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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
destination max
frame
frame max
source
| source max
video
video max
window
window max
| overlay
| destination
frame
| source
video
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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.
| | 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.
| | 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.
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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
mciSendString, put
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