c# 无损高质量压缩图片代码

来源：互联网发布：信考软件编辑：程序博客网时间：2024/05/18 00:10
        /// 无损压缩图片          /// <param name="sFile">原图片</param>          /// <param name="dFile">压缩后保存位置</param>          /// <param name="dHeight">高度</param>          /// <param name="dWidth"></param>          /// <param name="flag">压缩质量(数字越小压缩率越高) 1-100</param>          /// <returns></returns>          public static bool GetPicThumbnail(string sFile, string dFile, int dHeight, int dWidth, int flag)        {            System.Drawing.Image iSource = System.Drawing.Image.FromFile(sFile);            ImageFormat tFormat = iSource.RawFormat;            int sW = 0, sH = 0;            //按比例缩放            Size tem_size = new Size(iSource.Width, iSource.Height);            if (tem_size.Width > dHeight || tem_size.Width > dWidth)            {                if ((tem_size.Width * dHeight) > (tem_size.Width * dWidth))                {                    sW = dWidth;                    sH = (dWidth * tem_size.Height) / tem_size.Width;                }                else                {                    sH = dHeight;                    sW = (tem_size.Width * dHeight) / tem_size.Height;                }            }            else            {                sW = tem_size.Width;                sH = tem_size.Height;            }            Bitmap ob = new Bitmap(dWidth, dHeight);            Graphics g = Graphics.FromImage(ob);            g.Clear(Color.WhiteSmoke);            g.CompositingQuality = CompositingQuality.HighQuality;            g.SmoothingMode = SmoothingMode.HighQuality;            g.InterpolationMode = InterpolationMode.HighQualityBicubic;            g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel);            g.Dispose();            //以下代码为保存图片时，设置压缩质量              EncoderParameters ep = new EncoderParameters();            long[] qy = new long[1];            qy[0] = flag;//设置压缩的比例1-100              EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);            ep.Param[0] = eParam;            try            {                ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();                ImageCodecInfo jpegICIinfo = null;                for (int x = 0; x < arrayICI.Length; x++)                {                    if (arrayICI[x].FormatDescription.Equals("JPEG"))                    {                        jpegICIinfo = arrayICI[x];                        break;                    }                }                if (jpegICIinfo != null)                {                    ob.Save(dFile, jpegICIinfo, ep);//dFile是压缩后的新路径                  }                else                {                    ob.Save(dFile, tFormat);                }                return true;            }            catch            {                return false;            }            finally            {                iSource.Dispose();                ob.Dispose();            }        }
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