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) | 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
- 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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