IEvsDisplay

Returns basic information about the EVS display provided by the system.

See the description of the DisplayDesc structure for details.

Clients may set the display state to express their desired state.

The HAL implementation must gracefully accept a request for any state while in any other state, although the response may be to defer or ignore the request.The display is defined to start in the NOT_VISIBLE state upon initialization.The client is then expected to request the VISIBLE_ON_NEXT_FRAME state, and then begin providing video.When the display is no longer required, the client is expected to request the NOT_VISIBLE state after passing the last video frame.Returns INVALID_ARG if the requested state is not a recognized value.

This call requests the current state of the display

The HAL implementation should report the actual current state, which might transiently differ from the most recently requested state.Note, however, that the logic responsible for changing display states should generally live above the device layer, making it undesirable for the HAL implementation to spontaneously change display states.

This call returns a handle to a frame buffer associated with the display.

The returned buffer may be locked and written to by software and/or GL.This buffer must be returned via a call to returnTargetBufferForDisplay() even if the display is no longer visible.

This call tells the display that the buffer is ready for display.

The buffer is no longer valid for use by the client after this call.There is no maximum time the caller may hold onto the buffer before making this call.The buffer may be returned at any time and in any DisplayState, but all buffers are expected to be returned before the IEvsDisplay interface is destroyed.