c++ - how to imRotate with OpenCV 2.4.3?

Question

how can i implement imrotate(Mat src,Mat dst,double angle) using OpenCV 2.4.3? there is a function warpAffine() but it does to much more and is confusing. and it crops what goes out of bounds.

i want it to make a bigger the canvas to fit everything. and fill empty spots with black.

Answer 1

I solved it like this. thank to your answer.

Mat rotateImage(const Mat source, double angle,int border=20)
{
    Mat bordered_source;
    int top,bottom,left,right;
    top=bottom=left=right=border;
    copyMakeBorder( source, bordered_source, top, bottom, left, right, BORDER_CONSTANT,cv::Scalar() );
    Point2f src_center(bordered_source.cols/2.0F, bordered_source.rows/2.0F);
    Mat rot_mat = getRotationMatrix2D(src_center, angle, 1.0);
    Mat dst;
    warpAffine(bordered_source, dst, rot_mat, bordered_source.size());  
    return dst;
}