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WIA Minidriver Interfaces

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The WIA minidriver is a COM object that implements the standard IUnknown COM interface (which is described in the Microsoft Windows SDK documentation) and two additional WIA-specific interfaces: IStiUSD and IWiaMiniDrv.

IStiUSD Interface

The IStiUSD interface, which is defined in Stiusd.h, performs the following actions:

  • Initializes the driver when the WIA service first loads it.

  • Returns the driver's capabilities to the WIA service, reporting whether the device supports asynchronous device notifications.

  • Locks and unlocks the device for exclusive use.

IWiaMiniDrv Interface

The IWiaMiniDrv interface, which is defined in Wiamindr.h, exposes most of the WIA minidriver's functionality. This interface performs the following actions:

  • Defines the still image device's default and current settings.

  • Defines the still image device's supported commands and events.

  • Transfers data from the device to the WIA service (which ultimately passes it on to the calling application).

For more information about these interfaces, see Developing a WIA Driver: Basic Concepts.