The following code illustrates how to return the video destination rectangle with MCI_WHERE.
MCI_DGV_RECT_PARMS mciRectParms;
USHORT usUserParm = 0;
ULONG ulReturn;
CHAR szText[255];
CHAR szValue[20];
LONG lX1, lX2, lY1, lY2;
/* A sample to query the current destination */
/* video sub-rectangle within the video window */
memset (&mciRectParms, 0x00, sizeof (MCI_DGV_RECT_PARMS));
mciRectParms.hwndCallback = hwndNotify;
ulReturn = mciSendCommand(usDeviceID, MCI_WHERE,
MCI_WAIT | MCI_DGV_WHERE_DESTINATION,
(PVOID)&mciRectParms,
usUserParm);
lX1 = mciRectParms.rc.xLeft;
lY1 = mciRectParms.rc.yBottom;
lX2 = mciRectParms.rc.xRight;
lY2 = mciRectParms.rc.yTop;