diff options
| -rw-r--r-- | Documentation/guides/pipeline-handler.rst | 67 |
1 files changed, 34 insertions, 33 deletions
diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst index 5c5cf5a9..54c8e7f1 100644 --- a/Documentation/guides/pipeline-handler.rst +++ b/Documentation/guides/pipeline-handler.rst @@ -106,7 +106,7 @@ functionalities descibed above. Below is a brief overview of each of those: Abstracts camera sensor handling by hiding the details of the V4L2 subdevice kernel API and caching sensor information. -- `CameraData <http://libcamera.org/api-html/classlibcamera_1_1CameraData.html>`_: +- `Camera::Private <http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html>`_: Represents device-specific data a pipeline handler associates to each Camera instance. @@ -416,26 +416,26 @@ receivers port output. The Pipeline Handler is responsible for defining the set of Streams associated with the Camera. -Each Camera has instance-specific data represented using the `CameraData`_ +Each Camera has instance-specific data represented using the `Camera::Private`_ class, which can be extended for the specific needs of the pipeline handler. -.. _CameraData: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html +.. _Camera::Private: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html -To support the Camera we will later register, we need to create a CameraData +To support the Camera we will later register, we need to create a Camera::Private class that we can implement for our specific Pipeline Handler. -Define a new ``VividCameraData()`` class derived from ``CameraData`` by adding -the following code before the PipelineHandlerVivid class definition where it -will be used: +Define a new ``VividCameraPrivate()`` class derived from ``Camera::Private`` by +adding the following code before the PipelineHandlerVivid class definition where +it will be used: .. code-block:: cpp - class VividCameraData : public CameraData + class VividCameraData : public Camera::Private { public: VividCameraData(PipelineHandler *pipe, MediaDevice *media) - : CameraData(pipe), media_(media), video_(nullptr) + : Camera::Private(pipe), media_(media), video_(nullptr) { } @@ -457,17 +457,17 @@ single stream, represented by the ``VividCameraData`` class members. More complex pipeline handlers might register cameras composed of several video devices and sub-devices, or multiple streams per camera that represent the several components of the image capture pipeline. You should represent all these -components in the ``CameraData`` derived class when developing a custom +components in the ``Camera::Private`` derived class when developing a custom PipelineHandler. In our example VividCameraData we implement an ``init()`` function to prepare -the object from our PipelineHandler, however the CameraData class does not +the object from our PipelineHandler, however the Camera::Private class does not specify the interface for initialisation and PipelineHandlers can manage this -based on their own needs. Derived CameraData classes are used only by their +based on their own needs. Derived Camera::Private classes are used only by their respective pipeline handlers. -The CameraData class stores the context required for each camera instance and -is usually responsible for opening all Devices used in the capture pipeline. +The Camera::Private class stores the context required for each camera instance +and is usually responsible for opening all Devices used in the capture pipeline. We can now implement the ``init`` function for our example Pipeline Handler to create a new V4L2 video device from the media entity, which we can specify using @@ -488,11 +488,11 @@ single capture device named 'vivid-000-vid-cap' by the device. return 0; } -The CameraData should be created and initialised before we move on to register a -new Camera device so we need to construct and initialise our +The VividCameraData should be created and initialised before we move on to +register a new Camera device so we need to construct and initialise our VividCameraData after we have identified our device within PipelineHandlerVivid::match(). The VividCameraData is wrapped by a -std::unique_ptr to help manage the lifetime of our CameraData instance. +std::unique_ptr to help manage the lifetime of the instance. If the camera data initialization fails, return ``false`` to indicate the failure to the ``match()`` function and prevent retrying of the pipeline @@ -509,9 +509,9 @@ handler. Once the camera data has been initialized, the Camera device instances and the associated streams have to be registered. Create a set of streams for the camera, which for this device is only one. You create a camera using the static -`Camera::create`_ function, passing the pipeline handler, the id of the camera, -and the streams available. Then register the camera and its data with the -pipeline handler and camera manager using `registerCamera`_. +`Camera::create`_ function, passing the Camera::Private instance, the id of the +camera, and the streams available. Then register the camera with the pipeline +handler and camera manager using `registerCamera`_. Finally with a successful construction, we return 'true' indicating that the PipelineHandler successfully matched and constructed a device. @@ -549,23 +549,24 @@ Our match function should now look like the following: /* Create and register the camera. */ std::set<Stream *> streams{ &data->stream_ }; - std::shared_ptr<Camera> camera = Camera::create(this, data->video_->deviceName(), streams); - registerCamera(std::move(camera), std::move(data)); + const std::string &id = data->video_->deviceName(); + std::shared_ptr<Camera> camera = Camera::create(data.release(), id, streams); + registerCamera(std::move(camera)); return true; } -We will need to use our custom CameraData class frequently throughout the +We will need to use our custom VividCameraData class frequently throughout the pipeline handler, so we add a private convenience helper to our Pipeline handler -to obtain and cast the custom CameraData instance from a Camera instance. +to obtain and cast the custom VividCameraData instance from a Camera::Private +instance. .. code-block:: cpp private: - VividCameraData *cameraData(const Camera *camera) + VividCameraData *cameraData(Camera *camera) { - return static_cast<VividCameraData *>( - PipelineHandler::cameraData(camera)); + return static_cast<VividCameraData *>(camera->_d()); } At this point, you need to add the following new includes to provide the Camera @@ -595,12 +596,12 @@ are defined by src/libcamera/`properties_ids.yaml`_. Pipeline handlers can optionally register the list of controls an application can set as well as a list of immutable camera properties. Being both -Camera-specific values, they are represented in the ``CameraData`` base class, -which provides two members for this purpose: the `CameraData::controlInfo_`_ and -the `CameraData::properties_`_ fields. +Camera-specific values, they are represented in the ``Camera::Private`` base +class, which provides two members for this purpose: the +`Camera::Private::controlInfo_`_ and the `Camera::Private::properties_`_ fields. -.. _CameraData::controlInfo_: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html#ab9fecd05c655df6084a2233872144a52 -.. _CameraData::properties_: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html#a84002c29f45bd35566c172bb65e7ec0b +.. _Camera::Private::controlInfo_: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html#ab4e183eb4dabe929d1b2bbbb519b969f +.. _Camera::Private::properties_: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html#ad31f12f5ed9c1fbe25750902f4791064 The ``controlInfo_`` field represents a map of ``ControlId`` instances associated with the limits of valid values supported for the control. More @@ -618,7 +619,7 @@ Complete the initialization of the ``VividCameraData`` class by adding the following code to the ``VividCameraData::init()`` function to initialise the controls. For more complex control configurations, this could of course be broken out to a separate function, but for now we just initialise the small set -inline in our CameraData init: +inline in our VividCameraData init: .. code-block:: cpp |