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.
where device request_rect flags
device
Identifier of an MCI device. This identifier or alias is assigned when the device is opened.
request_rect
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 request_rect 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. |
flags
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.
Returns a rectangle. The rectangle describes the area specified in the request_rect 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.
The following command returns the display rectangle of the “movie” device:
where movie destination