Function icvReadImage

deps/opencv/modules/core/src/persistence.cpp:3946–4012

static void*
icvReadImage( CvFileStorage* fs, CvFileNode* node )
{
    void* ptr = 0;
    IplImage* image;
    const char* dt;
    CvFileNode* data;
    CvFileNode* roi_node;
    CvSeqReader reader;
    CvRect roi;
    int y, width, height, elem_type, coi, depth;
    const char* origin, *data_order;

    width = cvReadIntByName( fs, node, "width", 0 );
    height = cvReadIntByName( fs, node, "height", 0 );
    dt = cvReadStringByName( fs, node, "dt", 0 );
    origin = cvReadStringByName( fs, node, "origin", 0 );

    if( width == 0 || height == 0 || dt == 0 || origin == 0 )
        CV_Error( CV_StsError, "Some of essential image attributes are absent" );

    elem_type = icvDecodeSimpleFormat( dt );
    data_order = cvReadStringByName( fs, node, "layout", "interleaved" );
    if( strcmp( data_order, "interleaved" ) != 0 )
        CV_Error( CV_StsError, "Only interleaved images can be read" );

    data = cvGetFileNodeByName( fs, node, "data" );
    if( !data )
        CV_Error( CV_StsError, "The image data is not found in file storage" );

    if( icvFileNodeSeqLen( data ) != width*height*CV_MAT_CN(elem_type) )
        CV_Error( CV_StsUnmatchedSizes,
        "The matrix size does not match to the number of stored elements" );

    depth = cvIplDepth(elem_type);
    image = cvCreateImage( cvSize(width,height), depth, CV_MAT_CN(elem_type) );

    roi_node = cvGetFileNodeByName( fs, node, "roi" );
    if( roi_node )
    {
        roi.x = cvReadIntByName( fs, roi_node, "x", 0 );
        roi.y = cvReadIntByName( fs, roi_node, "y", 0 );
        roi.width = cvReadIntByName( fs, roi_node, "width", 0 );
        roi.height = cvReadIntByName( fs, roi_node, "height", 0 );
        coi = cvReadIntByName( fs, roi_node, "coi", 0 );

        cvSetImageROI( image, roi );
        cvSetImageCOI( image, coi );
    }

    if( width*CV_ELEM_SIZE(elem_type) == image->widthStep )
    {
        width *= height;
        height = 1;
    }

    width *= CV_MAT_CN(elem_type);
    cvStartReadRawData( fs, data, &reader );