protected function writeGradientFill(XMLWriter $objWriter, Fill $oFill)
{
$objWriter->startElement('draw:gradient');
$objWriter->writeAttribute('draw:name', 'gradient_' . $oFill->getHashCode());
$objWriter->writeAttribute('draw:display-name', 'gradient_' . $oFill->getHashCode());
$objWriter->writeAttribute('draw:style', 'linear');
$objWriter->writeAttribute('draw:start-intensity', '100%');
$objWriter->writeAttribute('draw:end-intensity', '100%');
$objWriter->writeAttribute('draw:start-color', '#' . $oFill->getStartColor()->getRGB());
$objWriter->writeAttribute('draw:end-color', '#' . $oFill->getEndColor()->getRGB());
$objWriter->writeAttribute('draw:border', '0%');
$objWriter->writeAttribute('draw:angle', $oFill->getRotation() - 90);
$objWriter->endElement();
$this->arrayGradient[] = $oFill->getHashCode();
}