparentWatermarkOnBottom:
			$this->stampPositionY=$Yposition;
			break;
		}
	}