CCD영상도 잘 나오고 있고 OverLay로 영상 위에 원하는 도형까지 잘 그려는 지는데

MbufClear(m_MilOverlayImage, TransparentColor);

를 하여도 그렸던 도형이 색만 검정색으로 바뀌고 영상위에 그대로 남아있습니다.

어떤 부분을 확인해 봐야 될까요?

Mil 초기화 부분
//---------------------------------------------------------------------------
MappAlloc(M_DEFAULT, &m_MilApplication);

  MsysAlloc(M_DEF_SYSTEM_TYPE, M_DEF_SYSTEM_NUM, M_SETUP, &m_MilSystem);

  MdispAlloc(m_MilSystem, M_DEF_DISPLAY_NUM, M_DEF_DISPLAY_FORMAT, M_WINDOWED, &m_MilDisplay);

  if (MsysInquire(m_MilSystem, M_DIGITIZER_NUM, M_NULL) > 0){
   MdigAlloc(m_MilSystem, M_DEV0, "NTSC.dcf", M_DEFAULT, &m_MilDigitizer);

   MdigInquire(m_MilDigitizer, M_SIZE_X,    &BufSizeX);
   MdigInquire(m_MilDigitizer, M_SIZE_Y,    &BufSizeY);
   MdigInquire(m_MilDigitizer, M_SIZE_BAND, &BufSizeBand);
  }
  else  {
   m_MilDigitizer = M_NULL;
   BufSizeX     = 640; 
   BufSizeY     = 480;
   BufSizeBand  = 1;
  }

  MbufAllocColor(m_MilSystem, BufSizeBand, 640, 480, M_DEF_IMAGE_TYPE,
   (M_IMAGE+M_DISP+M_GRAB+M_PROC), &m_MilImage);

  MbufClear(m_MilImage,0);
//---------------------------------------------------------------------------

Overlay 셋팅 부분
//---------------------------------------------------------------------------
   MdispControl(m_MilDisplay, M_WINDOW_OVR_SHOW, M_DISABLE);

   MdispControl(m_MilDisplay, M_WINDOW_OVR_WRITE, M_ENABLE);

   MdispInquire(m_MilDisplay, M_WINDOW_OVR_BUF_ID, &m_MilOverlayImage);

   MdispInquire(m_MilDisplay, M_KEY_COLOR, &TransparentColor);

   MbufClear(m_MilOverlayImage, TransparentColor);

   MdispControl(m_MilDisplay, M_WINDOW_OVR_SHOW, M_ENABLE);

   MgraControl(M_DEFAULT, M_BACKGROUND_MODE, M_TRANSPARENT);
//---------------------------------------------------------------------------

영상 처리
//---------------------------------------------------------------------------
if (m_MilDigitizer){
  MdigGrabContinuous(m_MilDigitizer, m_MilImage);
}
//---------------------------------------------------------------------------

직선 그리는 부분
//---------------------------------------------------------------------------
   MgraColor(M_DEFAULT, M_RGB888(255, 0, 0));
   MgraLine(M_DEFAULT, m_MilOverlayImage, vGeomPtOld.x, vGeomPtOld.y, vGeomPt.x, vGeomPt.y );
//---------------------------------------------------------------------------

지워주는 부분
//---------------------------------------------------------------------------
    MbufClear(m_MilOverlayImage, TransparentColor);
//---------------------------------------------------------------------------