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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.hardware.automotive.evs@1.0;
     18 
     19 import types;
     20 
     21 
     22 /**
     23  * Represents a single camera and is the primary interface for capturing images.
     24  */
     25 interface IEvsDisplay {
     26 
     27     /**
     28      * Returns basic information about the EVS display provided by the system.
     29      *
     30      * See the description of the DisplayDesc structure for details.
     31      */
     32      getDisplayInfo() generates (DisplayDesc info);
     33 
     34 
     35     /**
     36      * Clients may set the display state to express their desired state.
     37      *
     38      * The HAL implementation must gracefully accept a request for any state while in
     39      * any other state, although the response may be to defer or ignore the request. The display
     40      * is defined to start in the NOT_VISIBLE state upon initialization. The client is
     41      * then expected to request the VISIBLE_ON_NEXT_FRAME state, and then begin providing
     42      * video. When the display is no longer required, the client is expected to request
     43      * the NOT_VISIBLE state after passing the last video frame.
     44      * Returns INVALID_ARG if the requested state is not a recognized value.
     45      */
     46      setDisplayState(DisplayState state) generates (EvsResult result);
     47 
     48 
     49     /**
     50      * This call requests the current state of the display
     51      *
     52      * The HAL implementation should report the actual current state, which might
     53      * transiently differ from the most recently requested state. Note, however, that
     54      * the logic responsible for changing display states should generally live above
     55      * the device layer, making it undesirable for the HAL implementation to spontaneously
     56      * change display states.
     57      */
     58      getDisplayState() generates (DisplayState state);
     59 
     60 
     61     /**
     62      * This call returns a handle to a frame buffer associated with the display.
     63      *
     64      * The returned buffer may be locked and written to by software and/or GL. This buffer
     65      * must be returned via a call to returnTargetBufferForDisplay() even if the
     66      * display is no longer visible.
     67      */
     68      getTargetBuffer() generates (BufferDesc buffer);
     69 
     70 
     71     /**
     72      * This call tells the display that the buffer is ready for display.
     73      *
     74      * The buffer is no longer valid for use by the client after this call.
     75      * There is no maximum time the caller may hold onto the buffer before making this
     76      * call. The buffer may be returned at any time and in any DisplayState, but all
     77      * buffers are expected to be returned before the IEvsDisplay interface is destroyed.
     78      */
     79     returnTargetBufferForDisplay(BufferDesc buffer) generates (EvsResult result);
     80 };
     81