harmony 鸿蒙拍照开发指导
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)|抓图。|
|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::listOHOS::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
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. } };
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<Surface *> surfaceList = fc.GetSurfaces(); for (Surface *surface : surfaceList) { SurfaceBuffer *buffer = surface->AcquireBuffer(); if (buffer != nullptr) { char *virtAddr = static_cast<char *>(buffer->GetVirAddr()); if (virtAddr != nullptr) { SampleSaveCapture(virtAddr, buffer->GetSize()); } surface->ReleaseBuffer(buffer); } delete surface; } delete &fc; } } };
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 {} };
创建CameraKit,用于创建和获取camera信息。
CameraKit *camKit = CameraKit::GetInstance(); list<string> 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<CameraPicSize> sizeList = ability->GetSupportedSizes(0); if (find(sizeList.begin(), sizeList.end(), CAM_PIC_1080P) != sizeList.end()) { camId = cam; break; } }
创建Camera实例。
EventHandler eventHdlr; // Create a thread to handle callback events. SampleCameraStateMng CamStateMng(eventHdlr); camKit->CreateCamera(camId, CamStateMng, eventHdlr);
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); }
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