[libcamera-devel] [PATCH v4 1/7] libcamera: v4l2_subdevice: Expose setSelection()

[Laurent Pinchart]

Hi Jacopo,

Thank you for the patch.

On Mon, Apr 27, 2020 at 11:32:30PM +0200, Jacopo Mondi wrote:
> Expose V4L2Subdevice::setSelection() method and drop
> V4L2Subdevice::setCrop() and V4L2Subdevice::setComopse() as wrapping
> each target with a single function does not provide any benefit.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
>  src/libcamera/include/v4l2_subdevice.h |  7 +--
>  src/libcamera/pipeline/ipu3/ipu3.cpp   |  4 +-
>  src/libcamera/v4l2_subdevice.cpp       | 76 ++++++++++----------------
>  3 files changed, 34 insertions(+), 53 deletions(-)
> 
> diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
> index 4a04eadfb1f9..9a5c812db9b6 100644
> --- a/src/libcamera/include/v4l2_subdevice.h
> +++ b/src/libcamera/include/v4l2_subdevice.h
> @@ -46,8 +46,8 @@ public:
>  
>  	const MediaEntity *entity() const { return entity_; }
>  
> -	int setCrop(unsigned int pad, Rectangle *rect);
> -	int setCompose(unsigned int pad, Rectangle *rect);
> +	int setSelection(unsigned int pad, unsigned int target,
> +			 Rectangle *rect);

A note on API design, not intended to be applied to this patch: with two
integer parameters for pad and target, there's a risk that the caller
would use them in the wrong order. If we defined

	enum V4L2SelectionTarget {
		V4L2SelectionTargetCrop = V4L2_SEL_TGT_CROP,
		...
	};

and turned the function into

	int setSelection(unsigned int pad, V4L2SelectionTarget target,
			 Rectangle *rect);

then the compiler would tell us if we called

	subdev->setSelection(V4L2SelectionTargetCrop, 0, &rect);

>  
>  	ImageFormats formats(unsigned int pad);
>  
> @@ -67,9 +67,6 @@ private:
>  	std::vector<SizeRange> enumPadSizes(unsigned int pad,
>  					    unsigned int code);
>  
> -	int setSelection(unsigned int pad, unsigned int target,
> -			 Rectangle *rect);
> -
>  	const MediaEntity *entity_;
>  };
>  
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index b45900159d06..ff33f15f9eac 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -1135,11 +1135,11 @@ int ImgUDevice::configureInput(const Size &size,
>  		.width = inputFormat->size.width,
>  		.height = inputFormat->size.height,
>  	};
> -	ret = imgu_->setCrop(PAD_INPUT, &rect);
> +	ret = imgu_->setSelection(PAD_INPUT, V4L2_SEL_TGT_CROP, &rect);
>  	if (ret)
>  		return ret;
>  
> -	ret = imgu_->setCompose(PAD_INPUT, &rect);
> +	ret = imgu_->setSelection(PAD_INPUT, V4L2_SEL_TGT_COMPOSE, &rect);
>  	if (ret)
>  		return ret;
>  
> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
> index 5a479a96b795..432e89eacbd3 100644
> --- a/src/libcamera/v4l2_subdevice.cpp
> +++ b/src/libcamera/v4l2_subdevice.cpp
> @@ -134,27 +134,42 @@ int V4L2Subdevice::open()
>   */
>  
>  /**
> - * \brief Set a crop rectangle on one of the V4L2 subdevice pads
> + * \brief Set selection rectangle \a rect for \a target
>   * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
> - * \param[inout] rect The rectangle describing crop target area
> + * \param[in] target The selection target defined by the V4L2_SEL_TGT_* flags
> + * \param[inout] rect The selection rectangle to be applied

Maybe you could add

  * \todo Define a V4L2SelectionTarget enum for the selection target

here to remember the comment above.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

(and no need to submit a new version just for this, you can fix when
pushing if you agree with the comment.

>   * \return 0 on success or a negative error code otherwise
>   */
> -int V4L2Subdevice::setCrop(unsigned int pad, Rectangle *rect)
> +int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
> +				Rectangle *rect)
>  {
> -	return setSelection(pad, V4L2_SEL_TGT_CROP, rect);
> -}
> +	struct v4l2_subdev_selection sel = {};
>  
> -/**
> - * \brief Set a compose rectangle on one of the V4L2 subdevice pads
> - * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
> - * \param[inout] rect The rectangle describing the compose target area
> - * \return 0 on success or a negative error code otherwise
> - */
> -int V4L2Subdevice::setCompose(unsigned int pad, Rectangle *rect)
> -{
> -	return setSelection(pad, V4L2_SEL_TGT_COMPOSE, rect);
> -}
> +	sel.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> +	sel.pad = pad;
> +	sel.target = target;
> +	sel.flags = 0;
>  
> +	sel.r.left = rect->x;
> +	sel.r.top = rect->y;
> +	sel.r.width = rect->width;
> +	sel.r.height = rect->height;
> +
> +	int ret = ioctl(VIDIOC_SUBDEV_S_SELECTION, &sel);
> +	if (ret < 0) {
> +		LOG(V4L2, Error)
> +			<< "Unable to set rectangle " << target << " on pad "
> +			<< pad << ": " << strerror(-ret);
> +		return ret;
> +	}
> +
> +	rect->x = sel.r.left;
> +	rect->y = sel.r.top;
> +	rect->width = sel.r.width;
> +	rect->height = sel.r.height;
> +
> +	return 0;
> +}
>  /**
>   * \brief Enumerate all media bus codes and frame sizes on a \a pad
>   * \param[in] pad The 0-indexed pad number to enumerate formats on
> @@ -343,35 +358,4 @@ std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
>  	return sizes;
>  }
>  
> -int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
> -				Rectangle *rect)
> -{
> -	struct v4l2_subdev_selection sel = {};
> -
> -	sel.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> -	sel.pad = pad;
> -	sel.target = target;
> -	sel.flags = 0;
> -
> -	sel.r.left = rect->x;
> -	sel.r.top = rect->y;
> -	sel.r.width = rect->width;
> -	sel.r.height = rect->height;
> -
> -	int ret = ioctl(VIDIOC_SUBDEV_S_SELECTION, &sel);
> -	if (ret < 0) {
> -		LOG(V4L2, Error)
> -			<< "Unable to set rectangle " << target << " on pad "
> -			<< pad << ": " << strerror(-ret);
> -		return ret;
> -	}
> -
> -	rect->x = sel.r.left;
> -	rect->y = sel.r.top;
> -	rect->width = sel.r.width;
> -	rect->height = sel.r.height;
> -
> -	return 0;
> -}
> -
>  } /* namespace libcamera */

-- 
Regards,

Laurent Pinchart