Howto: Extract Overlay Data

Here's an example that shows how it works in principle:

#include "dcmtk/config/osconfig.h" 
#include "dcmtk/dcmimgle/dcmimage.h" 
 
int main(int argc, char *argv[]) 
{ 
    DicomImageClass::setDebugLevel(0xff); 
    DicomImage img("overlay_image.dcm"); 
    if (img.getStatus() == EIS_Normal)    
    { 
#ifdef EXPORT_FULL_OVERLAY 
        unsigned int width, height; 
        /* create bitmap (1 bit) for first overlay plane */
        Uint8 *data = (Uint8 *)img.getFullOverlayData(0, width, height, 0, 1, 0, 1); 
        const size_t size = (size_t)((width * height + 7) / 8); 
#else 
        unsigned int left, top, width, height; 
        EM_Overlay mode; 
        /* create bitmap (8 bit) for first overlay plane, cropped to image size */
        Uint8 *data = (Uint8 *)img.getOverlayData(0, left, top, width, height, mode); 
        const size_t size = (size_t)(width * height); 
#endif 
        if (data != NULL) 
        { 
            COUT << "overlay: " << width << " / " << height << OFendl; 
            /* write overlay data (bitmap) to a file */
            FILE *file = fopen("overlay.raw", "wb"); 
            if (file != NULL) 
            { 
                fwrite(data, size, 1, file); 
                fclose(file); 
            } 
        } else 
            CERR << "no such overlay plane" << OFendl; 
    } 
    return 0; 
}