给图片批量添加水印

效果与商城上的效果类似

  protected void Add_Click(object sender, EventArgs e)
        {
            DirectoryInfo theFolder = new DirectoryInfo(Request.PhysicalApplicationPath + "Images\Product");
            //遍历文件夹
            foreach (DirectoryInfo NextFolder in theFolder.GetDirectories())
            {
                foreach (FileInfo NextFile in NextFolder.GetFiles())
                {
                    if (NextFile.Name.Contains("SY800SY"))
                    {
                        File.Delete(NextFile.FullName);
                    }
                    else if (!NextFile.Name.Contains("SY.") && !NextFile.Name.Contains("SY800."))
                    {
                        if (!NextFile.Name.Contains("47-47_") && !NextFile.Name.Contains("50-50_") &&
                            !NextFile.Name.Contains("80-80_") && !NextFile.Name.Contains("100-100_") &&
                            !NextFile.Name.Contains("120-120_") && !NextFile.Name.Contains("140-140_") &&
                            !NextFile.Name.Contains("160-160_") && !NextFile.Name.Contains("380-380_"))
                        {
                            MarkWater(NextFile.FullName, Request.PhysicalApplicationPath + "images\" + "logo-back.png");
                        }
                    }
                }

            }
        }

给图片添加水印的方法

 /// <summary>
        /// 给图片添加水印
        /// </summary>
        /// <param name="filePath">原图片地址</param>
        /// <param name="waterFile">水印图片地址</param>
        private void MarkWater(string filePath, string waterFile)
        {
            int i = filePath.LastIndexOf(".");
            string ex = filePath.Substring(i, filePath.Length - i);
            if (string.Compare(ex, ".gif", true) == 0)
            {
                return;
            }
            int newp = filePath.LastIndexOf(".");
            string newpo = filePath.Substring(0, newp);
            string newpolast = filePath.Substring(newp + 1);
            string newlastimg = newpo + "SY800" + "." + newpolast;
            BitmapHelper.MakeThumbnail(filePath, newlastimg, 800, 800, "DB", "JPG");
            string ModifyImagePath = newlastimg;
            int lucencyPercent = 25;
            System.Drawing.Image modifyImage = null;
            System.Drawing.Image drawedImage = null;
            Graphics g = null;
            try
            {
                modifyImage = System.Drawing.Image.FromFile(ModifyImagePath, true);
                drawedImage = System.Drawing.Image.FromFile(waterFile, true);
                g = Graphics.FromImage(modifyImage);
                int x = (modifyImage.Width - drawedImage.Width) / 2;
                int y = (modifyImage.Height - drawedImage.Height) / 2;
                float[][] matrixItems =//控制水印图片的透明度
                {
                    new float[] {1, 0, 0, 0, 0},
                    new float[] {0, 1, 0, 0, 0},
                    new float[] {0, 0, 1, 0, 0},
                    new float[] {0, 0, 0, (float) lucencyPercent/100f, 0}, 
                    new float[] {0, 0, 0, 0, 1}
                };

                ColorMatrix colorMatrix = new ColorMatrix(matrixItems);
                ImageAttributes imgAttr = new ImageAttributes();
                imgAttr.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
                g.DrawImage(drawedImage, new Rectangle(x, y, drawedImage.Width, drawedImage.Height), 10, 10,
                    drawedImage.Width, drawedImage.Height, GraphicsUnit.Pixel, imgAttr);
                string[] allowImageType = { ".jpg", ".gif", ".png", ".bmp", ".tiff", ".wmf", ".ico" };
                FileInfo fi = new FileInfo(ModifyImagePath);
                ImageFormat imageType = ImageFormat.Gif;
                switch (fi.Extension.ToLower())
                {
                    case ".jpg":
                        imageType = ImageFormat.Jpeg;
                        break;
                    case ".gif":
                        imageType = ImageFormat.Gif;
                        break;
                    case ".png":
                        imageType = ImageFormat.Png;
                        break;
                    case ".bmp":
                        imageType = ImageFormat.Bmp;
                        break;
                    case ".tif":
                        imageType = ImageFormat.Tiff;
                        break;
                    case ".wmf":
                        imageType = ImageFormat.Wmf;
                        break;
                    case ".ico":
                        imageType = ImageFormat.Icon;
                        break;
                    default:
                        break;
                }
                MemoryStream ms = new MemoryStream();
                modifyImage.Save(ms, imageType);
                byte[] imgData = ms.ToArray();
                modifyImage.Dispose();
                drawedImage.Dispose();
                g.Dispose();
                FileStream fs = null;
                fs = new FileStream(ModifyImagePath.Replace("SY800.", "SY."), FileMode.Create, FileAccess.Write);
                if (fs != null)
                {
                    fs.Write(imgData, 0, imgData.Length);
                    fs.Close();
                }
            }
            finally
            {
                try
                {
                    drawedImage.Dispose();
                    modifyImage.Dispose();
                    g.Dispose();
                }
                catch
                {
                }
            }
        }

用到的一个生成缩略图的类

public class BitmapHelper
    {
        /// <summary>
        /// 生成缩略图
        /// </summary>
        /// <param name="originalImagePath">源图路径（物理路径）</param>
        /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
        /// <param name="width">缩略图宽度</param>
        /// <param name="height">缩略图高度</param>
        /// <param name="mode">生成缩略图的方式</param>
        /// <param name="type">缩略图的图片类型</param> 
        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode, string type)
        {
            Image originalImage = Image.FromFile(originalImagePath);

            int towidth = width;
            int toheight = height;

            int x = 0;
            int y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;

            switch (mode)
            {
                case "HW"://指定高宽缩放（可能变形） 
                    break;
                case "W"://指定宽，高按比例 
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高，宽按比例
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高宽裁减（不变形） 
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                case "DB"://等比缩放（不变形，如果高大按高，宽大按宽缩放） 
                    if ((double)originalImage.Width / (double)towidth < (double)originalImage.Height / (double)toheight)
                    {
                        toheight = height;
                        towidth = originalImage.Width * height / originalImage.Height;
                    }
                    else
                    {
                        towidth = width;
                        toheight = originalImage.Height * width / originalImage.Width;
                    }
                    break;
                default:
                    break;
            }

            //新建一个bmp图片
            Image bitmap = new Bitmap(towidth, toheight);

            //新建一个画板
            Graphics g = Graphics.FromImage(bitmap);

            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            //清空画布并以透明背景色填充
            g.Clear(Color.Transparent);

            //在指定位置并且按指定大小绘制原图片的指定部分
            g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
            new Rectangle(x, y, ow, oh),
            GraphicsUnit.Pixel);

            try
            {
                //保存缩略图
                if (type.ToUpper() == "JPG")
                {
                    bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
                }
                if (type.ToUpper() == "BMP")
                {
                    bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Bmp);
                }
                if (type.ToUpper() == "GIF")
                {
                    bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Gif);
                }
                if (type.ToUpper() == "PNG")
                {
                    bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Png);
                }
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }
    }

基本上就Ok 了 自己记录的文章没有仔细排版 也没有多少文字说明