in thumbnails4j-xlsx/src/main/java/co/elastic/thumbnails4j/xlsx/XLSXThumbnailer.java [71:80]
private List<BufferedImage> getThumbnails(Workbook workbook, List<Dimensions> dimensions) {
XlsxToHtmlSerializer serializer = new XlsxToHtmlSerializer(workbook);
byte[] htmlBytes = serializer.getHtml();
BufferedImage image = ThumbnailUtils.clipHtmlToImage(htmlBytes, ThumbnailUtils.getMaxInMemoryBuffer());
List<BufferedImage> results = new ArrayList<>();
for(Dimensions singleDimension: dimensions){
results.add(ThumbnailUtils.scaleImage(image, singleDimension));
}
return results;
}