[libcamera-devel] [PATCH v3 07/10] libcamera: transform: Add operations with Orientation

[David Plowman]

Hi Jacopo

Thanks for these new versions. I do like them!!

On Tue, 18 Jul 2023 at 11:52, Jacopo Mondi
<jacopo.mondi at ideasonboard.com> wrote:
>
> Add two operations that allows to combine Transform with Orientation.
>
> - Transform operator/(Orientation1, Orientation2)
>   allows to easily get back the Transform that needs to be applied to
>   Orientation2 to get Orientation1
>
> - Orientation operator*(Orientation1, Transform)
>   allows to apply a Transform to an Orientation and obtain the
>   combination of the two
>
> These two operations allow applications to use Transforms to
> manipulate the Orientation inside the CameraConfiguration, if they
> wish.
>
> Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>

Reviewed-by: David Plowman <david.plowman at raspberrypi.com>

Thanks
David

> ---
>  include/libcamera/transform.h |  3 +++
>  src/libcamera/transform.cpp   | 37 +++++++++++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+)
>
> diff --git a/include/libcamera/transform.h b/include/libcamera/transform.h
> index 14f1db0e8572..847a1f94713c 100644
> --- a/include/libcamera/transform.h
> +++ b/include/libcamera/transform.h
> @@ -74,6 +74,9 @@ Transform transformFromRotation(int angle, bool *success = nullptr);
>  Transform transformFromOrientation(const Orientation &orientation);
>  Orientation transformToOrientation(const Transform &transform);
>
> +Transform operator/(const Orientation &o1, const Orientation &o2);
> +Orientation operator*(const Orientation &o1, const Transform &t);
> +
>  const char *transformToString(Transform t);
>
>  } /* namespace libcamera */
> diff --git a/src/libcamera/transform.cpp b/src/libcamera/transform.cpp
> index d192d63d9290..80cd804ca530 100644
> --- a/src/libcamera/transform.cpp
> +++ b/src/libcamera/transform.cpp
> @@ -362,6 +362,43 @@ Orientation transformToOrientation(const Transform &transform)
>         return Orientation::rotate0;
>  }
>
> +/**
> + * \brief Return the Transform that applied to \a o2 gives \a o1
> + * \param o1 The Orientation to obtain
> + * \param o2 The base Orientation
> + *
> + * This operation can be used to easily compute the Transform to apply to a
> + * base orientation \a o2 to get the desired orientation \a o1.
> + *
> + * The CameraSensor class uses this function to compute what Transform to apply
> + * to a camera with mounting rotation \a o2 (the base) to obtain the user
> + * requested orientation \a o1.
> + *
> + * \return A Transform that applied to \a o2 gives \a o1
> + */
> +Transform operator/(const Orientation &o1, const Orientation &o2)
> +{
> +       Transform t1 = transformFromOrientation(o1);
> +       Transform t2 = transformFromOrientation(o2);
> +
> +       return -t2 * t1;
> +}
> +
> +/**
> + * \brief Apply the Transform \a t on the base orientation \a o
> + * \param o The base orientation
> + * \param t The transform to apply on \a o
> + * \return The Orientation resulting from applying \a t on \a o
> + */
> +Orientation operator*(const Orientation &o, const Transform &t)
> +{
> +       /*
> +        * Apply a Transform corresponding to the base orientation first and
> +        * then apply \a t to it.
> +        */
> +       return transformToOrientation(transformFromOrientation(o) * t);
> +}
> +
>  /**
>   * \brief Return a character string describing the transform
>   * \param[in] t The transform to be described.
> --
> 2.40.1
>