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Today Xiaobian to share with you how to achieve lossless compression of C#related knowledge points, detailed content, clear logic, I believe most people still know too much about this knowledge, so share this article for everyone to refer to, I hope you read this article after some gains, let's learn about it together.

Generally, in web applications, images submitted by clients must be compressed. Especially for large pictures, if not compressed, the page will become very large, and the opening speed will be slow, affecting the user experience, so the picture will generally be compressed.

Code implementation:

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Drawing.Imaging;using System.IO;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows.Forms;namespace ImageCompress{ public partial class Form1 : Form { public Form1() { InitializeComponent(); } /// ///Lossless compression of images /// ///Original image address (including image name) ///Save image address after compression (including image name) ///Compression quality (the smaller the number, the higher the compression ratio) 1-100 ///Maximum size of compressed image ///is this the first call /// public static bool CompressImage(string sFile, string dFile, int flag = 90, int size = 300, bool sfsc = true) { //If this is the first call and the original image size is smaller than the size to be compressed, copy the file directly and return true FileInfo firstFileInfo = new FileInfo(sFile); if (sfsc == true && firstFileInfo.Length

< size * 1024) { firstFileInfo.CopyTo(dFile); return true; } Image iSource = Image.FromFile(sFile); ImageFormat tFormat = iSource.RawFormat; int dHeight = iSource.Height / 2; int dWidth = iSource.Width / 2; 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 = System.Drawing.Drawing2D.CompositingQuality.HighQuality; g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; g.InterpolationMode = System.Drawing.Drawing2D.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(); //The following code sets the compression quality when saving images EncoderParameters ep = new EncoderParameters(); long[] qy = new long[1]; qy[0] = flag;//Set compression ratio 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 FileInfo fi = new FileInfo(dFile); if (fi.Length >

1024 * size) { flag = flag - 10; CompressImage(sFile, dFile, flag, size, false); } } else { ob.Save(dFile, tFormat); } return true; } catch { return false; } finally { iSource.Dispose(); ob.Dispose(); } } private void button1_Click(object sender, EventArgs e) { string sfile = @"C:\Users\Mingliang_wang\Pictures\Screenshots\s_test.jpg"; string dfile = @"C:\Users\Mingliang_wang\Pictures\Screenshots\d_test.jpg"; CompressImage(sfile,dfile); } }} The above is all the content of this article "How to achieve lossless compression of images in C#". Thank you for reading! I believe everyone has a great harvest after reading this article. Xiaobian will update different knowledge for everyone every day. If you want to learn more knowledge, please pay attention to the industry information channel.

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