// For complete examples and data files, please go to https://github.com/groupdocs-watermark/GroupDocs.Watermark-for-.NET
using (DiagramDocument doc = Document.Load<DiagramDocument>(Utilities.MapSourceFilePath(FilePath)))
{
// Add text watermark
TextWatermark textWatermark = new TextWatermark("Test watermark", new Font("Calibri", 19));
doc.Pages[0].AddWatermark(textWatermark);
// Add image watermark
using (ImageWatermark imageWatermark = new ImageWatermark(@"D:\logo.jpg"))
{
doc.Pages[1].AddWatermark(imageWatermark);
}
doc.Save();
}