[libcamera-devel] [PATCH v3 3/8] ipa: Add base class defining AF algorithm interface

[Jacopo Mondi]

Hi Daniel

On Thu, Jan 19, 2023 at 09:41:07AM +0100, Daniel Semkowicz via libcamera-devel wrote:
> Define common interface with basic functions that should be supported
> by Auto Focus algorithms.
>

As commented in the previous version, I like this approach very much

> Signed-off-by: Daniel Semkowicz <dse at thaumatec.com>
> ---
>  src/ipa/libipa/algorithms/af_interface.cpp | 92 ++++++++++++++++++++++
>  src/ipa/libipa/algorithms/af_interface.h   | 41 ++++++++++
>  src/ipa/libipa/algorithms/meson.build      |  9 +++
>  src/ipa/libipa/meson.build                 |  6 ++
>  4 files changed, 148 insertions(+)
>  create mode 100644 src/ipa/libipa/algorithms/af_interface.cpp
>  create mode 100644 src/ipa/libipa/algorithms/af_interface.h
>  create mode 100644 src/ipa/libipa/algorithms/meson.build
>
> diff --git a/src/ipa/libipa/algorithms/af_interface.cpp b/src/ipa/libipa/algorithms/af_interface.cpp
> new file mode 100644
> index 00000000..af341d13
> --- /dev/null
> +++ b/src/ipa/libipa/algorithms/af_interface.cpp

Nit: af_interface.[cpp|h] or just af.[cpp|h] ?

> @@ -0,0 +1,92 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2022, Theobroma Systems
> + *
> + * af_interface.cpp - Autofocus control algorithm interface
> + */
> +
> +#include "af_interface.h"
> +
> +/**
> + * \file af_interface.h
> + * \brief AF algorithm common interface
> + */
> +
> +namespace libcamera::ipa::common::algorithms {
> +
> +/**
> + * \class AfInterface
> + * \brief Common interface for auto-focus algorithms
> + * \tparam Module The IPA module type for this class of algorithms

You don't have the Module template argument anymore

> + *
> + * The AfInterface class defines a standard interface for IPA auto focus
> + * algorithms.
> + */
> +
> +/**
> + * \fn AfInterface::setMode()
> + * \brief Set auto focus mode
> + * \param[in] mode AF mode

I was about to suggest \sa controls::AfModeEnum but doxygen already
links the parameter type to the right documentation page, so it's not
necessary.

However, as this interface implements the Af controls defined in
control_ids.yaml I would be tempted to say that we might even /copydoc
so that the documentation is centralized in a single place ??


> + */
> +
> +/**
> + * \fn AfInterface::setRange()
> + * \brief set the range of focus distances that is scanned
> + * \param[in] range AF range
> + */
> +
> +/**
> + * \fn AfInterface::setSpeed()
> + * \brief Set how fast algorithm should move the lens
> + * \param[in] speed Lens move speed
> + */
> +
> +/**
> + * \fn AfInterface::setMeteringMode()
> + * \brief Set AF metering mode
> + * \param[in] metering AF metering mode
> + */
> +
> +/**
> + * \fn AfInterface::setWindows()
> + * \brief Set AF windows
> + * \param[in] windows AF windows
> + *
> + * Sets the focus windows used by the AF algorithm when AfMetering is set
> + * to AfMeteringWindows.
> + */
> +
> +/**
> + * \fn AfInterface::setTrigger()
> + * \brief Starts or cancels the autofocus scan
> + * \param[in] trigger Trigger mode
> + */
> +
> +/**
> + * \fn AfInterface::setPause()
> + * \brief Pause the autofocus while in AfModeContinuous mode.
> + * \param[in] pause Pause mode
> + */
> +
> +/**
> + * \fn AfInterface::setLensPosition()
> + * \brief Set the lens position while in AfModeManual
> + * \param[in] lensPosition Lens position
> + */
> +
> +/**
> + * \fn AfInterface::getState()

Minor nit: for getters we don't usually prepend "get", so this could
just be AfInterface::state() ?

> + * \brief Get the current state of the AF algorithm
> + * \return AF state
> + */
> +
> +/**
> + * \fn AfInterface::getPauseState()
> + * \brief Get the current pause state of the AF algorithm.
> + * \return AF pause state
> + *
> + * Only applicable in continuous (AfModeContinuous) mode. In other modes,
> + * AfPauseStateRunning is always returned.

See, in this case the documentation of controls::AfPauseState has gone
through a lot of discussions, and trying to resume it here might not
be ideal. Plus it has to be kept in sync with the control
documentation.

I tried

        \copydoc libcamera::controls::AfPauseState

but it doesn't work here..


> + */
> +
> +} /* namespace libcamera::ipa::common::algorithms */
> diff --git a/src/ipa/libipa/algorithms/af_interface.h b/src/ipa/libipa/algorithms/af_interface.h
> new file mode 100644
> index 00000000..b6b7bea6
> --- /dev/null
> +++ b/src/ipa/libipa/algorithms/af_interface.h
> @@ -0,0 +1,41 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2022, Theobroma Systems
> + *
> + * af_interface.h - Autofocus control algorithm interface
> + */
> +#pragma once
> +
> +#include <libcamera/control_ids.h>
> +
> +namespace libcamera::ipa::common::algorithms {
> +
> +class AfInterface
> +{
> +public:
> +	AfInterface() = default;

Do you even need a constructor ?

> +
> +	virtual ~AfInterface() {}
> +
> +	virtual void setMode(controls::AfModeEnum mode) = 0;
> +
> +	virtual void setRange(controls::AfRangeEnum range) = 0;
> +
> +	virtual void setSpeed(controls::AfSpeedEnum speed) = 0;
> +
> +	virtual void setMeteringMode(controls::AfMeteringEnum metering) = 0;
> +
> +	virtual void setWindows(Span<const Rectangle> windows) = 0;
> +
> +	virtual void setTrigger(controls::AfTriggerEnum trigger) = 0;
> +
> +	virtual void setPause(controls::AfPauseEnum pause) = 0;
> +
> +	virtual void setLensPosition(float lensPosition) = 0;
> +
> +	virtual controls::AfStateEnum getState() = 0;
> +
> +	virtual controls::AfPauseStateEnum getPauseState() = 0;
> +};
> +
> +} /* namespace libcamera::ipa::common::algorithms */
> diff --git a/src/ipa/libipa/algorithms/meson.build b/src/ipa/libipa/algorithms/meson.build
> new file mode 100644
> index 00000000..0a1f18fa
> --- /dev/null
> +++ b/src/ipa/libipa/algorithms/meson.build
> @@ -0,0 +1,9 @@
> +# SPDX-License-Identifier: CC0-1.0
> +
> +common_ipa_algorithms_headers = files([
> +    'af_interface.h',
> +])
> +
> +common_ipa_algorithms_sources = files([
> +    'af_interface.cpp',
> +])
> diff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build
> index 016b8e0e..0cfc551a 100644
> --- a/src/ipa/libipa/meson.build
> +++ b/src/ipa/libipa/meson.build
> @@ -1,5 +1,7 @@
>  # SPDX-License-Identifier: CC0-1.0
>
> +subdir('algorithms')
> +
>  libipa_headers = files([
>      'algorithm.h',
>      'camera_sensor_helper.h',
> @@ -8,6 +10,8 @@ libipa_headers = files([
>      'module.h',
>  ])
>
> +libipa_headers += common_ipa_algorithms_headers
> +
>  libipa_sources = files([
>      'algorithm.cpp',
>      'camera_sensor_helper.cpp',
> @@ -16,6 +20,8 @@ libipa_sources = files([
>      'module.cpp',
>  ])
>
> +libipa_sources += common_ipa_algorithms_sources
> +
>  libipa_includes = include_directories('..')
>
>  libipa = static_library('ipa', [libipa_sources, libipa_headers],

Minors on the doc apart, it seems all good to me.

Let me copy RPi folks in, as they just upstreamed a PDAF based
auto-focus algorithm to check with them if there's a chance their
implementation can inherit from this class.

Thanks again!
    j
> --
> 2.39.0
>