[libcamera-devel] [RFC PATCH v2 1/3] android: Add helpers for setting android metadata from libcamera controls

[Laurent Pinchart]

Hi Paul,

Thank you for the patch.

On Thu, Jun 24, 2021 at 07:50:52PM +0900, Paul Elder wrote:
> Add helpers for setting android metadata from libcamera controls.
> 
> There are two versions, for scalars and collections, both of which take
> a default value to fill in the android control if the libcamera control
> is not found. A version for scalars exists for no default, to not set
> the android control at all if it is not found in libcamera. The last one
> requires the type to be specified, but the other two do not.
> 
> The versions that take a default value return the value that was set in
> the android metadata.
> 
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> 
> ---
> New in v2
> 
> TODO: make ControlList versions so that we can use them in result
> metadata
> ---
>  src/android/camera_capabilities.cpp | 81 +++++++++++++++++++++++++++++
>  1 file changed, 81 insertions(+)
> 
> diff --git a/src/android/camera_capabilities.cpp b/src/android/camera_capabilities.cpp
> index 00224a6d..7d795bf5 100644
> --- a/src/android/camera_capabilities.cpp
> +++ b/src/android/camera_capabilities.cpp
> @@ -113,6 +113,87 @@ const std::map<int, const Camera3Format> camera3FormatsMap = {
>  	},
>  };
>  
> +enum ControlRange {
> +	Min,
> +	Def,
> +	Max,
> +};
> +
> +template<typename T,
> +	 std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
> +void setMetadata(CameraMetadata *metadata, uint32_t tag,
> +		 const ControlInfoMap &controlsInfo, const ControlId *control,
> +		 enum ControlRange controlRange)
> +{
> +	const auto &info = controlsInfo.find(control);
> +	if (info == controlsInfo.end())
> +		return;
> +
> +	T ret;
> +	switch (controlRange) {
> +	case Min:
> +		ret = info->second.min().get<T>();
> +		break;
> +	case Def:
> +		ret = info->second.def().get<T>();
> +		break;
> +	case Max:
> +		ret = info->second.max().get<T>();
> +		break;
> +	}
> +
> +	metadata->addEntry(tag, ret);
> +	return;
> +}
> +
> +template<typename T,
> +	 std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
> +T setMetadata(CameraMetadata *metadata, uint32_t tag,
> +	      const ControlInfoMap &controlsInfo, const ControlId *control,
> +	      const T defaultValue, enum ControlRange controlRange)
> +{
> +	T ret = defaultValue;
> +
> +	const auto &info = controlsInfo.find(control);
> +	if (info != controlsInfo.end()) {
> +		switch (controlRange) {
> +		case Min:
> +			ret = info->second.min().get<T>();
> +			break;
> +		case Def:
> +			ret = info->second.def().get<T>();
> +			break;
> +		case Max:
> +			ret = info->second.max().get<T>();
> +			break;
> +		}
> +	}
> +
> +	metadata->addEntry(tag, ret);
> +	return ret;
> +}
> +
> +template<typename S,
> +	 typename T = typename S::value_type>
> +S setMetadata(CameraMetadata *metadata, uint32_t tag,
> +	      const ControlInfoMap &controlsInfo, const ControlId *control,
> +	      const S &defaultVector)

If S is required to be a vector, could this be

template<typename T>,
std::vector<T> setMetadata(CameraMetadata *metadata, uint32_t tag,
			   const ControlInfoMap &controlsInfo,
			   const ControlId *control,
			   const std::vector<T> &defaultVector)

> +{
> +	std::vector<T> ret = {};
> +
> +	const auto &info = controlsInfo.find(control);
> +	if (info != controlsInfo.end()) {
> +		ret.reserve(info->second.values().size());
> +		for (const auto &value : info->second.values())
> +			ret.push_back(value.get<T>());
> +	} else {
> +		ret = defaultVector;
> +	}
> +
> +	metadata->addEntry(tag, ret);
> +	return ret;
> +}
> +
>  } /* namespace */
>  
>  int CameraCapabilities::initialize(std::shared_ptr<libcamera::Camera> camera,

-- 
Regards,

Laurent Pinchart