Question

如上所述，我想使用C＃和lockBits方法模糊图像的一部分。我已经测试过设置/获取像素，但是，这很慢。这是代码，不知道我在做什么错。

    static unsafe void FastBlur(Bitmap image, int i, int j, int w, int h)
    {
        BitmapData imgData = image.LockBits(new Rectangle(i,j,w,h), ImageLockMode.ReadWrite, image.PixelFormat);
        int bytesPerPixel = 3;
        byte* scan0 = (byte*)imgData.Scan0.ToPointer();
        int stride = imgData.Stride;
        for (int y = 0; y < imgData.Height; y++)
        {
            byte* row = scan0 + (y * stride);

            for (int x = 0; x < imgData.Width; x++)
            {
                // Watch out for actual order (BGR)!
                int bIndex = x * bytesPerPixel;
                int gIndex = bIndex + 1;
                int rIndex = bIndex + 2;                    

                byte pixelR = (byte)((row[rIndex + 1] + row[rIndex - 1] + row[rIndex + w] + row[rIndex - w]) / 4);
                byte pixelG = (byte)((row[gIndex + 1] + row[gIndex - 1] + row[gIndex + w] + row[gIndex - w]) / 4);
                byte pixelB = (byte)((row[bIndex + 1] + row[bIndex - 1] + row[bIndex + w] + row[bIndex - w]) / 4);

                byte result = (byte)(pixelB + pixelG + pixelR);

                row[x + y * image.Width] = result;
            }
        }
        image.UnlockBits(imgData);
    }

Answer 1

byte* scan0 = (byte*)imgData.Scan0.ToPointer();
    int stride = imgData.Stride;
    for (int y = 0; y < imgData.Height; y++)
    {
        byte* row = scan0;

        for (int x = 0; x < imgData.Width; x++)
        {
            // Watch out for actual order (BGR)!
            int bIndex = x * bytesPerPixel;
            int gIndex = bIndex + 1;
            int rIndex = bIndex + 2;                    

            byte pixelR = (byte)((row[rIndex + 1] + row[rIndex - 1] + row[rIndex + w] + row[rIndex - w]) / 4);
            byte pixelG = (byte)((row[gIndex + 1] + row[gIndex - 1] + row[gIndex + w] + row[gIndex - w]) / 4);
            byte pixelB = (byte)((row[bIndex + 1] + row[bIndex - 1] + row[bIndex + w] + row[bIndex - w]) / 4);

            byte result = (byte)(pixelB + pixelG + pixelR);

           // row is not a single value its a pixel with 3 byte values so :
            *(row++) = pixelB;
            *(row++) = pixelG;
            *(row++) = pixelR; // or set all to result value but you should move the pointer
        }
         scan0+=stride; // move to next row
    }
    image.UnlockBits(imgData);

C＃，使用lockBits模糊图像的一部分

1 个答案: