MCI_WHERE

This message returns the coordinates of the source and destination rectangles, as well as the current location of the video window.

Syntax

param1
ULONG ulParam1; /* Message flags. */

param2
PMCI_VID_RECT_PARMS pParam2; /* Pointer to rectangle structure. */

Parameters

ulParam1 (ULONG) - input

This parameter can contain any of the following flags:

* MCI_NOTIFY — Posts a notification message when the action completes.

* MCI_WAIT — Does not return control until the action completes.

Digital Video Extensions

* MCI_DGV_WHERE_DESTINATION — Returns the destination display rectangle in the `rc` field.

* MCI_DGV_WHERE_SOURCE — Returns the video source rectangle in the `rc` field.

* MCI_DGV_WHERE_ADJUSTED — Used with `RECORD` flags. Returns the actual coordinates that will be used by capture hardware based on MCI_PUT settings.

* MCI_DGV_WHERE_WINDOW — Returns the current location of the video window relative to its parent.

* MCI_DGV_MONITOR — Returns the size and position for the monitor window.

* MCI_DGV_RECORD — Returns the source and destination rectangles for video capture.

Video Overlay Extensions

* MCI_OVLY_WHERE_DESTINATION — Returns the destination display rectangle.

* MCI_OVLY_WHERE_SOURCE — Returns the video overlay source rectangle.

* MCI_OVLY_WHERE_WINDOW — Returns the video window location relative to its parent.

pParam2 (PMCI_VID_RECT_PARMS) - input/output

A pointer to an MCI_VID_RECT_PARMS structure. Specific devices may require:

* PMCI_DGV_RECT_PARMS — For digital video devices.

* PMCI_OVLY_RECT_PARMS — For video overlay devices.

Return Value

rc (ULONG)

* MCIERR_SUCCESS — Command completed successfully.

* MCIERR_OUT_OF_MEMORY — System out of memory.

* MCIERR_INVALID_DEVICE_ID — Invalid device ID.

* MCIERR_MISSING_PARAMETER — A required parameter is missing.

* MCIERR_DRIVER — Internal driver error.

* MCIERR_INVALID_FLAG — Invalid flag specified.

* MCIERR_FLAGS_NOT_COMPATIBLE — Specified flags cannot be used together.

* MCIERR_INSTANCE_INACTIVE — Device instance is inactive.

Remarks

The flags and parameters available depend on the specific device being queried.

Note: The resulting coordinates are returned directly into the rc (RECTL) field of the structure pointed to by pParam2.

Related Messages

• MCI_WINDOW
• MCI_PUT

Example Code

The following code demonstrates how to query the current destination video sub-rectangle within the video window.

    MCI_DGV_RECT_PARMS  mciRectParms;
    USHORT  usUserParm = 0;
    ULONG   ulReturn;
    LONG    lX1, lX2, lY1, lY2;

    /* Initialize structure */
    memset (&mciRectParms, 0x00, sizeof (MCI_DGV_RECT_PARMS));
    mciRectParms.hwndCallback = hwndNotify;

    /* Query the current destination rectangle */
    ulReturn = mciSendCommand(usDeviceID, MCI_WHERE,
                   MCI_WAIT | MCI_DGV_WHERE_DESTINATION,
                   (PVOID)&mciRectParms,
                   usUserParm);

    /* Extract coordinates from the returned RECTL structure */
    lX1 = mciRectParms.rc.xLeft;
    lY1 = mciRectParms.rc.yBottom;
    lX2 = mciRectParms.rc.xRight;
    lY2 = mciRectParms.rc.yTop;