using System.Drawing;using System.Drawing.Imaging;using System.Web.Mvc;namespace MVC2017_Sample.Controllers{ public class DefaultController : Controller {  public ActionResult Index()  {   //原圖   Image img = Image.FromFile("c://1.jpg");   Bitmap map = new Bitmap(img);   //馬賽克處理后的圖片   Image img2 = AdjustTobMosaic(map, 20);   img2.Save("c://1_bak.jpg", ImageFormat.Jpeg);   return View();  }  /// <summary>  /// 馬賽克處理  /// </summary>  /// <param name="bitmap"></param>  /// <param name="effectWidth"> 影響范圍 每一個格子數 </param>  /// <returns></returns>  public Bitmap AdjustTobMosaic(System.Drawing.Bitmap bitmap, int effectWidth)  {   // 差異最多的就是以照一定范圍取樣 玩之后直接去下一個范圍   for (int heightOfffset = 0; heightOfffset < bitmap.Height; heightOfffset += effectWidth)   {    for (int widthOffset = 0; widthOffset < bitmap.Width; widthOffset += effectWidth)    {     int avgR = 0, avgG = 0, avgB = 0;     int blurPixelCount = 0;     for (int x = widthOffset; (x < widthOffset + effectWidth && x < bitmap.Width); x++)     {      for (int y = heightOfffset; (y < heightOfffset + effectWidth && y < bitmap.Height); y++)      {       System.Drawing.Color pixel = bitmap.GetPixel(x, y);       avgR += pixel.R;       avgG += pixel.G;       avgB += pixel.B;       blurPixelCount++;      }     }     // 計算范圍平均     avgR = avgR / blurPixelCount;     avgG = avgG / blurPixelCount;     avgB = avgB / blurPixelCount;     // 所有范圍內都設定此值     for (int x = widthOffset; (x < widthOffset + effectWidth && x < bitmap.Width); x++)     {      for (int y = heightOfffset; (y < heightOfffset + effectWidth && y < bitmap.Height); y++)      {       System.Drawing.Color newColor = System.Drawing.Color.FromArgb(avgR, avgG, avgB);       bitmap.SetPixel(x, y, newColor);      }     }    }   }   return bitmap;  } }}