C#实现图片压缩 – 清风亦平凡

有些时候会在博客中分享一些拍摄的照片，而这些拍摄照片的大小均在1.5M以上，随随便便分享点图片占用的存储空间就有点惊人。为了节省存储空间，避免尽早将剩余存储空间消耗完毕，所以就考虑压缩一下图片。这里来做下记录。


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

namespace ImageCompress
{
    class Program
    {
        static void Main(string[] args)
        {
            string path = $"{Path.Combine(Directory.GetCurrentDirectory(), "image")}";
            CompressionImageProcess.CompressionImage($"{Path.Combine(path, "IMG_20200308_161707.jpg")}",$"{Path.Combine(path, "compression")}",50);
            Console.WriteLine("OK");
        }
    }
    public class CompressionImageProcess
    {
        public static void CompressionImage(string imagePath, string targetfolder, long quality = 100)
        {
            if (!File.Exists(imagePath))
            {
                throw new FileNotFoundException();
            }
            if (!Directory.Exists(targetfolder))
            {
                Directory.CreateDirectory(targetfolder);
            }
            FileInfo fileInfo = new FileInfo(imagePath);
            string fileName = fileInfo.Name.Replace(fileInfo.Extension, "");
            string fileFullName = Path.Combine($"{targetfolder}", $"{fileName}{fileInfo.Extension}");

            var iamgeByte = CompressionImage(imagePath, quality);
            MemoryStream ms = new MemoryStream(iamgeByte);
            Image image = System.Drawing.Image.FromStream(ms);
            image.Save(fileFullName);
            ms?.Close();
            ms?.Dispose();
            image?.Dispose();
        }
        private static byte[] CompressionImage(string imagePath, long quality)
        {
            using (FileStream fileStream = new FileStream(imagePath, FileMode.Open))
            {
                using (System.Drawing.Image img = System.Drawing.Image.FromStream(fileStream))
                {
                    using (Bitmap bitmap = new Bitmap(img))
                    {
                        ImageCodecInfo CodecInfo = GetEncoder(img.RawFormat);
                        System.Drawing.Imaging.Encoder myEncoder = System.Drawing.Imaging.Encoder.Quality;
                        EncoderParameters myEncoderParameters = new EncoderParameters(1);
                        EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, quality);
                        myEncoderParameters.Param[0] = myEncoderParameter;
                        using (MemoryStream ms = new MemoryStream())
                        {
                            bitmap.Save(ms, CodecInfo, myEncoderParameters);
                            myEncoderParameters?.Dispose();
                            myEncoderParameter?.Dispose();
                            return ms.ToArray();
                        }
                    }
                }
            }
        }

        private static ImageCodecInfo GetEncoder(ImageFormat format)
        {
            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();
            foreach (ImageCodecInfo codec in codecs)
            {
                if (codec.FormatID == format.Guid)
                {
                    return codec;
                }
            }
            return null;
        }
    }
}

下图大小为1.5M，压缩质量设置了50，压缩后的大小为306.6k，压缩前后的质量清晰度还可以接受。