Function cvSetImageROI

deps/opencv/modules/core/src/array.cpp:2996–3028

CV_IMPL void
cvSetImageROI( IplImage* image, CvRect rect )
{
    if( !image )
        CV_Error( CV_HeaderIsNull, "" );

    // allow zero ROI width or height
    CV_Assert( rect.width >= 0 && rect.height >= 0 &&
               rect.x < image->width && rect.y < image->height &&
               rect.x + rect.width >= (int)(rect.width > 0) &&
               rect.y + rect.height >= (int)(rect.height > 0) );

    rect.width += rect.x;
    rect.height += rect.y;

    rect.x = std::max(rect.x, 0);
    rect.y = std::max(rect.y, 0);
    rect.width = std::min(rect.width, image->width);
    rect.height = std::min(rect.height, image->height);

    rect.width -= rect.x;
    rect.height -= rect.y;

    if( image->roi )
    {
        image->roi->xOffset = rect.x;
        image->roi->yOffset = rect.y;
        image->roi->width = rect.width;
        image->roi->height = rect.height;
    }
    else
        image->roi = icvCreateROI( 0, rect.x, rect.y, rect.width, rect.height );
}


CV_IMPL void