ASP.NET 上传图片添加文字、Logo水印

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D; 

/// <summary>
/// Helper 的摘要说明
/// </summary>
public class Helper
{
    public class UpLoadHelper
    {
        #region 添加文字水印
        /// <summary>         
        /// 添加文字水印         
        /// </summary>         
        /// <param name="text">水印文字</param>         
        /// <param name="file">图片文件</param>         
        public static void AttachText(string text, string file)
        {
            if (string.IsNullOrEmpty(text))
            {
                return;
            }
            if (!File.Exists(file))
            {
                return;
            }
            FileInfo oFile = new FileInfo(file);
            string strTempFile = Path.Combine(oFile.DirectoryName, Guid.NewGuid().ToString() + oFile.Extension);
            oFile.CopyTo(strTempFile);
            Image img = Image.FromFile(strTempFile);
            ImageFormat thisFormat = img.RawFormat;
            int nHeight = img.Height;
            int nWidth = img.Width;
            Bitmap outBmp = new Bitmap(nWidth, nHeight);
            Graphics g = Graphics.FromImage(outBmp);
            g.Clear(Color.White);
            // 设置画布的描绘质量        
            g.CompositingQuality = CompositingQuality.HighQuality;
            g.SmoothingMode = SmoothingMode.HighQuality;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.DrawImage(img, new Rectangle(0, 0, nWidth, nHeight), 0, 0, nWidth, nHeight, GraphicsUnit.Pixel);
            int[] sizes = new int[] { 16, 14, 12, 10, 8, 6, 4 };
            Font crFont = null;
            SizeF crSize = new SizeF();
            //通过循环这个数组，来选用不同的字体大小   
            //如果它的大小小于图像的宽度，就选用这个大小的字体     
            for (int i = 0; i < 7; i++)
            {
                //设置字体，这里是用arial，黑体       
                crFont = new Font("arial", sizes[i], FontStyle.Bold);
                //Measure the Copyright string in this Font             
                crSize = g.MeasureString(text, crFont);
                if ((ushort)crSize.Width < (ushort)nWidth)
                { break; }
            }
            //因为图片的高度可能不尽相同, 所以定义了       
            //从图片底部算起预留了5%的空间     
            int yPixlesFromBottom = (int)(nHeight * .08);
            //现在使用版权信息字符串的高度来确定要绘制的图像的字符串的y坐标    
            float yPosFromBottom = ((nHeight - yPixlesFromBottom) - (crSize.Height / 2));
            //计算x坐标          
            float xCenterOfImg = (nWidth / 2);
            //把文本布局设置为居中          
            StringFormat StrFormat = new StringFormat();

            StrFormat.Alignment = StringAlignment.Center;
            //通过Brush来设置黑色半透明      
            SolidBrush semiTransBrush2 = new SolidBrush(Color.FromArgb(153, 0, 0, 0));
            //绘制版权字符串           
            g.DrawString(text,             //版权字符串文本            
                crFont,                             //字体           
                semiTransBrush2,                           //Brush        
                new PointF(xCenterOfImg + 1, yPosFromBottom + 1),  //位置     
                StrFormat);              //设置成白色半透明          
            SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(153, 255, 255, 255));
            //第二次绘制版权字符串来创建阴影效果           
            //记住移动文本的位置1像素           
            g.DrawString(text,                 //版权文本     
                crFont,                                   //字体 
                semiTransBrush,                           //Brush    
                new PointF(xCenterOfImg, yPosFromBottom),  //位置     
                StrFormat);
            g.Dispose();              // 以下代码为保存图片时，设置压缩质量         
            EncoderParameters encoderParams = new EncoderParameters();
            long[] quality = new long[1];
            quality[0] = 100;
            EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
            encoderParams.Param[0] = encoderParam;              //获得包含有关内置图像编码解码器的信息的ImageCodecInfo 对象。
            ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();
            ImageCodecInfo jpegICI = null;
            for (int x = 0; x < arrayICI.Length; x++)
            {
                if (arrayICI[x].FormatDescription.Equals("JPEG"))
                {
                    jpegICI = arrayICI[x];//设置JPEG编码          
                    break;
                }
            } if (jpegICI != null)
            { outBmp.Save(file, jpegICI, encoderParams); }
            else { outBmp.Save(file, thisFormat); }
            img.Dispose();
            outBmp.Dispose();
            File.Delete(strTempFile);
        }
        #endregion
    }
}

页面调用：Helper.UpLoadHelper.AttachText("水印文字", FileUpload1.PostedFile.FileName);

2,

/// <summary>
        /// 增加图片文字水印
        /// </summary>
        /// <param name="filename">文件名</param>
        /// <param name="watermarkText">水印文字</param>
        /// <param name="watermarkStatus">图片水印位置</param>
        /// <param name="quality">附加图片质量，1是 0不是</param>
        public static void AddImageSignText(Image img, string filename, string watermarkText, int watermarkStatus, int quality, string fontname, int fontsize)
        {
            //System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(img);
            //    .FromFile(filename);
            Graphics g = Graphics.FromImage(img);
            Font drawFont = new Font(fontname, fontsize, FontStyle.Regular, GraphicsUnit.Pixel);
            SizeF crSize;
            crSize = g.MeasureString(watermarkText, drawFont);

            float xpos = 0;
            float ypos = 0;

            switch (watermarkStatus)
            {
                case 1:
                    xpos = (float)img.Width * (float).01;
                    ypos = (float)img.Height * (float).01;
                    break;
                case 2:
                    xpos = ((float)img.Width * (float).50) - (crSize.Width / 2);
                    ypos = (float)img.Height * (float).01;
                    break;
                case 3:
                    xpos = ((float)img.Width * (float).99) - crSize.Width;
                    ypos = (float)img.Height * (float).01;
                    break;
                case 4:
                    xpos = (float)img.Width * (float).01;
                    ypos = ((float)img.Height * (float).50) - (crSize.Height / 2);
                    break;
                case 5:
                    xpos = ((float)img.Width * (float).50) - (crSize.Width / 2);
                    ypos = ((float)img.Height * (float).50) - (crSize.Height / 2);
                    break;
                case 6:
                    xpos = ((float)img.Width * (float).99) - crSize.Width;
                    ypos = ((float)img.Height * (float).50) - (crSize.Height / 2);
                    break;
                case 7:
                    xpos = (float)img.Width * (float).01;
                    ypos = ((float)img.Height * (float).99) - crSize.Height;
                    break;
                case 8:
                    xpos = ((float)img.Width * (float).50) - (crSize.Width / 2);
                    ypos = ((float)img.Height * (float).99) - crSize.Height;
                    break;
                case 9:
                    xpos = ((float)img.Width * (float).99) - crSize.Width;
                    ypos = ((float)img.Height * (float).99) - crSize.Height;
                    break;
            }

            //            System.Drawing.StringFormat StrFormat = new System.Drawing.StringFormat();
            //            StrFormat.Alignment = System.Drawing.StringAlignment.Center;
            //
            //            g.DrawString(watermarkText, drawFont, new System.Drawing.SolidBrush(System.Drawing.Color.White), xpos + 1, ypos + 1, StrFormat);
            //            g.DrawString(watermarkText, drawFont, new System.Drawing.SolidBrush(System.Drawing.Color.Black), xpos, ypos, StrFormat);
            g.DrawString(watermarkText, drawFont, new SolidBrush(Color.White), xpos + 1, ypos + 1);
            g.DrawString(watermarkText, drawFont, new SolidBrush(Color.Black), xpos, ypos);

            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
            ImageCodecInfo ici = null;
            foreach (ImageCodecInfo codec in codecs)
            {
                if (codec.MimeType.IndexOf("jpeg") > -1)
                {
                    ici = codec;
                }
            }
            EncoderParameters encoderParams = new EncoderParameters();
            long[] qualityParam = new long[1];
            if (quality < 0 || quality > 100)
            {
                quality = 80;
            }
            qualityParam[0] = quality;

            EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityParam);
            encoderParams.Param[0] = encoderParam;

            if (ici != null)
            {
                img.Save(filename, ici, encoderParams);
            }
            else
            {
                img.Save(filename);
            }
            g.Dispose();
            //bmp.Dispose();
            img.Dispose();
        }

页面调用：、
Image img = Image.FromStream(this.FileUpload1.PostedFile.InputStream);
Helper.UpLoadHelper.AddImageSignText(img, FileUpload1.PostedFile.FileName, "水印文字", 1, 100, "宋体", 20);

3，加上LOGO图片水印

        /// <summary>
        /// 加上logo图片水印
        /// </summary>
        /// <param name="FilePath">源图片地址</param>
        /// <param name="SavePath">图片保存路径</param>
        public static void AddWaterMark(string FilePath, string SavePath,string logoPath)
        {
            Bitmap bitmap = new Bitmap(FilePath);
            Graphics g = Graphics.FromImage(bitmap);

            System.Drawing.Image logo = System.Drawing.Image.FromFile(logoPath);//加载logo图片
            if (bitmap.Width < logo.Width || bitmap.Height <= logo.Height)
                return;

            //下面定义一个矩形区域，以后在这个矩形里画上透明背景和白色字体
            float rectWidth = (float)logo.Width;
            float rectHeight = (float)logo.Height;
            float rectX = bitmap.Width - rectWidth;
            float rectY = bitmap.Height - rectHeight;
            //声明矩形域
            RectangleF textArea = new RectangleF(rectX, rectY, rectWidth, rectHeight);
            g.DrawImage(logo, textArea);
            MemoryStream ms = new MemoryStream();
            //保存为Jpg类型
            bitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            g.Dispose();
            bitmap.Dispose();
            logo.Dispose();

            FileStream fs = new FileStream(SavePath, FileMode.OpenOrCreate);
            fs.Write(ms.ToArray(), 0, ms.ToArray().Length);
            fs.Close();
        }

页面调用：
Helper.UpLoadHelper.AddWaterMark(FileUpload1.PostedFile.FileName, Server.MapPath("~/images/aa.jpg"), FileUpload2.PostedFile.FileName);