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

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。

```

1. class SampleCameraDeviceCallback : public CameraDeviceCallback {
2. void OnCameraStatus(std::string cameraId, int32_t status) override
3. {
4. //do something when camera is available/unavailable
5. }
6. }; ```
7. 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。

```

1. static void SampleSaveCapture(const char *p, uint32_t size)
2. {
3. cout << "Start saving picture" << endl;
4. struct timeval tv;
5. gettimeofday(&tv, NULL);
6. struct tm *ltm = localtime(&tv.tv_sec);
7. if (ltm != nullptr) {
8. ostringstream ss("Capture_");

9. ss << "Capture" << ltm->tm_hour << "-" << ltm->tm_min << "-" << ltm->tm_sec << ".jpg";

10. ofstream pic("/sdcard/" + ss.str(), ofstream::out | ofstream::trunc);

11. cout << "write " << size << " bytes" << endl;
12. pic.write(p, size);
13. cout << "Saving picture end" << endl;
14. }

15. }

16. class TestFrameStateCallback : public FrameStateCallback {

17. void OnFrameFinished(Camera &camera, FrameConfig &fc, FrameResult &result) override
18. {
19. cout << "Receive frame complete inform." << endl;
20. if (fc.GetFrameConfigType() == FRAME_CONFIG_CAPTURE) {
21. cout << "Capture frame received." << endl;
22. list surfaceList = fc.GetSurfaces();
23. for (Surface *surface : surfaceList) {
24. SurfaceBuffer *buffer = surface->AcquireBuffer();
25. if (buffer != nullptr) {
26. char *virtAddr = static_cast(buffer->GetVirAddr());
27. if (virtAddr != nullptr) {
28. SampleSaveCapture(virtAddr, buffer->GetSize());
29. }
30. surface->ReleaseBuffer(buffer);
31. }
32. delete surface;
33. }
34. delete &fc;
35. }
36. }
37. }; ```
38. 实现相机状态回调的派生类，当相机状态发生变化（配置成功/失败，创建成功/失败)时，自定义操作。

```

1. class SampleCameraStateMng : public CameraStateCallback {
2. public:
3. SampleCameraStateMng() = delete;
4. SampleCameraStateMng(EventHandler &eventHdlr) : eventHdlr_(eventHdlr) {}
5. ~SampleCameraStateMng()
6. {
7. if (recordFd_ != -1) {
8. close(recordFd_);
9. }
10. }
11. void OnCreated(Camera &c) override
12. {
13. cout << "Sample recv OnCreate camera." << endl;
14. auto config = CameraConfig::CreateCameraConfig();
15. config->SetFrameStateCallback(&fsCb_, &eventHdlr_);
16. c.Configure(*config);
17. cam_ = &c;
18. }
19. void OnCreateFailed(const std::string cameraId, int32_t errorCode) override {}
20. void OnReleased(Camera &c) override {}
21. }; ```
22. 创建CameraKit，用于创建和获取camera信息。

```

1. CameraKit *camKit = CameraKit::GetInstance();
2. list camList = camKit->GetCameraIds();
3. string camId;
4. for (auto &cam : camList) {
5. cout << "camera name:" << cam << endl;
6. const CameraAbility *ability = camKit->GetCameraAbility(cam);
7. / find camera which fits user's ability /
8. list sizeList = ability->GetSupportedSizes(0);
9. if (find(sizeList.begin(), sizeList.end(), CAM_PIC_1080P) != sizeList.end()) {
10. camId = cam;
11. break;
12. }
13. } ```
14. 创建Camera实例。

```

1. EventHandler eventHdlr; // Create a thread to handle callback events

2. SampleCameraStateMng CamStateMng(eventHdlr);

3. camKit->CreateCamera(camId, CamStateMng, eventHdlr); ```

4. 根据步骤1、步骤2、步骤3中的回调设计，camera实例创建成功后会进行配置操作，主流程中app需要设计同步机制。

```

1. void OnCreated(Camera &c) override
2. {
3. cout << "Sample recv OnCreate camera." << endl;
4. auto config = CameraConfig::CreateCameraConfig();
5. config->SetFrameStateCallback(&fsCb_, &eventHdlr_);
6. c.Configure(*config);
7. cam_ = &c;

8. }

9. void Capture()

10. {
11. if (cam_ == nullptr) {
12. cout << "Camera is not ready." << endl;
13. return;
14. }
15. FrameConfig *fc = new FrameConfig(FRAME_CONFIG_CAPTURE);
16. Surface *surface = Surface::CreateSurface();
17. if (surface == nullptr) {
18. delete fc;
19. }
20. surface->SetWidthAndHeight(1920, 1080); / 1920:width,1080:height /
21. fc->AddSurface(*surface);
22. cam_->TriggerSingleCapture(*fc);
23. } ```