DongHeZheng

void imageScaleAndRotate(const cv::Mat &src, cv::Mat &out, double scale, double roll) {
    // scaling
		cv::Mat imSmall;
		cv::resize(src, imSmall, cv::Size(), scale, scale);
    
    // prepare for rotating
		int width = imSmall.cols, height = imSmall.rows;
		int diagonal = int(sqrt(height * height + width * width));

		int offsetX = (diagonal - width) / 2, offsetY = (diagonal - height) / 2;