[PATCH v4 07/20] libcamera: converter_v4l2_m2m: Refactor get crop bounds code

[Paul Elder]

On Mon, Dec 16, 2024 at 04:40:47PM +0100, Stefan Klug wrote:
> In an upcoming patch it is necessary to get the crop bounds on the
> converter itself. The V4L2M2MConverter contains code that is very
> similar to the get crop bounds code in the V4L2M2MStream. Merge these
> code blocks into a static function to be used from both classes.  This
> patch contains no functional changes.
> 
> Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>

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

> 
> ---
> 
> Changes in v4:
> - Split patch from libcamera: converter_v4l2_m2m: Improve crop bounds
>   support
> ---
>  .../converter/converter_v4l2_m2m.cpp          | 106 +++++++++---------
>  1 file changed, 52 insertions(+), 54 deletions(-)
> 
> diff --git a/src/libcamera/converter/converter_v4l2_m2m.cpp b/src/libcamera/converter/converter_v4l2_m2m.cpp
> index d63ef2f8028f..8c341fe199f6 100644
> --- a/src/libcamera/converter/converter_v4l2_m2m.cpp
> +++ b/src/libcamera/converter/converter_v4l2_m2m.cpp
> @@ -30,6 +30,52 @@ namespace libcamera {
>  
>  LOG_DECLARE_CATEGORY(Converter)
>  
> +namespace {
> +
> +int getCropBounds(V4L2VideoDevice *device, Rectangle &minCrop,
> +		  Rectangle &maxCrop)
> +{
> +	Rectangle minC;
> +	Rectangle maxC;
> +
> +	/* Find crop bounds */
> +	minC.width = 1;
> +	minC.height = 1;
> +	maxC.width = UINT_MAX;
> +	maxC.height = UINT_MAX;
> +
> +	int ret = device->setSelection(V4L2_SEL_TGT_CROP, &minC);
> +	if (ret) {
> +		LOG(Converter, Error)
> +			<< "Could not query minimum selection crop: "
> +			<< strerror(-ret);
> +		return ret;
> +	}
> +
> +	ret = device->getSelection(V4L2_SEL_TGT_CROP_BOUNDS, &maxC);
> +	if (ret) {
> +		LOG(Converter, Error)
> +			<< "Could not query maximum selection crop: "
> +			<< strerror(-ret);
> +		return ret;
> +	}
> +
> +	/* Reset the crop to its maximum */
> +	ret = device->setSelection(V4L2_SEL_TGT_CROP, &maxC);
> +	if (ret) {
> +		LOG(Converter, Error)
> +			<< "Could not reset selection crop: "
> +			<< strerror(-ret);
> +		return ret;
> +	}
> +
> +	minCrop = minC;
> +	maxCrop = maxC;
> +	return 0;
> +}
> +
> +} /* namespace */
> +
>  /* -----------------------------------------------------------------------------
>   * V4L2M2MConverter::V4L2M2MStream
>   */
> @@ -98,41 +144,10 @@ int V4L2M2MConverter::V4L2M2MStream::configure(const StreamConfiguration &inputC
>  	outputBufferCount_ = outputCfg.bufferCount;
>  
>  	if (converter_->features() & Feature::InputCrop) {
> -		Rectangle minCrop;
> -		Rectangle maxCrop;
> -
> -		/* Find crop bounds */
> -		minCrop.width = 1;
> -		minCrop.height = 1;
> -		maxCrop.width = UINT_MAX;
> -		maxCrop.height = UINT_MAX;
> -
> -		ret = setInputSelection(V4L2_SEL_TGT_CROP, &minCrop);
> -		if (ret) {
> -			LOG(Converter, Error)
> -				<< "Could not query minimum selection crop: "
> -				<< strerror(-ret);
> -			return ret;
> -		}
> -
> -		ret = getInputSelection(V4L2_SEL_TGT_CROP_BOUNDS, &maxCrop);
> -		if (ret) {
> -			LOG(Converter, Error)
> -				<< "Could not query maximum selection crop: "
> -				<< strerror(-ret);
> +		ret = getCropBounds(m2m_->output(), inputCropBounds_.first,
> +				    inputCropBounds_.second);
> +		if (ret)
>  			return ret;
> -		}
> -
> -		/* Reset the crop to its maximum */
> -		ret = setInputSelection(V4L2_SEL_TGT_CROP, &maxCrop);
> -		if (ret) {
> -			LOG(Converter, Error)
> -				<< "Could not reset selection crop: "
> -				<< strerror(-ret);
> -			return ret;
> -		}
> -
> -		inputCropBounds_ = { minCrop, maxCrop };
>  	}
>  
>  	return 0;
> @@ -258,27 +273,10 @@ V4L2M2MConverter::V4L2M2MConverter(MediaDevice *media)
>  		return;
>  	}
>  
> -	/* Discover Feature::InputCrop */
> +	Rectangle minCrop;
>  	Rectangle maxCrop;
> -	maxCrop.width = UINT_MAX;
> -	maxCrop.height = UINT_MAX;
> -
> -	ret = m2m_->output()->setSelection(V4L2_SEL_TGT_CROP, &maxCrop);
> -	if (ret)
> -		return;
> -
> -	/*
> -	 * Rectangles for cropping targets are defined even if the device
> -	 * does not support cropping. Their sizes and positions will be
> -	 * fixed in such cases.
> -	 *
> -	 * Set and inspect a crop equivalent to half of the maximum crop
> -	 * returned earlier. Use this to determine whether the crop on
> -	 * input is really supported.
> -	 */
> -	Rectangle halfCrop(maxCrop.size() / 2);
> -	ret = m2m_->output()->setSelection(V4L2_SEL_TGT_CROP, &halfCrop);
> -	if (!ret && halfCrop != maxCrop) {
> +	ret = getCropBounds(m2m_->output(), minCrop, maxCrop);
> +	if (!ret && minCrop != maxCrop) {
>  		features_ |= Feature::InputCrop;
>  
>  		LOG(Converter, Info)
> -- 
> 2.43.0
>