.net上传图片的处理类库（缩略图、水印）_.net6 图片处理库

  public static class ImageHelp
    {
        #region 生成缩略图
        /// <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
        /// <code>HW:指定高宽缩放（可能变形）</code>
        /// <code>W:指定宽，高按比例  </code>
        /// <code>H:指定高，宽按比例</code>
        /// <code>CUT:指定高宽裁减（不变形） </code>
        /// <code>FILL:填充</code>
        /// </param>    
        public static bool LocalImage2Thumbs(string originalImagePath, string thumbnailPath, int width, int height, string mode)
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);
            Image2Thumbs(originalImage, thumbnailPath, width, height, mode);
            originalImage.Dispose();
            return true;
        }
        /// <summary>
        /// 生成远程图片的缩略图
        /// </summary>
        /// <param name="remoteImageUrl"></param>
        /// <param name="thumbnailPath"></param>
        /// <param name="width"></param>
        /// <param name="height"></param>
        /// <param name="mode"></param>
        /// <returns></returns>
        public static bool RemoteImage2Thumbs(string remoteImageUrl, string thumbnailPath, int width, int height, string mode)
        {
            try
            {
                WebRequest request = WebRequest.Create(remoteImageUrl);
                request.Timeout = 20000;
                Stream stream = request.GetResponse().GetResponseStream();
                System.Drawing.Image originalImage = System.Drawing.Image.FromStream(stream);
                Image2Thumbs(originalImage, thumbnailPath, width, height, mode);
                originalImage.Dispose();
                return true;
            }
            catch
            {
                return false;
            }
        }
 
        /// <summary>
        /// 生成缩略图
        /// </summary>
        /// <param name="originalImage">源图</param>
        /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
        /// <param name="photoWidth">最终缩略图宽度</param>
        /// <param name="height">最终缩略图高度</param>
        /// <param name="mode">生成缩略图的方式
        /// <code>HW:指定高宽缩放（可能变形）</code>
        /// <code>W:指定宽，高按比例  </code>
        /// <code>H:指定高，宽按比例</code>
        /// <code>CUT:指定高宽裁减（不变形） </code>
        /// <code>FILL:填充</code>
        /// </param> 
        public static void Image2Thumbs(System.Drawing.Image originalImage, string thumbnailPath, int photoWidth, int photoHeight, string mode)
        {
            #region 开始画图
            int lastPhotoWidth = photoWidth;//最后缩略图的宽度
            int lastPhotoHeight = photoHeight;//最后缩略图的高度
 
            int toWidth = photoWidth;//原图片被压缩的宽度
            int toHeight = photoHeight;//原图片被压缩的高度
 
            int x = 0;
            int y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;
 
            int bg_x = 0;
            int bg_y = 0;
            switch (mode.ToUpper())
            {
                case "FILL"://压缩填充至指定区域                
                    toHeight = photoHeight;
                    toWidth = toHeight * ow / oh;
                    if (toWidth > photoWidth)
                    {
                        toHeight = toHeight * photoWidth / toWidth;
                        toWidth = photoWidth;
                    }
                    bg_x = (photoWidth - toWidth) / 2;
                    bg_y = (photoHeight - toHeight) / 2;
                    break;
                case "HW"://指定高宽缩放（可能变形）                
                    break;
                case "W"://指定宽，高按比例                    
                    toHeight = lastPhotoHeight = originalImage.Height * photoWidth / originalImage.Width;
                    break;
                case "H"://指定高，宽按比例
                    toWidth = lastPhotoWidth = originalImage.Width * photoHeight / originalImage.Height;
                    break;
                case "CUT"://指定高宽裁减（不变形）                
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)lastPhotoWidth / (double)lastPhotoHeight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * lastPhotoWidth / lastPhotoHeight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * photoHeight / lastPhotoWidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                default:
                    break;
            }
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(lastPhotoWidth, lastPhotoHeight);//新建一个bmp图片
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);//新建一个画板
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;//设置高质量插值法
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
            g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            g.Clear(System.Drawing.Color.White);//白色
            g.DrawImage(originalImage, new System.Drawing.Rectangle(bg_x, bg_y, toWidth, toHeight),//在指定位置并且按指定大小绘制原图片的指定部分
                new System.Drawing.Rectangle(x, y, ow, oh),
                System.Drawing.GraphicsUnit.Pixel);
            try
            {
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
 
                bitmap.Dispose();
                g.Dispose();
            }
            #endregion
        }
        #endregion
 
        /// <summary>
        /// 切割后生成缩略图
        /// </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="toW">缩略图最终宽度</param>
        /// <param name="toH">缩略图最终高度</param>
        /// <param name="X">X坐标（zoom为1时）</param>
        /// <param name="Y">Y坐标（zoom为1时）</param>
        /// <param name="W">选择区域宽（zoom为1时）</param>
        /// <param name="H">选择区域高（zoom为1时）</param>
        public static void MakeMyThumbs(string originalImagePath, string thumbnailPath, int toW, int toH, int X, int Y, int W, int H)
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);
            int towidth = toW;
            int toheight = toH;
            int x = X;
            int y = Y;
            int ow = W;
            int oh = H;
            //新建一个bmp图片
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
            //新建一个画板
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;//设置高质量插值法
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
            g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            //清空画布并以透明背景色填充
            g.Clear(System.Drawing.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 System.Drawing.Rectangle(0, 0, towidth, toheight),
            new System.Drawing.Rectangle(x, y, ow, oh),
            System.Drawing.GraphicsUnit.Pixel);
            try
            {
                //以jpg格式保存缩略图
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }
 
        #region 在图片上增加文字水印
        /// <summary>
        /// 在图片上增加文字水印
        /// </summary>
        /// <param name="Path">原服务器图片路径</param>
        /// <param name="Path_sy">生成的带文字水印的图片路径</param>
        /// <param name="addText">水印文字</param>
        public static void AddWater(string Path, string Path_sy, string addText)
        {
            System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
            g.DrawImage(image, 0, 0, image.Width, image.Height);
            System.Drawing.Font f = new System.Drawing.Font("Verdana", 60);
            System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.Green);
 
            g.DrawString(addText, f, b, 35, 35);
            g.Dispose();
 
            image.Save(Path_sy);
            image.Dispose();
        }
        #endregion
 
        #region 在图片上生成图片水印
        /// <summary>
        /// 加图片水印
        /// </summary>
        /// <param name="filename">文件名</param>
        /// <param name="watermarkFilename">水印文件名</param>
        /// <param name="watermarkStatus">图片水印位置:0=不使用 1=左上 2=中上 3=右上 4=左中 ... 9=右下</param>
        /// <param name="quality">是否是高质量图片 取值范围0--100</param> 
        /// <param name="watermarkTransparency">图片水印透明度 取值范围1--10 (10为不透明)</param>
 
        public static void AddImageSignPic(string Path, string filename, string watermarkFilename, int watermarkStatus, int quality, int watermarkTransparency)
        {
            System.Drawing.Image img = System.Drawing.Image.FromFile(Path);
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(img);
 
            //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;
            System.Drawing.Image watermark = new System.Drawing.Bitmap(watermarkFilename);
 
            if (watermark.Height >= img.Height || watermark.Width >= img.Width)
            {
                return;
            }
 
            System.Drawing.Imaging.ImageAttributes imageAttributes = new System.Drawing.Imaging.ImageAttributes();
            System.Drawing.Imaging.ColorMap colorMap = new System.Drawing.Imaging.ColorMap();
 
            colorMap.OldColor = System.Drawing.Color.FromArgb(255, 0, 255, 0);
            colorMap.NewColor = System.Drawing.Color.FromArgb(0, 0, 0, 0);
            System.Drawing.Imaging.ColorMap[] remapTable = { colorMap };
 
            imageAttributes.SetRemapTable(remapTable, System.Drawing.Imaging.ColorAdjustType.Bitmap);
 
            float transparency = 0.5F;
            if (watermarkTransparency >= 1 && watermarkTransparency <= 10)
            {
                transparency = (watermarkTransparency / 10.0F);
            }
 
            float[][] colorMatrixElements = {
                                                new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},
                                                new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},
                                                new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},
                                                new float[] {0.0f,  0.0f,  0.0f,  transparency, 0.0f},
                                                new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
                                            };
 
            System.Drawing.Imaging.ColorMatrix colorMatrix = new System.Drawing.Imaging.ColorMatrix(colorMatrixElements);
 
            imageAttributes.SetColorMatrix(colorMatrix, System.Drawing.Imaging.ColorMatrixFlag.Default, System.Drawing.Imaging.ColorAdjustType.Bitmap);
 
            int xpos = 0;
            int ypos = 0;
 
            switch (watermarkStatus)
            {
                case 1:
                    xpos = (int)(img.Width * (float).01);
                    ypos = (int)(img.Height * (float).01);
                    break;
                case 2:
                    xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
                    ypos = (int)(img.Height * (float).01);
                    break;
                case 3:
                    xpos = (int)((img.Width * (float).99) - (watermark.Width));
                    ypos = (int)(img.Height * (float).01);
                    break;
                case 4:
                    xpos = (int)(img.Width * (float).01);
                    ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
                    break;
                case 5:
                    xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
                    ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
                    break;
                case 6:
                    xpos = (int)((img.Width * (float).99) - (watermark.Width));
                    ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
                    break;
                case 7:
                    xpos = (int)(img.Width * (float).01);
                    ypos = (int)((img.Height * (float).99) - watermark.Height);
                    break;
                case 8:
                    xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
                    ypos = (int)((img.Height * (float).99) - watermark.Height);
                    break;
                case 9:
                    xpos = (int)((img.Width * (float).99) - (watermark.Width));
                    ypos = (int)((img.Height * (float).99) - watermark.Height);
                    break;
            }
 
            g.DrawImage(watermark, new System.Drawing.Rectangle(xpos, ypos, watermark.Width, watermark.Height), 0, 0, watermark.Width, watermark.Height, System.Drawing.GraphicsUnit.Pixel, imageAttributes);
 
            System.Drawing.Imaging.ImageCodecInfo[] codecs = System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders();
            System.Drawing.Imaging.ImageCodecInfo ici = null;
            foreach (System.Drawing.Imaging.ImageCodecInfo codec in codecs)
            {
                //if (codec.MimeType.IndexOf("jpeg") > -1)
                if (codec.MimeType.Contains("jpeg"))
                {
                    ici = codec;
                }
            }
            System.Drawing.Imaging.EncoderParameters encoderParams = new System.Drawing.Imaging.EncoderParameters();
            long[] qualityParam = new long[1];
            if (quality < 0 || quality > 100)
            {
                quality = 80;
            }
            qualityParam[0] = quality;
 
            System.Drawing.Imaging.EncoderParameter encoderParam = new System.Drawing.Imaging.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();
            img.Dispose();
            watermark.Dispose();
            imageAttributes.Dispose();
        }
 
        /// <summary>
        /// 在图片上生成图片水印
        /// </summary>
        /// <param name="Path">原服务器图片路径</param>
        /// <param name="Path_syp">生成的带图片水印的图片路径</param>
        /// <param name="Path_sypf">水印图片路径</param>
        public static void AddWaterPic(string Path, string Path_syp, string Path_sypf)
        {
            System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
            System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf);
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
            g.DrawImage(copyImage, new System.Drawing.Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, System.Drawing.GraphicsUnit.Pixel);
            g.Dispose();
 
            image.Save(Path_syp);
            image.Dispose();
        }
        #endregion
    }
 
    public class ChangePicToSave
    {
        private int width;
        private int height;
        private System.Drawing.Bitmap newpic, savepic;
        private float k1, k2;
 
        /// <summary>
        /// 构造函数
        /// </summary>
        public ChangePicToSave()
        {
        }
        /// <summary>
        /// 保存一张小图，一张大图，和一张原图
        /// </summary>
        /// <param name="TheImage">传入的图片对象</param>
        /// <param name="path">保存的文件名和路径</param>
        public void SaveThreePicture(object TheImage, string path)
        {
            string pic_larger;
            string pic_smaller;
            pic_larger = path.Substring(0, path.IndexOf("."));
            pic_larger += "_l.jpg";
            pic_smaller = path.Substring(0, path.IndexOf("."));
            pic_smaller += "_s.jpg";
 
            ChangePicToSave cp = new ChangePicToSave();
            cp.ChangePicToSaveMethod(TheImage, 200, 200, pic_smaller);
            cp.ChangePicToSaveMethod(TheImage, 800, 800, pic_larger);
        }
        /// <summary>
        /// 保存一张图片，并设定它的大小
        /// </summary>
        /// <param name="TheImage">传入的图片对象</param>
        /// <param name="TheWidth">图片宽的范围</param>
        /// <param name="TheHeight">图片长的范围</param>
        /// <param name="path">保存的文件名和路径</param>
        public void ChangePicToSaveMethod(object TheImage, int TheWidth, int TheHeight, string path)
        {
            newpic = new System.Drawing.Bitmap((System.Drawing.Image)TheImage);
            this.width = newpic.Width;
            this.height = newpic.Height;
 
            k1 = (float)width / (float)TheWidth;
            k2 = (float)height / (float)TheHeight;
            if (k1 > k2)
            {
                this.width = (int)(width / k1);
                this.height = (int)(height / k1);
            }
            else
            {
                this.width = (int)(width / k2);
                this.height = (int)(height / k2);
            }
            savepic = new System.Drawing.Bitmap(newpic, width, height);
            savepic.Save(@path);
        }
    }