[PATCH v3 2/4] libcamera: converter_v4l2_m2m: Support crop selection

[Kieran Bingham]

Quoting Umang Jain (2024-06-25 07:23:25)
> Add a helper to set selection rectangle on the video node
> to support cropping and scaling capabilites.
> 
> Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
> ---
>  .../internal/converter/converter_v4l2_m2m.h   |  5 ++++
>  .../converter/converter_v4l2_m2m.cpp          | 27 +++++++++++++++++++
>  2 files changed, 32 insertions(+)
> 
> diff --git a/include/libcamera/internal/converter/converter_v4l2_m2m.h b/include/libcamera/internal/converter/converter_v4l2_m2m.h
> index b9e59899..846e9f9e 100644
> --- a/include/libcamera/internal/converter/converter_v4l2_m2m.h
> +++ b/include/libcamera/internal/converter/converter_v4l2_m2m.h
> @@ -30,6 +30,7 @@ class Size;
>  class SizeRange;
>  class Stream;
>  struct StreamConfiguration;
> +class Rectangle;
>  class V4L2M2MDevice;
>  
>  class V4L2M2MConverter : public Converter
> @@ -57,6 +58,8 @@ public:
>         int queueBuffers(FrameBuffer *input,
>                          const std::map<const Stream *, FrameBuffer *> &outputs);
>  
> +       int setSelection(const Stream *stream, unsigned int target, Rectangle *rect);
> +
>  private:
>         class V4L2M2MStream : protected Loggable
>         {
> @@ -75,6 +78,8 @@ private:
>  
>                 int queueBuffers(FrameBuffer *input, FrameBuffer *output);
>  
> +               int setSelection(unsigned int target, Rectangle *rect);
> +
>         protected:
>                 std::string logPrefix() const override;
>  
> diff --git a/src/libcamera/converter/converter_v4l2_m2m.cpp b/src/libcamera/converter/converter_v4l2_m2m.cpp
> index 2e77872e..c323f677 100644
> --- a/src/libcamera/converter/converter_v4l2_m2m.cpp
> +++ b/src/libcamera/converter/converter_v4l2_m2m.cpp
> @@ -155,6 +155,15 @@ int V4L2M2MConverter::V4L2M2MStream::queueBuffers(FrameBuffer *input, FrameBuffe
>         return 0;
>  }
>  
> +int V4L2M2MConverter::V4L2M2MStream::setSelection(unsigned int target, Rectangle *rect)
> +{
> +       int ret = m2m_->output()->setSelection(target, rect);

Can selections ever be expected to be set on the input()?

> +       if (ret < 0)
> +               return ret;
> +
> +       return 0;
> +}
> +
>  std::string V4L2M2MConverter::V4L2M2MStream::logPrefix() const
>  {
>         return stream_->configuration().toString();
> @@ -374,6 +383,24 @@ int V4L2M2MConverter::exportBuffers(const Stream *stream, unsigned int count,
>         return iter->second->exportBuffers(count, buffers);
>  }
>  
> +/**
> + * \brief Set a selection rectangle \a rect for \a target
> + * \param[in] stream Pointer to output stream
> + * \param[in] target The selection target defined by the V4L2_SEL_TGT_* flags
> + * \param[inout] rect The selection rectangle to be applied
> + *
> + * \return 0 on success or a negative error code otherwise
> + */
> +int V4L2M2MConverter::setSelection(const Stream *stream, unsigned int target,
> +                                  Rectangle *rect)

I'm not yet sure how far up the V4L2 types should be transferred in this, but as the class name is V4L2M2M - I think we're still good here.

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> +{
> +       auto iter = streams_.find(stream);
> +       if (iter == streams_.end())
> +               return -EINVAL;
> +
> +       return iter->second->setSelection(target, rect);
> +}
> +
>  /**
>   * \copydoc libcamera::Converter::start
>   */
> -- 
> 2.44.0
>