Function cvGetMat

deps/opencv/modules/core/src/array.cpp:2373–2488

convert array (CvMat or IplImage) to CvMat

// convert array (CvMat or IplImage) to CvMat
CV_IMPL CvMat*
cvGetMat( const CvArr* array, CvMat* mat,
          int* pCOI, int allowND )
{
    CvMat* result = 0;
    CvMat* src = (CvMat*)array;
    int coi = 0;

    if( !mat || !src )
        CV_Error( CV_StsNullPtr, "NULL array pointer is passed" );

    if( CV_IS_MAT_HDR(src))
    {
        if( !src->data.ptr )
            CV_Error( CV_StsNullPtr, "The matrix has NULL data pointer" );

        result = (CvMat*)src;
    }
    else if( CV_IS_IMAGE_HDR(src) )
    {
        const IplImage* img = (const IplImage*)src;
        int depth, order;

        if( img->imageData == 0 )
            CV_Error( CV_StsNullPtr, "The image has NULL data pointer" );

        depth = IPL2CV_DEPTH( img->depth );
        if( depth < 0 )
            CV_Error( CV_BadDepth, "" );

        order = img->dataOrder & (img->nChannels > 1 ? -1 : 0);

        if( img->roi )
        {
            if( order == IPL_DATA_ORDER_PLANE )
            {
                int type = depth;

                if( img->roi->coi == 0 )
                    CV_Error( CV_StsBadFlag,
                    "Images with planar data layout should be used with COI selected" );

                cvInitMatHeader( mat, img->roi->height,
                                img->roi->width, type,
                                img->imageData + (img->roi->coi-1)*img->imageSize +
                                img->roi->yOffset*img->widthStep +
                                img->roi->xOffset*CV_ELEM_SIZE(type),
                                img->widthStep );
            }
            else /* pixel order */
            {
                int type = CV_MAKETYPE( depth, img->nChannels );
                coi = img->roi->coi;

                if( img->nChannels > CV_CN_MAX )
                    CV_Error( CV_BadNumChannels,
                        "The image is interleaved and has over CV_CN_MAX channels" );