C#图片处理：实现文字水印效果

 protected void Button2_Click(object sender, EventArgs e)
    {
        
        if (UploadFile.PostedFile.FileName.Trim() != "")
        {
            //上传文件
            string extension = Path.GetExtension(UploadFile.PostedFile.FileName).ToUpper();
            string fileName = DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString() + DateTime.Now.Day.ToString() + DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString();
            string path = Server.MapPath(".") + "/UploadFile/" + fileName + extension;
            UploadFile.PostedFile.SaveAs(path);

            //加文字水印，注意，这里的代码和以下加图片水印的代码不能共存
            System.Drawing.Image image = System.Drawing.Image.FromFile(path);
            Graphics g = Graphics.FromImage(image);
            g.DrawImage(image, 0, 0, image.Width, image.Height);
            Font f = new Font("Verdana", 32);
            Brush b = new SolidBrush(Color.FromArgb(100,255,255,255)); //FromArgb第一个参数表示透明度，0-255，后面三个颜色。
            string addText = AddText.Text.Trim();

            g.DrawString(addText, f, b, 10, 10);
            g.Dispose();

           // //加图片水印
           // System.Drawing.Image image = System.Drawing.Image.FromFile(path);
           // Bitmap b = new Bitmap(image.Width, image.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
           // Graphics g = Graphics.FromImage(image);
           //// g.Clear(Color.White);
           // g.DrawImage(image, 0, 0, image.Width, image.Height);

           // System.Drawing.Image watermark = new Bitmap(System.Drawing.Image.FromFile(Server.MapPath(".") + "/UpLoadFile/message.jpg"));