# 拍照开发指导 - [使用场景](#zh-cn_topic_0000001052170554_section1963312376119) - [接口说明](#zh-cn_topic_0000001052170554_section56549532016) - [约束与限制](#zh-cn_topic_0000001052170554_section1165911177314) - [开发步骤](#zh-cn_topic_0000001052170554_section138543918214) ## 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::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](#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。 ``` 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); } ```