[PATCH v3 03/16] libcamera: matrix: Add a Span based constructor

[Paul Elder]

On Thu, Apr 03, 2025 at 05:49:08PM +0200, Stefan Klug wrote:
> When one wants to create a Matrix from existing data, currently the only
> way is via std::array. Add a Span based constructor to allow creation
> from vectors and alike.
> 
> Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>

> 
> ---
> 
> Changes in v2:
> - Added this patch
> 
> Changes in v3:
> - Pass the Span by value
> ---
>  include/libcamera/internal/matrix.h |  5 +++++
>  src/libcamera/matrix.cpp            | 10 ++++++++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/include/libcamera/internal/matrix.h b/include/libcamera/internal/matrix.h
> index 512c1162c3bc..6d40567af0a0 100644
> --- a/include/libcamera/internal/matrix.h
> +++ b/include/libcamera/internal/matrix.h
> @@ -34,6 +34,11 @@ public:
>  		std::copy(data.begin(), data.end(), data_.begin());
>  	}
>  
> +	Matrix(const Span<const T, Rows * Cols> data)
> +	{
> +		std::copy(data.begin(), data.end(), data_.begin());
> +	}
> +
>  	static constexpr Matrix identity()
>  	{
>  		Matrix ret;
> diff --git a/src/libcamera/matrix.cpp b/src/libcamera/matrix.cpp
> index e7e027225666..49e2aa3b4f2c 100644
> --- a/src/libcamera/matrix.cpp
> +++ b/src/libcamera/matrix.cpp
> @@ -41,6 +41,16 @@ LOG_DEFINE_CATEGORY(Matrix)
>   * number of rows and columns of the matrix (Rows x Cols).
>   */
>  
> +/**
> + * \fn Matrix::Matrix(const Span<const T, Rows * Cols> data)
> + * \brief Construct a matrix from supplied data
> + * \param[in] data Data from which to construct a matrix
> + *
> + * \a data is a one-dimensional Span and will be turned into a matrix in
> + * row-major order. The size of \a data must be equal to the product of the
> + * number of rows and columns of the matrix (Rows x Cols).
> + */
> +
>  /**
>   * \fn Matrix::identity()
>   * \brief Construct an identity matrix
> -- 
> 2.43.0
>