Rotate and Flip an image pixel by pixel - c++

Question

I have the following image, I would like to rotate and flip it so that it fits the full screen resolution.
I'm doing the following conversion, to rotate, but it doesn't work.
Here is the source image.
size_t bpp = Ogre::PixelUtil::getNumElemBytes(source.getFormat());
const unsigned char *srcData = source.getData();
unsigned char *dstData = new unsigned char[width * height * bpp];
size_t srcPitch = source.getRowSpan();
size_t dstPitch = width * bpp;
ImageDescriptor sourceImage(source.getWidth(), source.getHeight(), bpp);
ImageDescriptor rotatedTarget(source.getHeight(), source.getWidth(), bpp); // note width/height swap
unsigned char *rotated = new unsigned char[source.getHeight() * source.getWidth() * bpp];
for (std::size_t row = 0; row < rotatedTarget.mHeight; ++row) {
for (std::size_t col = 0; col < rotatedTarget.mWidth; ++col) {
for (std::size_t chan = 0; chan < rotatedTarget.mChannels; ++chan) {
rotated[rotatedTarget.offset(col, row, chan)] =
srcData[sourceImage.offset(row, col, chan)];
}
}
}
struct ImageDescriptor {
std::size_t mWidth;
std::size_t mHeight;
std::size_t mChannels;
ImageDescriptor(std::size_t width, std::size_t height, std::size_t channels)
{
mWidth = width;
mHeight = height;
mChannels = channels;
}
std::size_t stride() const { return mWidth * mChannels; }
const std::size_t offset(std::size_t row, std::size_t col, std::size_t chan) {
assert(0 <= row && row < mHeight);
assert(0 <= col && col < mWidth);
assert(0 <= chan && chan < mChannels);
// return row*stride() + col*mChannels + chan;
// or, depending on your coordinate system ...
return (mHeight - row - 1)*stride() + col*mChannels + chan;
}
std::size_t size() const { return mHeight * stride(); }
};
Here is the result image.
Answer Result.
Any ideas?

Answer 1

Simple enough, invert the rows, change
rotated[rotatedTarget.offset(col, row, chan)] =
srcData[sourceImage.offset(row, col, chan)];
to
rotated[rotatedTarget.offset(rotatedTarget.mWidth-col-1, row, chan)] =
srcData[sourceImage.offset(row, col, chan)];
Something like that anyway. I'm a bit confused about your code.