Deskewing Image OpenCV - c++

Question

I have followed this article on how to calculate and deskew an image for better Tesseract OCR results: http://felix.abecassis.me/2011/10/opencv-rotation-deskewing/
The correct angle is calculated, but the text is never actually rotated.
These are the methods I am using:
+(UIImage *) prepareImage: (UIImage *)image{
return deskew(image, computeSkew(image));
}
// Organization -> Deskewing
double computeSkew(UIImage *image)
{
Mat src;
UIImageToMat(image, src);
cv::Size size = src.size();
bitwise_not(src, src);
vector<Vec4i> lines;
HoughLinesP(src, lines, 1, CV_PI/180, 100, size.width / 2.f, 20);
Mat disp_lines(size, CV_8UC1, Scalar(0, 0, 0));
double angle = 0.;
unsigned nb_lines = lines.size();
for (unsigned i = 0; i < nb_lines; ++i)
{
line(disp_lines, cv::Point(lines[i][0], lines[i][1]),
cv::Point(lines[i][2], lines[i][3]), Scalar(255, 0 ,0));
angle += atan2((double)lines[i][3] - lines[i][1],
(double)lines[i][2] - lines[i][0]);
}
angle /= nb_lines; // mean angle, in radians.
cout << angle << endl;
return angle;
}
UIImage* deskew(UIImage *image, double angle)
{
Mat img;
UIImageToMat(image, img);
bitwise_not(img, img);
vector<cv::Point> points;
Mat_<uchar>::iterator it = img.begin<uchar>();
Mat_<uchar>::iterator end = img.end<uchar>();
for (; it != end; ++it)
if (*it)
points.push_back(it.pos());
RotatedRect box = minAreaRect(Mat(points));
Mat rot_mat = getRotationMatrix2D(box.center, angle, 1);
Mat rotated;
warpAffine(img, rotated, rot_mat, img.size(), INTER_CUBIC);
return MatToUIImage(rotated);
}
UIImageToMat and MatToUIImage are reliable methods that convert back and forth. I have also tried to return the angle in both radians and degrees. Both times the image returned from the prepareImage function is still tilted at the same angle as the original image.