Method copyMakeBorder

deps/opencv/modules/imgproc/src/utils.cpp:204–256

}

void cv::copyMakeBorder( InputArray _src, OutputArray _dst, int top, int bottom,
                         int left, int right, int borderType, const Scalar& value )
{
    Mat src = _src.getMat();
    CV_Assert( top >= 0 && bottom >= 0 && left >= 0 && right >= 0 );

    if( src.isSubmatrix() && (borderType & BORDER_ISOLATED) == 0 )
    {
        Size wholeSize;
        Point ofs;
        src.locateROI(wholeSize, ofs);
        int dtop = std::min(ofs.y, top);
        int dbottom = std::min(wholeSize.height - src.rows - ofs.y, bottom);
        int dleft = std::min(ofs.x, left);
        int dright = std::min(wholeSize.width - src.cols - ofs.x, right);
        src.adjustROI(dtop, dbottom, dleft, dright);
        top -= dtop;
        left -= dleft;
        bottom -= dbottom;
        right -= dright;
    }

    _dst.create( src.rows + top + bottom, src.cols + left + right, src.type() );
    Mat dst = _dst.getMat();

    if(top == 0 && left == 0 && bottom == 0 && right == 0)
    {
        if(src.data != dst.data || src.step != dst.step)
            src.copyTo(dst);
        return;
    }

    borderType &= ~BORDER_ISOLATED;

    if( borderType != BORDER_CONSTANT )
        copyMakeBorder_8u( src.data, src.step, src.size(),
                           dst.data, dst.step, dst.size(),
                           top, left, (int)src.elemSize(), borderType );
    else
    {
        int cn = src.channels(), cn1 = cn;
        AutoBuffer<double> buf(cn);
        if( cn > 4 )
        {
            CV_Assert( value[0] == value[1] && value[0] == value[2] && value[0] == value[3] );
            cn1 = 1;
        }
        scalarToRawData(value, buf, CV_MAKETYPE(src.depth(), cn1), cn);
        copyMakeConstBorder_8u( src.data, src.step, src.size(),
                                dst.data, dst.step, dst.size(),
                                top, left, (int)src.elemSize(), (uchar*)(double*)buf );
    }
}


double cv::PSNR(InputArray _src1, InputArray _src2)