C#使用iTextSharp给PDF文件加水印

给PDF添加水印，可以用iTextSharp。

步骤1:下载iTextSharp

步骤2:在项目中添加引用itextsharp.dll

步骤3:在程序中使用iTextSharp.text.pdf

using iTextSharp.text.pdf;

步骤5：详细实现

        public static bool AddWatermark(string inputfilepath, string outputfilepath, string ModelPicName, float top, float left)

        {

            PdfReader pdfReader = null;

            PdfStamper pdfStamper = null;

            try

            {

                pdfReader = new PdfReader(inputfilepath);

                int numberOfPages = pdfReader.NumberOfPages;

                iTextSharp.text.Rectangle pagesize = pdfReader.GetPageSize();

                pdfStamper = new PdfStamper(pdfReader, new FileStream(outputfilepath, FileMode.Create));

                PdfContentByte waterMarkContent;

                iTextSharp.text.Image image = iTextSharp.text.Image.GetInstance(ModelPicName);

                image.GrayFill = ;//透明度，灰色填充

                float waterLeft = pagesize.Width - image.Width - left;

                float waterTop = pagesize.Height - image.Height - top;

                image.SetAbsolutePosition(waterLeft, waterTop);

                for (int i = ; i <= numberOfPages; i++)

                {

                    waterMarkContent = pdfStamper.GetOverContent(i);//.GetUnderContent(i);

                    waterMarkContent.AddImage(image);

                }

                return true;

            }

            catch (Exception ex)

            {

                ex.Message.Trim();

                return false;

            }

            finally

            {

                if (pdfStamper != null)

                    pdfStamper.Close();

                if (pdfReader != null)

                    pdfReader.Close();

            }

        }