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1 #pragma once
2 /*
3  * Copyright (C) 2017 The Android Open Source Project
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *      http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 
18 #include <memory>
19 
20 #include "common/vsoc/lib/typed_region_view.h"
21 #include "common/vsoc/shm/graphics.h"
22 #include "common/vsoc/shm/screen_layout.h"
23 #include "uapi/vsoc_shm.h"
24 
25 namespace vsoc {
26 namespace screen {
27 
28 // Provides information related to the device's screen. Allows to query screen
29 // properties such as resolution and dpi, as well as subscribe/notify to/of
30 // changes on the screen contents. It also holds the contents of the display.
31 class ScreenRegionView
32     : public vsoc::TypedRegionView<ScreenRegionView,
33                                    vsoc::layout::screen::ScreenLayout> {
34  public:
35   static int align(int input, int alignment = kAlignment) {
36     return (input + alignment - 1) & -alignment;
37   }
38 
39   // Screen width in pixels
x_res()40   int x_res() const { return data().x_res; }
41 
42   // Screen height in pixels
y_res()43   int y_res() const { return data().y_res; }
44 
45   // Dots per inch
dpi()46   int dpi() const { return data().dpi; }
47 
48   // Refresh rate in Hertz
refresh_rate_hz()49   int refresh_rate_hz() const { return data().refresh_rate_hz; }
50 
pixel_format()51   uint32_t pixel_format() const { return kFbPixelFormat; }
52 
bytes_per_pixel()53   uint32_t bytes_per_pixel() const {
54     return vsoc::PixelFormatProperties<kFbPixelFormat>::bytes_per_pixel;
55   }
56 
line_length()57   int line_length() const { return align(x_res() * bytes_per_pixel()); }
58 
buffer_size()59   size_t buffer_size() const {
60     return (align(x_res() * bytes_per_pixel()) * y_res()) + kSwiftShaderPadding;
61   }
62 
63   int number_of_buffers() const;
64 
65   // Gets a pointer to the beginning of a buffer. Does not perform any bound
66   // checks on the index.
67   void* GetBuffer(int buffer_idx);
68 
69   // Broadcasts a new frame.
70   // buffer_idx is the index of the buffer containing the composed screen, it's
71   // a number in the range [0, number_of_buffers() - 1].
72   // Stats holds performance information of the last composition, can be null.
73   void BroadcastNewFrame(
74       int buffer_idx,
75       const vsoc::layout::screen::CompositionStats* stats = nullptr);
76 
77   // Waits for a new frame (one with a different seq_num than last one we saw).
78   // Returns the index of the buffer containing the new frame or a negative
79   // number if there was an error, stores the new sequential number in
80   // *last_seq_num. The frame sequential numbers will be provided by the
81   // hwcomposer and expected to increase monotonically over time (though it's
82   // not a hard requirement), this numbers are guaranteed to be non-zero when a
83   // valid frame is available. Performance statistics are returned through the
84   // stats parameter when it's not null.
85   int WaitForNewFrameSince(
86       uint32_t* last_seq_num,
87       vsoc::layout::screen::CompositionStats* stats = nullptr);
88 
89   using Pixel = uint32_t;
90   static constexpr int kSwiftShaderPadding = 4;
91   static constexpr int kRedShift = 0;
92   static constexpr int kGreenShift = 8;
93   static constexpr int kBlueShift = 16;
94   static constexpr int kRedBits = 8;
95   static constexpr int kGreenBits = 8;
96   static constexpr int kBlueBits = 8;
97   static constexpr uint32_t kFbPixelFormat = vsoc::VSOC_PIXEL_FORMAT_RGBA_8888;
98   static constexpr int kAlignment = 16;
99 
100  protected:
101   const uint8_t* first_buffer() const;
102 };
103 }  // namespace screen
104 }  // namespace vsoc
105