Bitmap Invert - CSharp System.Drawing

CSharp examples for System.Drawing:Image Operation

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Description

Bitmap Invert

Demo Code


using System.Drawing.Imaging;
using System.Drawing;
using System;//  w  w  w  . ja  v a2  s  .c om

public class Main{
    public static bool Invert(Bitmap b)
      {
         // GDI+ still lies to us - the return format is BGR, NOT RGB.
         BitmapData bmData = b.LockBits(new Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);

         int stride = bmData.Stride;
         System.IntPtr Scan0 = bmData.Scan0;

         unsafe
         {
            byte * p = (byte *)(void *)Scan0;

            int nOffset = stride - b.Width*3;
            int nWidth = b.Width * 3;
   
            for(int y=0;y<b.Height;++y)
            {
               for(int x=0; x < nWidth; ++x )
               {
                  p[0] = (byte)(255-p[0]);
                  ++p;
               }
               p += nOffset;
            }
         }

         b.UnlockBits(bmData);

         return true;
      }
}

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