# 拍照开发指导 ## 使用场景 使用Camera产生图片帧（拍照）。 ### 接口说明 **表1** API列表 | 类名 | 接口名 | 描述 | | -------- | -------- | -------- | | CameraKit | int32_t GetCameraIds(std::list<string> cameraList) | 获取cameraId列表 | | CameraKit | CameraAbility& GetCameraAbility(string cameraId) | 获取指定camera的能力 | | CameraKit | void RegisterCameraDeviceCallback(CameraDeviceCallback\* callback, EventHandler\* handler) | 注册camera设备状态回调 | | CameraKit | void UnregisterCameraDeviceCallback(CameraDeviceCallback\* callback) | 去注册camera设备状态回调 | | CameraKit | void CreateCamera(string cameraId, CameraStateCallback\* callback, EventHandler\* handler) | 创建camera实例 | | Camera | string GetCameraId() | 获取cameraID | | Camera | CameraConfig& GetCameraConfig() | 获取camera配置信息 | | Camera | FrameConfig& GetFrameConfig(int32_t type) | 获取捕获帧类型 | | Camera | void Configure(CameraConfig& config) | 配置camera | | Camera | void Release() | 释放camera | | Camera | int TriggerLoopingCapture(FrameConfig& frameConfig) | 开始循环帧捕获 | | Camera | void StopLoopingCapture() | 停止循环帧捕获 | | Camera | int32_t TriggerSingleCapture(FrameConfig& frameConfig) | 截图 | | CameraConfig | void SetFrameStateCallback(FrameStateCallback\* callback, EventHandler\* handler); | 设置帧状态回调 | | CameraConfig | static CameraConfig\* CreateCameraConfig() | 创建camera配置信息实例 | | CameraAbility | std::list<Size> GetSupportedSizes(int format) | 根据类型获取支持输出图像尺寸大小 | | CameraAbility | std::list<T> GetParameterRange(uint32_t key) | 获取支持的参数范围 | | CameraDevice | CameraDeviceCallback() | camera设备回调类构造函数 | | CameraDevice | void OnCameraStatus​(std::string cameraId, int32_t status) | camera设备状态变化时的回调 | | CameraStateCallback | CameraStateCallback​() | camera状态回调类构造函数 | | CameraStateCallback | void OnConfigured​(Camera& camera) | camera配置成功回调 | | CameraStateCallback | void OnConfigureFailed​(Camera& camera,int32_t errorCode) | camera配置失败回调 | | CameraStateCallback | void OnCreated​(Camera& camera) | camera创建成功回调 | | CameraStateCallback | void OnCreateFailed​(std::string cameraId,int32_t errorCode) | camera创建失败回调 | | CameraStateCallback | void OnReleased​(Camera& camera) | camera释放回调 | | FrameStateCallback | FrameStateCallback​() | 帧状态回调类构造函数 | | FrameStateCallback | void OnFrameFinished(Camera& camera, FrameConfig& frameConfig, FrameResult& frameResult) | 拍照帧完成回调 | | FrameStateCallback | void OnFrameError​(Camera& camera, FrameConfig& frameConfig, int32_t errorCode, FrameResult& frameResult) | 拍照帧异常回调 | | FrameConfig | int32_t GetFrameConfigType() | 获取帧配置类型 | | FrameConfig | std::list<OHOS::Surface> GetSurfaces() | 获取帧配置的surface | | FrameConfig | void AddSurface(OHOS::AGP::UISurface& surface); | 添加surface | | FrameConfig | void RemoveSurface(OHOS::AGP::UISurface& surface); | 删除surface | ## 约束与限制 无。 ## 开发步骤 1. 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。 ``` class SampleCameraDeviceCallback : public CameraDeviceCallback { void OnCameraStatus(std::string cameraId, int32_t status) override { //do something when camera is available/unavailable } }; ``` 2. 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。 ``` static void SampleSaveCapture(const char *p, uint32_t size) { cout << "Start saving picture" << endl; struct timeval tv; gettimeofday(&tv, NULL); struct tm *ltm = localtime(&tv.tv_sec); if (ltm != nullptr) { ostringstream ss("Capture_"); ss << "Capture" << ltm->tm_hour << "-" << ltm->tm_min << "-" << ltm->tm_sec << ".jpg"; ofstream pic("/sdcard/" + ss.str(), ofstream::out | ofstream::trunc); cout << "write " << size << " bytes" << endl; pic.write(p, size); cout << "Saving picture end" << endl; } } class TestFrameStateCallback : public FrameStateCallback { void OnFrameFinished(Camera &camera, FrameConfig &fc, FrameResult &result) override { cout << "Receive frame complete inform." << endl; if (fc.GetFrameConfigType() == FRAME_CONFIG_CAPTURE) { cout << "Capture frame received." << endl; list surfaceList = fc.GetSurfaces(); for (Surface *surface : surfaceList) { SurfaceBuffer *buffer = surface->AcquireBuffer(); if (buffer != nullptr) { char *virtAddr = static_cast(buffer->GetVirAddr()); if (virtAddr != nullptr) { SampleSaveCapture(virtAddr, buffer->GetSize()); } surface->ReleaseBuffer(buffer); } delete surface; } delete &fc; } } }; ``` 3. 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。 ``` class SampleCameraStateMng : public CameraStateCallback { public: SampleCameraStateMng() = delete; SampleCameraStateMng(EventHandler &eventHdlr) : eventHdlr_(eventHdlr) {} ~SampleCameraStateMng() { if (recordFd_ != -1) { close(recordFd_); } } void OnCreated(Camera &c) override { cout << "Sample recv OnCreate camera." << endl; auto config = CameraConfig::CreateCameraConfig(); config->SetFrameStateCallback(&fsCb_, &eventHdlr_); c.Configure(*config); cam_ = &c; } void OnCreateFailed(const std::string cameraId, int32_t errorCode) override {} void OnReleased(Camera &c) override {} }; ``` 4. 创建CameraKit，用于创建和获取camera信息。 ``` CameraKit *camKit = CameraKit::GetInstance(); list camList = camKit->GetCameraIds(); string camId; for (auto &cam : camList) { cout << "camera name:" << cam << endl; const CameraAbility *ability = camKit->GetCameraAbility(cam); /* find camera which fits user's ability */ list sizeList = ability->GetSupportedSizes(0); if (find(sizeList.begin(), sizeList.end(), CAM_PIC_1080P) != sizeList.end()) { camId = cam; break; } } ``` 5. 创建Camera实例。 ``` EventHandler eventHdlr; // Create a thread to handle callback events SampleCameraStateMng CamStateMng(eventHdlr); camKit->CreateCamera(camId, CamStateMng, eventHdlr); ``` 6. 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。 ``` void OnCreated(Camera &c) override { cout << "Sample recv OnCreate camera." << endl; auto config = CameraConfig::CreateCameraConfig(); config->SetFrameStateCallback(&fsCb_, &eventHdlr_); c.Configure(*config); cam_ = &c; } void Capture() { if (cam_ == nullptr) { cout << "Camera is not ready." << endl; return; } FrameConfig *fc = new FrameConfig(FRAME_CONFIG_CAPTURE); Surface *surface = Surface::CreateSurface(); if (surface == nullptr) { delete fc; return; } surface->SetWidthAndHeight(1920, 1080); /* 1920:width,1080:height */ fc->AddSurface(*surface); cam_->TriggerSingleCapture(*fc); } ```