1# 拍照开发指导 2 3 4## 使用场景 5 6使用Camera产生图片帧（拍照）。 7 8 9### 接口说明 10 11 **表1** API列表 12 13| 类名 | 接口名 | 描述 | 14| -------- | -------- | -------- | 15| CameraKit | int32_t GetCameraIds(std::list<string> cameraList) | 获取cameraId列表 | 16| CameraKit | CameraAbility& GetCameraAbility(string cameraId) | 获取指定camera的能力 | 17| CameraKit | void RegisterCameraDeviceCallback(CameraDeviceCallback\* callback, EventHandler\* handler) | 注册camera设备状态回调 | 18| CameraKit | void UnregisterCameraDeviceCallback(CameraDeviceCallback\* callback) | 去注册camera设备状态回调 | 19| CameraKit | void CreateCamera(string cameraId, CameraStateCallback\* callback, EventHandler\* handler) | 创建camera实例 | 20| Camera | string GetCameraId() | 获取cameraID | 21| Camera | CameraConfig& GetCameraConfig() | 获取camera配置信息 | 22| Camera | FrameConfig& GetFrameConfig(int32_t type) | 获取捕获帧类型 | 23| Camera | void Configure(CameraConfig& config) | 配置camera | 24| Camera | void Release() | 释放camera | 25| Camera | int TriggerLoopingCapture(FrameConfig& frameConfig) | 开始循环帧捕获 | 26| Camera | void StopLoopingCapture() | 停止循环帧捕获 | 27| Camera | int32_t TriggerSingleCapture(FrameConfig& frameConfig) | 截图 | 28| CameraConfig | void SetFrameStateCallback(FrameStateCallback\* callback, EventHandler\* handler); | 设置帧状态回调 | 29| CameraConfig | static CameraConfig\* CreateCameraConfig() | 创建camera配置信息实例 | 30| CameraAbility | std::list<Size> GetSupportedSizes(int format) | 根据类型获取支持输出图像尺寸大小 | 31| CameraAbility | std::list<T> GetParameterRange(uint32_t key) | 获取支持的参数范围 | 32| CameraDevice | CameraDeviceCallback() | camera设备回调类构造函数 | 33| CameraDevice | void OnCameraStatus(std::string cameraId, int32_t status) | camera设备状态变化时的回调 | 34| CameraStateCallback | CameraStateCallback() | camera状态回调类构造函数 | 35| CameraStateCallback | void OnConfigured(Camera& camera) | camera配置成功回调 | 36| CameraStateCallback | void OnConfigureFailed(Camera& camera,int32_t errorCode) | camera配置失败回调 | 37| CameraStateCallback | void OnCreated(Camera& camera) | camera创建成功回调 | 38| CameraStateCallback | void OnCreateFailed(std::string cameraId,int32_t errorCode) | camera创建失败回调 | 39| CameraStateCallback | void OnReleased(Camera& camera) | camera释放回调 | 40| FrameStateCallback | FrameStateCallback() | 帧状态回调类构造函数 | 41| FrameStateCallback | void OnFrameFinished(Camera& camera, FrameConfig& frameConfig, FrameResult& frameResult) | 拍照帧完成回调 | 42| FrameStateCallback | void OnFrameError(Camera& camera, FrameConfig& frameConfig, int32_t errorCode, FrameResult& frameResult) | 拍照帧异常回调 | 43| FrameConfig | int32_t GetFrameConfigType() | 获取帧配置类型 | 44| FrameConfig | std::list<OHOS::Surface> GetSurfaces() | 获取帧配置的surface | 45| FrameConfig | void AddSurface(OHOS::AGP::UISurface& surface); | 添加surface | 46| FrameConfig | void RemoveSurface(OHOS::AGP::UISurface& surface); | 删除surface | 47 48 49## 约束与限制 50 51无。 52 53 54## 开发步骤 55 561. 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。 57 58 ``` 59 class SampleCameraDeviceCallback : public CameraDeviceCallback { 60 void OnCameraStatus(std::string cameraId, int32_t status) override 61 { 62 //do something when camera is available/unavailable 63 } 64 }; 65 ``` 66 672. 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。 68 69 ``` 70 static void SampleSaveCapture(const char *p, uint32_t size) 71 { 72 cout << "Start saving picture" << endl; 73 struct timeval tv; 74 gettimeofday(&tv, NULL); 75 struct tm *ltm = localtime(&tv.tv_sec); 76 if (ltm != nullptr) { 77 ostringstream ss("Capture_"); 78 ss << "Capture" << ltm->tm_hour << "-" << ltm->tm_min << "-" << ltm->tm_sec << ".jpg"; 79 80 ofstream pic("/sdcard/" + ss.str(), ofstream::out | ofstream::trunc); 81 cout << "write " << size << " bytes" << endl; 82 pic.write(p, size); 83 cout << "Saving picture end" << endl; 84 } 85 } 86 87 class TestFrameStateCallback : public FrameStateCallback { 88 void OnFrameFinished(Camera &camera, FrameConfig &fc, FrameResult &result) override 89 { 90 cout << "Receive frame complete inform." << endl; 91 if (fc.GetFrameConfigType() == FRAME_CONFIG_CAPTURE) { 92 cout << "Capture frame received." << endl; 93 list<Surface *> surfaceList = fc.GetSurfaces(); 94 for (Surface *surface : surfaceList) { 95 SurfaceBuffer *buffer = surface->AcquireBuffer(); 96 if (buffer != nullptr) { 97 char *virtAddr = static_cast<char *>(buffer->GetVirAddr()); 98 if (virtAddr != nullptr) { 99 SampleSaveCapture(virtAddr, buffer->GetSize()); 100 } 101 surface->ReleaseBuffer(buffer); 102 } 103 delete surface; 104 } 105 delete &fc; 106 } 107 } 108 }; 109 ``` 110 1113. 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。 112 113 ``` 114 class SampleCameraStateMng : public CameraStateCallback { 115 public: 116 SampleCameraStateMng() = delete; 117 SampleCameraStateMng(EventHandler &eventHdlr) : eventHdlr_(eventHdlr) {} 118 ~SampleCameraStateMng() 119 { 120 if (recordFd_ != -1) { 121 close(recordFd_); 122 } 123 } 124 void OnCreated(Camera &c) override 125 { 126 cout << "Sample recv OnCreate camera." << endl; 127 auto config = CameraConfig::CreateCameraConfig(); 128 config->SetFrameStateCallback(&fsCb_, &eventHdlr_); 129 c.Configure(*config); 130 cam_ = &c; 131 } 132 void OnCreateFailed(const std::string cameraId, int32_t errorCode) override {} 133 void OnReleased(Camera &c) override {} 134 }; 135 ``` 136 1374. 创建CameraKit，用于创建和获取camera信息。 138 139 ``` 140 CameraKit *camKit = CameraKit::GetInstance(); 141 list<string> camList = camKit->GetCameraIds(); 142 string camId; 143 for (auto &cam : camList) { 144 cout << "camera name:" << cam << endl; 145 const CameraAbility *ability = camKit->GetCameraAbility(cam); 146 /* find camera which fits user's ability */ 147 list<CameraPicSize> sizeList = ability->GetSupportedSizes(0); 148 if (find(sizeList.begin(), sizeList.end(), CAM_PIC_1080P) != sizeList.end()) { 149 camId = cam; 150 break; 151 } 152 } 153 ``` 154 1555. 创建Camera实例。 156 157 ``` 158 EventHandler eventHdlr; // Create a thread to handle callback events 159 SampleCameraStateMng CamStateMng(eventHdlr); 160 161 camKit->CreateCamera(camId, CamStateMng, eventHdlr); 162 ``` 163 1646. 根据步骤1、步骤2、步骤3中的回调设计，同步等待 OnCreated 回调拿到 cam_ 之后，进行相关操作。 165 166 ``` 167 void OnCreated(Camera &c) override 168 { 169 cout << "Sample recv OnCreate camera." << endl; 170 auto config = CameraConfig::CreateCameraConfig(); 171 config->SetFrameStateCallback(&fsCb_, &eventHdlr_); 172 c.Configure(*config); 173 cam_ = &c; 174 } 175 176 void Capture() 177 { 178 if (cam_ == nullptr) { 179 cout << "Camera is not ready." << endl; 180 return; 181 } 182 FrameConfig *fc = new FrameConfig(FRAME_CONFIG_CAPTURE); 183 Surface *surface = Surface::CreateSurface(); 184 if (surface == nullptr) { 185 delete fc; 186 return; 187 } 188 surface->SetWidthAndHeight(1920, 1080); /* 1920:width,1080:height */ 189 fc->AddSurface(*surface); 190 cam_->TriggerSingleCapture(*fc); 191 } 192 ``` 193