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

[Paul Elder]

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)
+{
+	S 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,
-- 
2.27.0