WIA Transfer Architecture
Stream-based transfers simplify transfers for drivers and driver developers. With in-memory and file transfers, the caller had to specify which transfer type to use and the driver had to perform different actions depending on which transfer type was chosen. With stream-based transfers, the caller does not need to specify memory or file transfers; the caller specifies only which stream to use, and the driver behaves the same way whether this stream is a file stream or memory stream. Using streams also provides easy integration with the WIA Image Processing Filter.
Like the other WIA application programming interfaces (APIs) and device driver interfaces (DDIs), IStream is based on the Component Object Model (COM). To ensure that stream transfers are compatible with other streams, the IWiaTransfer interface must be exposed.
The IWiaTransfer interface has methods that enable progress display during a transfer, transfer cancellation, integration of error and status reporting, and uploads and downloads of data from a device. The IWiaTransfer interface is available only through the IWiaItem2 interface. For more information about the IWiaItem2 or IWiaTransfer interfaces and their methods, see the Microsoft Windows SDK documentation.
This section includes: