public function addXfWriter($style, $isStyleXf = false)
	{
		$xfWriter = new PHPExcel_Writer_Excel5_Xf($style);
		$xfWriter->setIsStyleXf($isStyleXf);

		// Add the font if not already added
		$fontIndex = $this->_addFont($style->getFont());

		// Assign the font index to the xf record
		$xfWriter->setFontIndex($fontIndex);

		// Background colors, best to treat these after the font so black will come after white in custom palette
		$xfWriter->setFgColor($this->_addColor($style->getFill()->getStartColor()->getRGB()));
		$xfWriter->setBgColor($this->_addColor($style->getFill()->getEndColor()->getRGB()));
		$xfWriter->setBottomColor($this->_addColor($style->getBorders()->getBottom()->getColor()->getRGB()));
		$xfWriter->setTopColor($this->_addColor($style->getBorders()->getTop()->getColor()->getRGB()));
		$xfWriter->setRightColor($this->_addColor($style->getBorders()->getRight()->getColor()->getRGB()));
		$xfWriter->setLeftColor($this->_addColor($style->getBorders()->getLeft()->getColor()->getRGB()));
		$xfWriter->setDiagColor($this->_addColor($style->getBorders()->getDiagonal()->getColor()->getRGB()));

		// Add the number format if it is not a built-in one and not already added
		if ($style->getNumberFormat()->getBuiltInFormatCode() === false) {
			$numberFormatHashCode = $style->getNumberFormat()->getHashCode();

			if (isset($this->_addedNumberFormats[$numberFormatHashCode])) {
				$numberFormatIndex = $this->_addedNumberFormats[$numberFormatHashCode];
			} else {
				$numberFormatIndex = 164 + count($this->_numberFormats);
				$this->_numberFormats[$numberFormatIndex] = $style->getNumberFormat();
				$this->_addedNumberFormats[$numberFormatHashCode] = $numberFormatIndex;
			}
		} else {
			$numberFormatIndex = (int) $style->getNumberFormat()->getBuiltInFormatCode();
		}

		// Assign the number format index to xf record
		$xfWriter->setNumberFormatIndex($numberFormatIndex);

		$this->_xfWriters[] = $xfWriter;

		$xfIndex = count($this->_xfWriters) - 1;
		return $xfIndex;
	}