c# 如何实现图片压缩

一般在web应用中，对客户端提交上来的图片肯定需要进行压缩的。尤其是比较大的图片，如果不经过压缩会导致页面变的很大，打开速度比较慢，当然了如果是需要高质量的图片也得需要生产缩略图。

下面贴出我自己琢磨的图片压缩算法，首先这个是未经优化的简单实现：

代码如下:

        public static System.Drawing.Image GetImageThumb(System.Drawing.Image sourceImg, int width, int height)

        {

            System.Drawing.Image targetImg = new System.Drawing.Bitmap(width, height);

            using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(targetImg))

            {

                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

                g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;

                g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;

                g.DrawImage(sourceImg, new System.Drawing.Rectangle(0, 0, width, height), new System.Drawing.Rectangle(0, 0, sourceImg.Width, sourceImg.Height), System.Drawing.GraphicsUnit.Pixel);

                g.Dispose();

            }

            return targetImg;

        }

这个方法比较简单，用到的是高质量压缩。经过这个方法压缩后，200K的图片只能压缩到160k左右。经过改写代码实现了如下的方法：

代码如下:

        public static bool GetPicThumbnail(string sFile, string outPath, int flag)

        {

            System.Drawing.Image iSource = System.Drawing.Image.FromFile(sFile);

            ImageFormat tFormat = iSource.RawFormat;

            //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)

                {

                    iSource.Save(outPath, jpegICIinfo, ep);//dFile是压缩后的新路径 

                }

                else

                {

                    iSource.Save(outPath, tFormat);

                }

                return true;

            }

            catch

            {

                return false;

            }

            finally

            {

                iSource.Dispose();

                iSource.Dispose();

            }

        }

以上就是c# 如何实现图片压缩的详细内容，更多关于c# 图片压缩的资料请关注脚本之家其它相关文章！

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