Photo Capture Practices (C/C++)
Before developing a camera application, you must request required permissions.
This topic provides sample code that covers the complete photo capture process and the API calling sequence. For details about a single process (such as device input, session management, and photo capture), see the corresponding C/C++ development guide links provided in Requesting Camera Development Permissions.
Development Process
After obtaining the output stream capabilities supported by the camera, create a photo stream. The development process is as follows:
Complete Sample Code
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Link the dynamic library in the CMake script.
target_link_libraries(entry PUBLIC libace_napi.z.so libhilog_ndk.z.so libnative_buffer.so libohcamera.so libohimage.so libohfileuri.so ) -
Create the header file ndk_camera.h.
#include "ohcamera/camera.h" #include "ohcamera/camera_input.h" #include "ohcamera/capture_session.h" #include "ohcamera/photo_output.h" #include "ohcamera/preview_output.h" #include "ohcamera/video_output.h" #include "ohcamera/camera_manager.h" class NDKCamera { public: ~NDKCamera(); NDKCamera(char* previewId); Camera_ErrorCode RegisterBufferCb(void* cb); }; -
Import the NDK APIs on the C++ side, and perform photo capture based on the surface ID passed in.
#include "hilog/log.h" void CaptureSessionOnFocusStateChange(Camera_CaptureSession* session, Camera_FocusState focusState) { OH_LOG_INFO(LOG_APP, "CaptureSessionOnFocusStateChange"); } void CaptureSessionOnError(Camera_CaptureSession* session, Camera_ErrorCode errorCode) { OH_LOG_INFO(LOG_APP, "CaptureSessionOnError = %{public}d", errorCode); } CaptureSession_Callbacks* GetCaptureSessionRegister(void) { static CaptureSession_Callbacks captureSessionCallbacks = { .onFocusStateChange = CaptureSessionOnFocusStateChange, .onError = CaptureSessionOnError }; return &captureSessionCallbacks; } void PreviewOutputOnFrameStart(Camera_PreviewOutput* previewOutput) { OH_LOG_INFO(LOG_APP, "PreviewOutputOnFrameStart"); } void PreviewOutputOnFrameEnd(Camera_PreviewOutput* previewOutput, int32_t frameCount) { OH_LOG_INFO(LOG_APP, "PreviewOutputOnFrameEnd = %{public}d", frameCount); } void PreviewOutputOnError(Camera_PreviewOutput* previewOutput, Camera_ErrorCode errorCode) { OH_LOG_INFO(LOG_APP, "PreviewOutputOnError = %{public}d", errorCode); } PreviewOutput_Callbacks* GetPreviewOutputListener(void) { static PreviewOutput_Callbacks previewOutputListener = { .onFrameStart = PreviewOutputOnFrameStart, .onFrameEnd = PreviewOutputOnFrameEnd, .onError = PreviewOutputOnError }; return &previewOutputListener; } void OnCameraInputError(const Camera_Input* cameraInput, Camera_ErrorCode errorCode) { OH_LOG_INFO(LOG_APP, "OnCameraInput errorCode = %{public}d", errorCode); } CameraInput_Callbacks* GetCameraInputListener(void) { static CameraInput_Callbacks cameraInputCallbacks = { .onError = OnCameraInputError }; return &cameraInputCallbacks; } void CameraManagerStatusCallback(Camera_Manager* cameraManager, Camera_StatusInfo* status) { OH_LOG_INFO(LOG_APP, "CameraManagerStatusCallback is called"); } CameraManager_Callbacks* GetCameraManagerListener() { static CameraManager_Callbacks cameraManagerListener = { .onCameraStatus = CameraManagerStatusCallback }; return &cameraManagerListener; } static void* bufferCb = nullptr; Camera_ErrorCode NDKCamera::RegisterBufferCb(void* cb) { OH_LOG_INFO(LOG_APP, " RegisterBufferCb start"); if (cb == nullptr) { OH_LOG_INFO(LOG_APP, " RegisterBufferCb invalid error"); return CAMERA_INVALID_ARGUMENT; } bufferCb = cb; return CAMERA_OK; } void OnPhotoAvailable(Camera_PhotoOutput* photoOutput, OH_PhotoNative* photo) { OH_LOG_INFO(LOG_APP, "OnPhotoAvailable start!"); OH_ImageNative* imageNative; Camera_ErrorCode errCode = OH_PhotoNative_GetMainImage(photo, &imageNative); OH_LOG_INFO(LOG_APP, "OnPhotoAvailable errCode:%{public}d imageNative:%{public}p", errCode, imageNative); // Read the size attribute of OH_ImageNative. Image_Size size; Image_ErrorCode imageErr = OH_ImageNative_GetImageSize(imageNative, &size); OH_LOG_INFO(LOG_APP, "OnPhotoAvailable imageErr:%{public}d width:%{public}d height:%{public}d", imageErr, size.width, size.height); // Read the number of elements in the component list of OH_ImageNative. size_t componentTypeSize = 0; imageErr = OH_ImageNative_GetComponentTypes(imageNative, nullptr, &componentTypeSize); OH_LOG_INFO(LOG_APP, "OnPhotoAvailable imageErr:%{public}d componentTypeSize:%{public}zu", imageErr, componentTypeSize); // Read the component list of OH_ImageNative. uint32_t* components = new uint32_t[componentTypeSize]; imageErr = OH_ImageNative_GetComponentTypes(imageNative, &components, &componentTypeSize); OH_LOG_INFO(LOG_APP, "OnPhotoAvailable OH_ImageNative_GetComponentTypes imageErr:%{public}d", imageErr); // Read the buffer object corresponding to the first component of OH_ImageNative. OH_NativeBuffer* nativeBuffer = nullptr; imageErr = OH_ImageNative_GetByteBuffer(imageNative, components[0], &nativeBuffer); OH_LOG_INFO(LOG_APP, "OnPhotoAvailable OH_ImageNative_GetByteBuffer imageErr:%{public}d", imageErr); // Read the size of the buffer corresponding to the first component of OH_ImageNative. size_t nativeBufferSize = 0; imageErr = OH_ImageNative_GetBufferSize(imageNative, components[0], &nativeBufferSize); OH_LOG_INFO(LOG_APP, "OnPhotoAvailable imageErr:%{public}d nativeBufferSize:%{public}zu", imageErr, nativeBufferSize); // Read the row stride corresponding to the first component of OH_ImageNative. int32_t rowStride = 0; imageErr = OH_ImageNative_GetRowStride(imageNative, components[0], &rowStride); OH_LOG_INFO(LOG_APP, "OnPhotoAvailable imageErr:%{public}d rowStride:%{public}d", imageErr, rowStride); // Read the pixel stride corresponding to the first component of OH_ImageNative. int32_t pixelStride = 0; imageErr = OH_ImageNative_GetPixelStride(imageNative, components[0], &pixelStride); OH_LOG_INFO(LOG_APP, "OnPhotoAvailable imageErr:%{public}d pixelStride:%{public}d", imageErr, pixelStride); // Map the ION memory to the process address space. void* virAddr = nullptr; // Point to the virtual address of the mapped memory. After unmapping, the pointer is invalid. int32_t ret = OH_NativeBuffer_Map(nativeBuffer, &virAddr); // After mapping, the start address of the memory is returned through the parameter virAddr. OH_LOG_INFO(LOG_APP, "OnPhotoAvailable OH_NativeBuffer_Map err:%{public}d", ret); // Pass the processed buffer to the ArkTS side through the callback for image display or storage (using a security component). For details, see Photo Capture (C/C++). if (bufferCb == nullptr) { OH_LOG_INFO(LOG_APP, "Current bufferCb invalid error"); return; } auto cb = (void (*)(void *, size_t))(bufferCb); cb(virAddr, nativeBufferSize); // After the processing is complete, unmap and release the buffer. ret = OH_NativeBuffer_Unmap(nativeBuffer); if (ret != 0) { OH_LOG_ERROR(LOG_APP, "OnPhotoAvailable OH_NativeBuffer_Unmap error:%{public}d", ret); } } NDKCamera::NDKCamera(char* previewId) { Camera_Manager* cameraManager = nullptr; Camera_Device* cameras = nullptr; Camera_CaptureSession* captureSession = nullptr; Camera_OutputCapability* cameraOutputCapability = nullptr; const Camera_Profile* previewProfile = nullptr; const Camera_Profile* photoProfile = nullptr; Camera_PreviewOutput* previewOutput = nullptr; Camera_PhotoOutput* photoOutput = nullptr; Camera_Input* cameraInput = nullptr; uint32_t size = 0; uint32_t cameraDeviceIndex = 0; char* previewSurfaceId = previewId; // Create a CameraManager object. Camera_ErrorCode ret = OH_Camera_GetCameraManager(&cameraManager); if (cameraManager == nullptr || ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_Camera_GetCameraMananger failed."); return; } // Listen for camera status changes. ret = OH_CameraManager_RegisterCallback(cameraManager, GetCameraManagerListener()); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CameraManager_RegisterCallback failed."); } // Obtain the camera list. ret = OH_CameraManager_GetSupportedCameras(cameraManager, &cameras, &size); if (cameras == nullptr || size <= 0 || ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedCameras failed."); return; } if (size < cameraDeviceIndex + 1) { OH_LOG_ERROR(LOG_APP, "cameraDeviceIndex is invalid."); return; } // Create a camera input stream. ret = OH_CameraManager_CreateCameraInput(cameraManager, &cameras[cameraDeviceIndex], &cameraInput); if (cameraInput == nullptr || ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateCameraInput failed."); return; } // Listen for camera input errors. ret = OH_CameraInput_RegisterCallback(cameraInput, GetCameraInputListener()); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CameraInput_RegisterCallback failed."); return; } // Open the camera. ret = OH_CameraInput_Open(cameraInput); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CameraInput_Open failed."); return; } // Obtain the output stream capability supported by the camera. ret = OH_CameraManager_GetSupportedCameraOutputCapability(cameraManager, &cameras[cameraDeviceIndex], &cameraOutputCapability); if (cameraOutputCapability == nullptr || ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedCameraOutputCapability failed."); return; } if (cameraOutputCapability->previewProfiles == nullptr) { OH_LOG_ERROR(LOG_APP, "previewProfiles == null"); return; } // Select an appropriate preview resolution from previewProfiles of cameraOutputCapability. previewProfile = cameraOutputCapability->previewProfiles[0]; if (cameraOutputCapability->photoProfiles == nullptr) { OH_LOG_ERROR(LOG_APP, "photoProfiles == null"); return; } // Select an appropriate photo resolution from photoProfiles of cameraOutputCapability. photoProfile = cameraOutputCapability->photoProfiles[0]; // Create a preview output stream, with the previewSurfaceId parameter set to the ID of the surface provided by the XComponent. ret = OH_CameraManager_CreatePreviewOutput(cameraManager, previewProfile, previewSurfaceId, &previewOutput); if (previewProfile == nullptr || previewOutput == nullptr || ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreatePreviewOutput failed."); return; } // Listen for preview output errors. ret = OH_PreviewOutput_RegisterCallback(previewOutput, GetPreviewOutputListener()); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_PreviewOutput_RegisterCallback failed."); } // Create a photo output stream. ret = OH_CameraManager_CreatePhotoOutputWithoutSurface(cameraManager, photoProfile, &photoOutput); // Listen for the one-time photo capture callback. ret = OH_PhotoOutput_RegisterPhotoAvailableCallback(photoOutput, OnPhotoAvailable); // Create a session. ret = OH_CameraManager_CreateCaptureSession(cameraManager, &captureSession); if (captureSession == nullptr || ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateCaptureSession failed."); return; } // Listen for session errors. ret = OH_CaptureSession_RegisterCallback(captureSession, GetCaptureSessionRegister()); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_RegisterCallback failed."); } // Start configuration for the session. ret = OH_CaptureSession_BeginConfig(captureSession); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_BeginConfig failed."); return; } // Add the camera input stream to the session. ret = OH_CaptureSession_AddInput(captureSession, cameraInput); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddInput failed."); return; } // Add the preview output stream to the session. ret = OH_CaptureSession_AddPreviewOutput(captureSession, previewOutput); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddPreviewOutput failed."); return; } // Add the photo output stream to the session. ret = OH_CaptureSession_AddPhotoOutput(captureSession, photoOutput); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddPhotoOutput failed."); return; } // Commit the session configuration. ret = OH_CaptureSession_CommitConfig(captureSession); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_CommitConfig failed."); return; } // Start the session. ret = OH_CaptureSession_Start(captureSession); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Start failed."); return; } // Check whether the camera has flash. Camera_FlashMode flashMode = FLASH_MODE_AUTO; bool hasFlash = false; ret = OH_CaptureSession_HasFlash(captureSession, &hasFlash); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_HasFlash failed."); } if (hasFlash) { OH_LOG_INFO(LOG_APP, "hasFlash success"); } else { OH_LOG_ERROR(LOG_APP, "hasFlash fail"); } // Check whether a flash mode is supported. bool isSupported = false; ret = OH_CaptureSession_IsFlashModeSupported(captureSession, flashMode, &isSupported); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_IsFlashModeSupported failed."); } if (isSupported) { OH_LOG_INFO(LOG_APP, "isFlashModeSupported success"); // Set the flash mode. ret = OH_CaptureSession_SetFlashMode(captureSession, flashMode); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_CaptureSession_SetFlashMode success."); } else { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_SetFlashMode failed. ret : %{public}d ", ret); } // Obtain the flash mode in use. ret = OH_CaptureSession_GetFlashMode(captureSession, &flashMode); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_CaptureSession_GetFlashMode success. flashMode: %{public}d ", flashMode); } else { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_GetFlashMode failed. ret : %{public}d ", ret); } } else { OH_LOG_ERROR(LOG_APP, "isFlashModeSupported fail"); } // Check whether the continuous auto focus is supported. Camera_FocusMode focusMode = FOCUS_MODE_CONTINUOUS_AUTO; bool isFocusModeSupported = false; ret = OH_CaptureSession_IsFocusModeSupported(captureSession, focusMode, &isFocusModeSupported); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_IsFocusModeSupported failed."); } if (isFocusModeSupported) { OH_LOG_INFO(LOG_APP, "isFocusModeSupported success"); ret = OH_CaptureSession_SetFocusMode(captureSession, focusMode); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_SetFocusMode failed. ret : %{public}d ", ret); } ret = OH_CaptureSession_GetFocusMode(captureSession, &focusMode); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_CaptureSession_GetFocusMode success. focusMode%{public}d ", focusMode); } else { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_GetFocusMode failed. ret : %{public}d ", ret); } } else { OH_LOG_ERROR(LOG_APP, "isFocusModeSupported fail"); } // Obtain the zoom ratio range supported by the camera. float minZoom; float maxZoom; ret = OH_CaptureSession_GetZoomRatioRange(captureSession, &minZoom, &maxZoom); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_GetZoomRatioRange failed."); } else { OH_LOG_INFO(LOG_APP, "OH_CaptureSession_GetZoomRatioRange success. minZoom: %{public}f, maxZoom:%{public}f", minZoom, maxZoom); } // Set a zoom ratio. ret = OH_CaptureSession_SetZoomRatio(captureSession, maxZoom); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_CaptureSession_SetZoomRatio success."); } else { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_SetZoomRatio failed. ret : %{public}d ", ret); } // Obtain the zoom ratio of the camera. ret = OH_CaptureSession_GetZoomRatio(captureSession, &maxZoom); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_CaptureSession_GetZoomRatio success. zoom: %{public}f ", maxZoom); } else { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_GetZoomRatio failed. ret : %{public}d ", ret); } // Take photos without photo capture settings. ret = OH_PhotoOutput_Capture(photoOutput); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_PhotoOutput_Capture success "); } else { OH_LOG_ERROR(LOG_APP, "OH_PhotoOutput_Capture failed. ret : %{public}d ", ret); } // Stop the session. ret = OH_CaptureSession_Stop(captureSession); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_CaptureSession_Stop success "); } else { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Stop failed. ret : %{public}d ", ret); } // Release the camera input stream. ret = OH_CameraInput_Close(cameraInput); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_CameraInput_Close success "); } else { OH_LOG_ERROR(LOG_APP, "OH_CameraInput_Close failed. ret : %{public}d ", ret); } // Release the preview output stream. ret = OH_PreviewOutput_Release(previewOutput); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_PreviewOutput_Release success "); } else { OH_LOG_ERROR(LOG_APP, "OH_PreviewOutput_Release failed. ret : %{public}d ", ret); } // Release the photo output stream. ret = OH_PhotoOutput_Release(photoOutput); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_PhotoOutput_Release success "); } else { OH_LOG_ERROR(LOG_APP, "OH_PhotoOutput_Release failed. ret : %{public}d ", ret); } // Release the session. ret = OH_CaptureSession_Release(captureSession); if (ret == CAMERA_OK) { OH_LOG_INFO(LOG_APP, "OH_CaptureSession_Release success "); } else { OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Release failed. ret : %{public}d ", ret); } // Release the resources. ret = OH_CameraManager_DeleteSupportedCameras(cameraManager, cameras, size); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "Delete Cameras failed."); } else { OH_LOG_ERROR(LOG_APP, "OH_CameraManager_DeleteSupportedCameras. ok"); } ret = OH_CameraManager_DeleteSupportedCameraOutputCapability(cameraManager, cameraOutputCapability); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "Delete Cameras failed."); } else { OH_LOG_ERROR(LOG_APP, "OH_CameraManager_DeleteSupportedCameraOutputCapability. ok"); } ret = OH_Camera_DeleteCameraManager(cameraManager); if (ret != CAMERA_OK) { OH_LOG_ERROR(LOG_APP, "Delete Cameras failed."); } else { OH_LOG_ERROR(LOG_APP, "OH_Camera_DeleteCameraManager. ok"); } }