Bug in cvCopyMakeBorder(...BORDER_REFLECT_101) (Feature #748)

When padding an image (cv::Mat_<float>) using a call to cvCopyMakeBorder with REFLECT_101 as border type, the added top and bottom rows of the image are not set correctly. Actually what happens is that source and destination pointers are switched so that when copying the data the uninitialized border overwrites the inner part of the image.

Sample code:
typedef int ValueType;
cv::Mat_<ValueType> image = cv::Mat_<ValueType>::zeros(3, 3);
int padding = 2;
cv::Mat_<ValueType> padded =
cv::Mat_<ValueType>::ones(image.rows + 2*padding, image.cols + 2*padding);
cv::copyMakeBorder(image, padded,
padding, padding, padding, padding,
cv::BORDER_REFLECT_101);

Resulting images:

image:
[
0 0 0
0 0 0
0 0 0
]
padded:
[
1 1 1 1 1 1 1
1 1 1 1 1 1 1
1 1 1 1 1 1 1
1 1 1 1 1 1 1
0 0 0 0 0 0 0
1 1 1 1 1 1 1
1 1 1 1 1 1 1
]

But one expects:
padded:
[
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
]

This affects matrices of all types (uchars, ints, floats...).

Tested with both OpenCV 2.1 and 2.2 and there is the bug in both.

A patch is attached.