First, I’ll post the code I wrote, and then explain the issues at the end:
/// <summary>
/// 为pdf添加水印
/// </summary>
/// <param name="DocuementFileName">文档名称</param>
/// <param name="Save…...Drawing.Color WaterMarkFontColor, string...TempTextState = new TextState { Font = FontRepository.FindFont(WaterMarkFontName)...