[OpenCV] conv2

enum ConvolutionType
{
    /* Return the full convolution, including border */
    CONVOLUTION_FULL,

    /* Return only the part that corresponds to the original image */
    CONVOLUTION_SAME,

    /* Return only the submatrix containing elements that were not influenced by the border */
    CONVOLUTION_VALID
};

void conv2(const cv::Mat &img, cv::Mat& dest, const cv::Mat& kernel, ConvolutionType type)
{
    cv::Mat source = img;
    if (type == CONVOLUTION_FULL)
    {
        source = cv::Mat();
        const int additionalRows = kernel.rows - 1, additionalCols = kernel.cols - 1;
        copyMakeBorder(img, source, (additionalRows + 1) / 2, additionalRows / 2, (additionalCols + 1) / 2, additionalCols / 2, cv::BORDER_CONSTANT, cv::Scalar(0));
    }

    cv::Point anchor(cv::Point(-1, -1));
    int borderMode = cv::BORDER_CONSTANT;
    filter2D(source, dest, img.depth(), kernel.t(), anchor, 0, borderMode);

    if (type == CONVOLUTION_VALID)
    {
        dest = dest.colRange((kernel.cols - 1) / 2, dest.cols - kernel.cols / 2)
            .rowRange((kernel.rows - 1) / 2, dest.rows - kernel.rows / 2);
    }
}

int main(void)
{
    // ....
    cv::Mat imgMat = cv::imread("sample.jpg", CV_LOAD_IMAGE_COLOR);
    cv::Mat gau_mask = cv::getGaussianKernel(7, 1.5, CV_32F);
    conv2(imgMat_bw, imgMat_bw, gau_mask, CONVOLUTION_SAME);

    return 0;
}