Rotate an image

ImageOperator.cpp

void ImageOperator::rotate(const unsigned char* input,
                   const int width,
                   const int height,
                   const int channel,
                   unsigned char*& output){

    unsigned char* tmp = new unsigned char[width*height*channel];
    int step = channel*width;
    for (int row = 0; row < height; ++row) {
        for (int col = 0; col < width*channel; col+=channel) {
            for (int chan = 0; chan < channel; ++chan) {
                tmp[(col/channel)*step+(step-row*channel-1)+chan-(channel-1)] = input[row*step+col+chan];

            }
        }
    }
    output = tmp;

}