C#: 图片压缩

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/yenange/article/details/89306473

using System;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace ImgCompress
{
    class Program
    {
        static void Main(string[] args)
        {
            string path = "1.png";                  // debug->bin 下必须有 1.png 这个文件
            string destFile = "compress\\1.png";    // debug->bin 下必须有 compress 这个文件夹

            Stopwatch sw = Stopwatch.StartNew();
            Bitmap srcBitMap = (Bitmap)Bitmap.FromFile(path, false);
            Compress(srcBitMap, destFile, 50);
            Console.WriteLine(sw.ElapsedMilliseconds);

            Console.Read();
        }

        private static ImageCodecInfo GetEncoderInfo(String mimeType)
        {
            int j;
            ImageCodecInfo[] encoders;
            encoders = ImageCodecInfo.GetImageEncoders();
            for (j = 0; j < encoders.Length; ++j)
            {
                if (encoders[j].MimeType == mimeType)
                    return encoders[j];
            }
            return null;
        }

        /// <summary>
        /// 图片压缩(降低质量以减小文件的大小)
        /// </summary>
        /// <param name="srcBitmap">传入的Bitmap对象</param>
        /// <param name="destStream">压缩后的Stream对象</param>
        /// <param name="level">压缩等级，0到100，0 最差质量，100 最佳</param>
        public static void Compress(Bitmap srcBitmap, Stream destStream, long level)
        {
            ImageCodecInfo myImageCodecInfo;
            System.Drawing.Imaging.Encoder myEncoder;
            EncoderParameter myEncoderParameter;
            EncoderParameters myEncoderParameters;

            // Get an ImageCodecInfo object that represents the JPEG codec.
            myImageCodecInfo = GetEncoderInfo("image/jpeg");

            // Create an Encoder object based on the GUID

            // for the Quality parameter category.
            myEncoder = System.Drawing.Imaging.Encoder.Quality;

            // Create an EncoderParameters object.
            // An EncoderParameters object has an array of EncoderParameter
            // objects. In this case, there is only one

            // EncoderParameter object in the array.
            myEncoderParameters = new EncoderParameters(1);

            // Save the bitmap as a JPEG file with 给定的 quality level
            myEncoderParameter = new EncoderParameter(myEncoder, level);
            myEncoderParameters.Param[0] = myEncoderParameter;
            srcBitmap.Save(destStream, myImageCodecInfo, myEncoderParameters);
        }

        /// <summary>
        /// 图片压缩(降低质量以减小文件的大小)
        /// </summary>
        /// <param name="srcBitMap">传入的Bitmap对象</param>
        /// <param name="destFile">压缩后的图片保存路径</param>
        /// <param name="level">压缩等级，0到100，0 最差质量，100 最佳</param>
        public static void Compress(Bitmap srcBitMap, string destFile, long level)
        {
            Stream s = new FileStream(destFile, FileMode.Create);
            Compress(srcBitMap, s, level);
            s.Close();
        }
    }
}