troubleshooting Question

Foreach, Or Not Foreach.

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derekthornton asked on
32 Comments1 Solution473 ViewsLast Modified:
I've got this method ..or rather series of methods that cycles through every pixel in an image using unmanaged code. One of which is displayed below ( this particular one, in conjunction with some other methods, checks a page to see if it is blank or has anything on it ).
I'd like to come up with a way to just have a template-like method stored in a .dll file, and then cycle through all the pixels using a Foreach loop on an image. For instance..

foreach(UnmanagedPixel p in iImage)

...Is this even possible? I've got no idea where to even begin to attempt something like this. Here's the sample method.

            public static Boolean ValidatePage(Image imgImage)
                  // Store our blank pixel count
                  double dblBlankPixels = 0.0;
                  // Store our pixel count
                  double dblTotalPixels = 0.0;
                  // Work with a Bitmap copy
                  Bitmap bmImage = (Bitmap)imgImage.Clone();

                  // Lock the bits
                  BitmapData bmData = bmImage.LockBits
                        (new Rectangle(Point.Empty,bmImage.Size),

                  // Retrieve the Bitmap Stride Width
                  Int32 Stride = bmData.Stride;
                  // Create Unmanaged memory for this code
                  IntPtr Scan0 = bmData.Scan0;

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

                        Int32 nOffset = Stride  - bmImage.Width * 3;
                        Int32 nWidth  = bmImage.Width * 3;

                        for(int y = 0; y < bmImage.Height; ++y)
                              for(int x=0; x < nWidth; ++x )
                                    if(p[0] >= (byte)(225))
                              p += nOffset;
                  // Unlock the bitmap
                  // Destroy it

                  return ComparePixelData(dblBlankPixels,dblTotalPixels);

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