IDocumentInfo

public interface IDocumentInfo

using (Watermarker watermarker = new Watermarker("D:\\input.pdf"))
{
    IDocumentInfo docInfo = watermarker.GetDocumentInfo();
    Console.WriteLine("Document size: {0}", docInfo.Size);
    Console.WriteLine("Document format: {0}", docInfo.FileType.FileFormat);
    Console.WriteLine("Document contains {0} pages", docInfo.PageCount);
}