c#图片压缩到固定大小怎么实现

你可以使用C#中的System.Drawing命名空间来实现图片的压缩。下面是一个简单的示例代码，演示如何将图片压缩到指定的大小：

using System; using System.Drawing; using System.Drawing.Imaging; using System.IO;  public class ImageCompressor {     public void CompressImage(string sourcePath, string outputPath, int maxWidth, int maxHeight)     {         using (Image sourceImage = Image.FromFile(sourcePath))         {             double aspectRatio = (double)sourceImage.Width / sourceImage.Height;             int newWidth = maxWidth;             int newHeight = (int)(maxWidth / aspectRatio);              if (newHeight > maxHeight)             {                 newHeight = maxHeight;                 newWidth = (int)(maxHeight * aspectRatio);             }              using (Bitmap compressedImage = new Bitmap(newWidth, newHeight))             {                 using (Graphics graphics = Graphics.FromImage(compressedImage))                 {                     graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;                     graphics.DrawImage(sourceImage, 0, 0, newWidth, newHeight);                 }                  compressedImage.Save(outputPath, ImageFormat.Jpeg);             }         }     } }  class Program {     static void Main()     {         ImageCompressor compressor = new ImageCompressor();         compressor.CompressImage("source.jpg", "compressed.jpg", 800, 600);     } } 

在上面的示例代码中，CompressImage方法接受源图片的路径、输出路径以及目标宽度和高度作为参数。算法会计算出适合目标宽度和高度的图片尺寸，并将源图片按照这个尺寸进行压缩保存为JPEG格式。您可以根据需要调整压缩质量和输出格式。