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      1 /*
      2  * Copyright 2013 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 #pragma once
     18 
     19 #include <utils/Errors.h>
     20 #include <utils/RefBase.h>
     21 #include <utils/StrongPointer.h>
     22 
     23 namespace android {
     24 
     25 class Fence;
     26 class IGraphicBufferProducer;
     27 class String8;
     28 
     29 namespace compositionengine {
     30 
     31 /**
     32  * An abstraction for working with a display surface (buffer queue)
     33  */
     34 class DisplaySurface : public virtual RefBase {
     35 public:
     36     virtual ~DisplaySurface();
     37 
     38     // beginFrame is called at the beginning of the composition loop, before
     39     // the configuration is known. The DisplaySurface should do anything it
     40     // needs to do to enable HWComposer to decide how to compose the frame.
     41     // We pass in mustRecompose so we can keep VirtualDisplaySurface's state
     42     // machine happy without actually queueing a buffer if nothing has changed.
     43     virtual status_t beginFrame(bool mustRecompose) = 0;
     44 
     45     // prepareFrame is called after the composition configuration is known but
     46     // before composition takes place. The DisplaySurface can use the
     47     // composition type to decide how to manage the flow of buffers between
     48     // GLES and HWC for this frame.
     49     enum CompositionType {
     50         COMPOSITION_UNKNOWN = 0,
     51         COMPOSITION_GLES = 1,
     52         COMPOSITION_HWC = 2,
     53         COMPOSITION_MIXED = COMPOSITION_GLES | COMPOSITION_HWC
     54     };
     55     virtual status_t prepareFrame(CompositionType compositionType) = 0;
     56 
     57     // Inform the surface that GLES composition is complete for this frame, and
     58     // the surface should make sure that HWComposer has the correct buffer for
     59     // this frame. Some implementations may only push a new buffer to
     60     // HWComposer if GLES composition took place, others need to push a new
     61     // buffer on every frame.
     62     //
     63     // advanceFrame must be followed by a call to  onFrameCommitted before
     64     // advanceFrame may be called again.
     65     virtual status_t advanceFrame() = 0;
     66 
     67     // onFrameCommitted is called after the frame has been committed to the
     68     // hardware composer. The surface collects the release fence for this
     69     // frame's buffer.
     70     virtual void onFrameCommitted() = 0;
     71 
     72     virtual void dumpAsString(String8& result) const = 0;
     73 
     74     virtual void resizeBuffers(const uint32_t w, const uint32_t h) = 0;
     75 
     76     virtual const sp<Fence>& getClientTargetAcquireFence() const = 0;
     77 };
     78 
     79 } // namespace compositionengine
     80 } // namespace android
     81