Dealing with padding in a BMP file in C

Question

I am trying to edit a BMP file in C. My code works for BMP files with no padding but I am having trouble dealing with padding.

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Answer 1

The "padding bytes" are the bytes following the pixels of a scanline. You are not so interested in the padding as in the scanline size and pixel size:

iScanlineSize  = ((width * bitsperpixel) + 31) / 32 * 4;
iBytesperPixel = bitsperpixel / 8;

Now you can loop over scanlines and adress pixels and pixel parts (colors) as follows:

for (int a = 0; a < height; a++) {
    for (int b = 0; b < width; b++) {
        for (int c = 0; c < iBytesperPixel; c++) {
            pixelPart= bmpArray[a*iScanlineSize + b*iBytesperPixel + c];
        }
    ]
}