void exportXmlTemplate( XmlWriter xml, String legend ) {
		if(yVal1 == yVal2 && xVal1 != xVal2) {
			// hrule
			xml.startTag("hrule");
			xml.writeTag("value", yVal1);
			xml.writeTag("color", color);
			xml.writeTag("legend", legend);
			xml.writeTag("width", lineWidth);
			xml.closeTag(); // hrule
		}
		else if(yVal1 != yVal2 && xVal1 == xVal2) {
			// vrule
			xml.startTag("vrule");
			xml.writeTag("time", xVal1);
			xml.writeTag("color", color);
			xml.writeTag("legend", legend);
			xml.writeTag("width", lineWidth);
			xml.closeTag(); // vrule
		}
		else if(yVal1 != yVal2 && xVal1 != xVal2) {
			// general line
			xml.startTag("line");
			xml.writeTag("time1", xVal1);
			xml.writeTag("value1", yVal1);
			xml.writeTag("time2", xVal2);
			xml.writeTag("value2", yVal2);
			xml.writeTag("color", color);
			xml.writeTag("legend", legend);
			xml.writeTag("width", lineWidth);
			xml.closeTag(); //line
		}
	}