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// For complete examples and data files, please go to https://github.com/groupdocs-viewer/GroupDocs.Viewer-for-Java
try {
	// Setup GroupDocs.Viewer config
	ViewerConfig config = Utilities.getConfiguration();

	// Create image handler
	ViewerImageHandler imageHandler = new ViewerImageHandler(config);
	String guid = fileName;

	ImageOptions options = new ImageOptions();

	// Set watermark properties
	Watermark watermark = new Watermark(watermarkText);
	//Set color for watermark with values Red, Green, Blue and Alpha(Transparency) 
	Color watermarkColor = new Color(200, 75, 75, 100);
	watermark.setColor(watermarkColor);
	watermark.setPosition(WatermarkPosition.Diagonal);
	watermark.setWidth(100f);

	options.setWatermark(watermark);

	// Get document pages image representation with watermark
	List<PageImage> pages = imageHandler.getPages(guid, options);
	for (PageImage page : pages) {
		Utilities.saveAsImage(page.getPageNumber() + "_" + fileName, "png", page.getStream());
	}
} catch (Exception exp) {
	System.out.println("Exception: " + exp.getMessage());
	exp.printStackTrace();
}