GetDIBits and loop through pixels using X, Y

Question

I\'m grabbing a portion of the screen and scanning through the pixels for a certain color range.

I looked at MSDN\'s Capturing an Image example and know how to use t

Answer 1

In the link you post you create a 32-bit bitmap so I'll assume you are reading from a 32-bit bitmap (This assumption may be incorrect).

Therefore changing your loop to the following should work:

char* pCurrPixel = (char*)lpPixels;
for ( y = 0; y < Image.Height; y++ )
{
    for ( x = 0; x < Image.Width; x++ )
    {
        red = pCurrPixel[0];
        green = pCurrPixel[1];
        blue = pCurrPixel[2];

        pCurrPixel += 4;
    }
}

Things to bear in mind:

1.Arrays are 0 based in C/C++
2. You were stepping 3 pixels horizontally and vertically each time. Which meant you aren't visiting every pixel.
3. A bitmap is usually organised such that there are "height" spans of "width" pixels. Therefore you should step through each pixel in a span and then move to the next span.
4. As already pointed out make sure you aare reading pixels correctly. in 16-bit mode its more complex