where
The where
command retrieves the rectangle specifying the source or destination area. This
rectangle was specified using the put command. Digital-video, and video-overlay
devices recognize this command.
wsprintf(lpstrCommand, "where %s %s %s",
lpszDeviceID, lpszRequestRect,
lpszFlags);
Parameters
lpszDeviceID
Identifier of
an MCI device. This identifier or alias is assigned when the device is opened.
lpszRequestRect
Flag that
identifies the rectangle whose dimensions are retrieved. The following table
lists device types that recognize the where command and the flags used
by each type:
|
digitalvideo |
destination |
source max |
|
overlay |
destination |
source |
The following
table lists the flags that can be specified in the lpszRequestRect parameter
and their meanings:
|
destination |
Retrieves
the destination offset and extent. For video-overlay devices, the destination
rectangle defines the area of the display window client area that displays
the image data from the frame buffer. |
|
destination
max |
Retrieves
the current size of the client rectangle. |
|
frame |
Retrieves
the offset and extent of the frame buffer rectangle. The frame buffer
rectangle defines the area of the frame buffer that receives incoming video
data. Images from the video rectangle are scaled into this region. |
|
frame max |
Returns the
maximum size of the frame buffer. |
|
source |
Retrieves
the source offset and extent. For video-overlay devices, the source rectangle
defines the region of the frame buffer that is displayed in the destination
window. The device uses this rectangle to crop the image before it is
stretched to fit the destination rectangle on the display. |
|
source max |
Retrieves
the maximum size of the frame buffer. |
|
video |
Retrieves
the offset and extent of the video rectangle. The video rectangle defines the
region of the incoming video data that is transferred to the frame buffer. |
|
video max |
Returns the
maximum size of the input. |
|
window |
Retrieves
the current size and position of the display-window frame. |
|
window max |
Retrieves
the size of the entire display. |
lpszFlags
Can be
wait , notify , or both. For digital-video devices, test can also be
specified. For more information about these flags, see The Wait, Notify, and
Test Flags.
Return Values
Returns a
rectangle in the lpstrReturnString parameter of the mciSendString function. The rectangle
describes the area specified in the lpszRequestRect parameter of this
command. The rectangle is specified as X1 Y1 X2 Y2. The coordinates X1
Y1 specify the upper left corner of the rectangle, and the coordinates X2
Y2 specify the width and height.
Remarks
The following
command returns the display rectangle of the movie device:
where movie destination
See Also