FRDocument 物件的 AddImageFile 方法

// 當載入影像耗時過久時啟用逾時機制
frDocumentCallback.SetShouldTrackTime( true );
frDocumentCallback.FlushTimer();
// 呼叫 AddImageFile 方法以開啟影像檔案
CheckResult( frDocument->AddImageFile( imageFilePath, 0, pageIndices ) );
// 針對後續處理關閉逾時機制
frDocumentCallback.SetShouldTrackTime( false );
...
// 使用 IFRDocumentEvents 回呼介面來回報事件
class CFRDocumentCallback: public IFRDocumentEvents {
public:
    CFRDocumentCallback() : startTime( 0 ) {}
 
    // 實作 IUnknown 方法
    ULONG STDMETHODCALLTYPE AddRef() { return 1; }
    ULONG STDMETHODCALLTYPE Release() { return 1; }
    HRESULT STDMETHODCALLTYPE QueryInterface( REFIID riid, void** ppObject );
    HRESULT STDMETHODCALLTYPE OnProgress( IFRDocument* document, int percentage, VARIANT_BOOL* ShouldContinue );
    HRESULT STDMETHODCALLTYPE OnWarning( IFRDocument* frPage, int pageNumber, BSTR recognizerTip, 
        VARIANT_BOOL* ShouldContinue );
    HRESULT STDMETHODCALLTYPE OnPageProcessed( IFRDocument* document, int pageNumber, PageProcessingStageEnum stage );
    void FlushTimer();
    void SetShouldTrackTime( bool _shouldTrackTime );
private:
    time_t startTime;
    bool shouldTrackTime = true;
};
// 呼叫 FlushTimer 方法以重設 startTime
void CFRDocumentCallback::FlushTimer() {
    time( &startTime );
}
// 此回呼也可能用於其他方法，因此如果您不想再重設逾時，請將 shouldTrackTime 設為 FALSE 
void CFRDocumentCallback::SetShouldTrackTime( bool _shouldTrackTime ) {
    shouldTrackTime = _shouldTrackTime;
}
 
// 如果目前時間與「startTime」之間的差值超過某個門檻，程序就會中止。AddImageFile 方法會將 0 
傳遞給 OnProgress 方法，而不是 percentage
HRESULT STDMETHODCALLTYPE CFRDocumentCallback::OnProgress( IFRDocument* frDocument, int percentage, 
    VARIANT_BOOL* shouldTerminate )
{
    if( shouldTrackTime ) {
        time_t currentTime;
        time( ¤tTime );
        double seconds = difftime( currentTime, startTime );
        printf( "%f\n", seconds );
        *shouldTerminate = ( seconds > 100 ? VARIANT_TRUE : VARIANT_FALSE );
    }
    return S_OK;
}