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     // GPU and HWC for this frame.
49     enum CompositionType {
50         COMPOSITION_UNKNOWN = 0,
51         COMPOSITION_GPU = 1,
52         COMPOSITION_HWC = 2,
53         COMPOSITION_MIXED = COMPOSITION_GPU | COMPOSITION_HWC
54     };
55     virtual status_t prepareFrame(CompositionType compositionType) = 0;
56 
57     // Inform the surface that GPU 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 GPU 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