Asp.Net 高清图片缩略图生成

来源：互联网发布：不想找女朋友知乎编辑：程序博客网时间：2024/05/16 19:14

核心代码：

/// <summary>        /// 图片上传 生成缩略图        /// </summary>        /// <param name="files">文件上传控件</param>        /// <param name="path">文件夹名称</param>        /// <param name="fname">文件名称</param>        /// <param name="w">缩略图宽度</param>        /// <param name="h">缩略图高度</param>        public static void UploadImageThumbs(HttpPostedFile files, string filePath, string fname, int w, int h)        {            if (UtilsFile.IsOrNoFileUp(files) && fname.Equals(String.Empty) == false)            {                UtilsFile.DirectorysCreate(filePath);                Image image = Image.FromStream(files.InputStream, true);                //等比例缩放                if (w > 0 && h > 0)                {                    if (image.Width > image.Height)                    {                        if (image.Width > w)                            h = (int)(image.Height * ((decimal)w / image.Width));                        else                        {                            h = image.Height;                            w = image.Width;                        }                    }                    else                    {                        if (image.Height > h)                            w = (int)(image.Width * ((decimal)h / image.Height));                        else                        {                            h = image.Height;                            w = image.Width;                        }                    }                }                else if (w > 0 && h == 0)                {                    if (image.Width < w)                        w = image.Width;                    h = (int)(image.Height * ((decimal)w / image.Width));                }                else if (w == 0 && h > 0)                {                    if (image.Height < h)                        h = image.Height;                    w = (int)(image.Width * ((decimal)h / image.Height));                }                else                {                    w = image.Width;                    h = image.Height;                }                Bitmap ret = new Bitmap(w, h);                using (Graphics g = Graphics.FromImage(ret))                {                    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;                    g.FillRectangle(Brushes.White, 0, 0, w, h);                    g.DrawImage(image, 0, 0, w, h);                    EncoderParameters parms = new EncoderParameters();                    long[] quality = new long[1];                    quality[0] = 80;                    EncoderParameter parm = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);                    parms.Param[0] = parm;                    ImageCodecInfo[] arr = ImageCodecInfo.GetImageEncoders();                    ImageCodecInfo ar = null;                    for (int x = 0; x < arr.Length; x++)                    {                        if (arr[x].FormatDescription.Equals("JPEG"))                        {                            ar = arr[x];                            break;                        }                    }                    ret.Save(filePath + fname, ar, parms);                    ret.Dispose();                    image.Dispose();                }            }        }

总结：以上生成缩略图代码，效果是比较好的，就是有时候红色的点会失真，比较无解。不过这问题基本可以忽略不计。较真的朋友，如有较好的生成代码，可以共享。

原谅转载:http://www.dyxue.com/tech/id2498.html

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