• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1# 拍照开发指导<a name="ZH-CN_TOPIC_0000001054915940"></a>
2
3-   [使用场景](#zh-cn_topic_0000001052170554_section1963312376119)
4-   [接口说明](#zh-cn_topic_0000001052170554_section56549532016)
5-   [约束与限制](#zh-cn_topic_0000001052170554_section1165911177314)
6-   [开发步骤](#zh-cn_topic_0000001052170554_section138543918214)
7
8## 使用场景<a name="zh-cn_topic_0000001052170554_section1963312376119"></a>
9
10使用Camera产生图片帧（拍照）。
11
12## 接口说明<a name="zh-cn_topic_0000001052170554_section56549532016"></a>
13
14**表 1**  API列表
15
16| 类名  | 接口名| 描述 |
17| --------- | ------------| -------- |
18| CameraKit | int32_t GetCameraIds(std::list\<string\> cameraList)  | 获取cameraId列表。 |
19| CameraKit | CameraAbility& GetCameraAbility(string cameraId)  | 获取指定camera的能力。 |
20| CameraKit | void RegisterCameraDeviceCallback(CameraDeviceCallback* callback, EventHandler* handler)  | 注册camera设备状态回调。 |
21| CameraKit | void UnregisterCameraDeviceCallback(CameraDeviceCallback* callback)  | 去注册camera设备状态回调。 |
22| CameraKit | void CreateCamera(string cameraId, CameraStateCallback* callback, EventHandler* handler)  | 创建camera实例。 |
23| Camera | string GetCameraId()  | 获取cameraID。 |
24| Camera | CameraConfig& GetCameraConfig()  | 获取camera配置信息。 |
25| Camera | FrameConfig& GetFrameConfig(int32_t type)  | 获取捕获帧类型。 |
26| Camera | void Configure(CameraConfig& config)  | 配置camera。 |
27| Camera | void Release()  | 释放camera。 |
28| Camera | int TriggerLoopingCapture(FrameConfig& frameConfig)  | 开始循环帧捕获。 |
29| Camera | void StopLoopingCapture()  | 停止循环帧捕获。 |
30| Camera | int32_t TriggerSingleCapture(FrameConfig& frameConfig)  | 抓图。 |
31| CameraConfig | void SetFrameStateCallback(FrameStateCallback* callback, EventHandler* handler)  | 设置帧状态回调。 |
32| CameraConfig | static CameraConfig* CreateCameraConfig()  | 创建camera配置信息实例。 |
33| CameraAbility | std::list\<Size\> GetSupportedSizes(int format)  | 根据类型获取支持输出图像尺寸大小。 |
34| CameraAbility | std::list\<T\> GetParameterRange(uint32_t key)  | 获取支持的参数范围。 |
35| CameraDevice | CameraDeviceCallback()  | camera设备回调类构造函数。 |
36| CameraDevice | void OnCameraStatus​(std::string cameraId, int32_t status)  | camera设备状态变化时的回调。 |
37| CameraStateCallback | CameraStateCallback​()  | camera状态回调类构造函数。 |
38| CameraStateCallback | void OnConfigured​(Camera& camera)  | camera配置成功回调。 |
39| CameraStateCallback | void OnConfigureFailed​(Camera& camera,int32_t errorCode)  | camera配置失败回调。 |
40| CameraStateCallback | void OnCreated​(Camera& camera)  | camera创建成功回调。 |
41| CameraStateCallback | void OnCreateFailed​(std::string cameraId,int32_t errorCode)  | camera创建失败回调。 |
42| CameraStateCallback | void OnReleased​(Camera& camera)  | camera释放回调。 |
43| FrameStateCallback | FrameStateCallback​()  | 帧状态回调类构造函数。 |
44| FrameStateCallback | void OnFrameFinished(Camera& camera, FrameConfig& frameConfig, FrameResult& frameResult)  | 拍照帧完成回调。 |
45| FrameStateCallback | void OnFrameError​(Camera& camera, FrameConfig& frameConfig, int32_t errorCode, FrameResult& frameResult)  | 拍照帧异常回调。 |
46| FrameConfig | int32_t GetFrameConfigType()  | 获取帧配置类型。 |
47| FrameConfig | std::list<OHOS::Surface> GetSurfaces()  | 获取帧配置的surface。 |
48| FrameConfig | void AddSurface(OHOS::AGP::UISurface& surface)  | 添加surface。 |
49| FrameConfig | void RemoveSurface(OHOS::AGP::UISurface& surface)  | 删除surface。 |
50
51## 约束与限制<a name="zh-cn_topic_0000001052170554_section1165911177314"></a>
52
53无。
54
55## 开发步骤<a name="zh-cn_topic_0000001052170554_section138543918214"></a>
56
571.  <a name="zh-cn_topic_0000001052170554_li378084192111"></a>实现设备状态回调的派生类，用户在设备状态发生变更（如新插入相机设备/相机掉线）时，自定义操作。
58
59    ```
60    class SampleCameraDeviceCallback : public CameraDeviceCallback {
61        void OnCameraStatus(std::string cameraId, int32_t status) override
62        {
63            //do something when camera is available/unavailable.
64        }
65    };
66    ```
67
682.  <a name="zh-cn_topic_0000001052170554_li8716104682913"></a>实现帧事件回调的派生类，这里在拿到帧数据以后将其转存为文件。
69
70    ```
71    static void SampleSaveCapture(const char *p, uint32_t size)
72    {
73        cout << "Start saving picture" << endl;
74        struct timeval tv;
75        gettimeofday(&tv, NULL);
76        struct tm *ltm = localtime(&tv.tv_sec);
77        if (ltm != nullptr) {
78            ostringstream ss("Capture_");
79            ss << "Capture" << ltm->tm_hour << "-" << ltm->tm_min << "-" << ltm->tm_sec << ".jpg";
80
81            ofstream pic("/sdcard/" + ss.str(), ofstream::out | ofstream::trunc);
82            cout << "write " << size << " bytes" << endl;
83            pic.write(p, size);
84            cout << "Saving picture end" << endl;
85        }
86    }
87
88    class TestFrameStateCallback : public FrameStateCallback {
89        void OnFrameFinished(Camera &camera, FrameConfig &fc, FrameResult &result) override
90        {
91            cout << "Receive frame complete inform." << endl;
92            if (fc.GetFrameConfigType() == FRAME_CONFIG_CAPTURE) {
93                cout << "Capture frame received." << endl;
94                list<Surface *> surfaceList = fc.GetSurfaces();
95                for (Surface *surface : surfaceList) {
96                    SurfaceBuffer *buffer = surface->AcquireBuffer();
97                    if (buffer != nullptr) {
98                        char *virtAddr = static_cast<char *>(buffer->GetVirAddr());
99                        if (virtAddr != nullptr) {
100                            SampleSaveCapture(virtAddr, buffer->GetSize());
101                        }
102                        surface->ReleaseBuffer(buffer);
103                    }
104                    delete surface;
105                }
106                delete &fc;
107            }
108        }
109    };
110    ```
111
1123.  <a name="zh-cn_topic_0000001052170554_li6671035102514"></a>实现相机状态回调的派生类，自定义相机状态发生变化（配置成功/失败，创建成功/失败\)时的操作。
113
114    ```
115    class SampleCameraStateMng : public CameraStateCallback {
116    public:
117        SampleCameraStateMng() = delete;
118        SampleCameraStateMng(EventHandler &eventHdlr) : eventHdlr_(eventHdlr) {}
119        ~SampleCameraStateMng()
120        {
121            if (recordFd_ != -1) {
122                close(recordFd_);
123            }
124        }
125        void OnCreated(Camera &c) override
126        {
127            cout << "Sample recv OnCreate camera." << endl;
128            auto config = CameraConfig::CreateCameraConfig();
129            config->SetFrameStateCallback(&fsCb_, &eventHdlr_);
130            c.Configure(*config);
131            cam_ = &c;
132        }
133        void OnCreateFailed(const std::string cameraId, int32_t errorCode) override {}
134        void OnReleased(Camera &c) override {}
135    };
136    ```
137
1384.  创建CameraKit，用于创建和获取camera信息。
139
140    ```
141    CameraKit *camKit = CameraKit::GetInstance();
142    list<string> camList = camKit->GetCameraIds();
143    string camId;
144    for (auto &cam : camList) {
145        cout << "camera name:" << cam << endl;
146        const CameraAbility *ability = camKit->GetCameraAbility(cam);
147        /* find camera which fits user's ability */
148        list<CameraPicSize> sizeList = ability->GetSupportedSizes(0);
149        if (find(sizeList.begin(), sizeList.end(), CAM_PIC_1080P) != sizeList.end()) {
150            camId = cam;
151            break;
152        }
153    }
154    ```
155
1565.  创建Camera实例。
157
158    ```
159    EventHandler eventHdlr; // Create a thread to handle callback events.
160    SampleCameraStateMng CamStateMng(eventHdlr);
161
162    camKit->CreateCamera(camId, CamStateMng, eventHdlr);
163    ```
164
1656.  根据[步骤1](#zh-cn_topic_0000001052170554_li378084192111)、[步骤2](#zh-cn_topic_0000001052170554_li8716104682913)、[步骤3](#zh-cn_topic_0000001052170554_li6671035102514)中的回调设计，同步等待 OnCreated 回调拿到 cam\_ 之后，进行相关操作。
166
167    ```
168    void OnCreated(Camera &c) override
169    {
170        cout << "Sample recv OnCreate camera." << endl;
171        auto config = CameraConfig::CreateCameraConfig();
172        config->SetFrameStateCallback(&fsCb_, &eventHdlr_);
173        c.Configure(*config);
174        cam_ = &c;
175    }
176
177    void Capture()
178    {
179        if (cam_ == nullptr) {
180            cout << "Camera is not ready." << endl;
181            return;
182        }
183        FrameConfig *fc = new FrameConfig(FRAME_CONFIG_CAPTURE);
184        Surface *surface = Surface::CreateSurface();
185        if (surface == nullptr) {
186            delete fc;
187            return;
188        }
189        surface->SetWidthAndHeight(1920, 1080); /* 1920:width,1080:height */
190        fc->AddSurface(*surface);
191        cam_->TriggerSingleCapture(*fc);
192    }
193    ```
194
195
196