libcamera: properties: Make 'Rotation' the mounting rotation

Specify in the documentation that properties::Rotation specifies the mounting rotation of the camera module. This avoids confusion with the image orientation which is instead expressed by CameraConfiguration::orientation. For this reason, do not compensate the Rotation property when initializing the CameraSensor class but report the value of V4L2_CID_CAMERA_SENSOR_ROTATION or 0 if the control is not available. Signed-off-by: Jacopo Mondi <[email protected]> Reviewed-by: David Plowman <[email protected]> Reviewed-by: Laurent Pinchart <[email protected]> Signed-off-by: Laurent Pinchart <[email protected]>
lukeclements · Oct 23, 2023 · 568569b · 568569b
1 parent 891720a
commit 568569b
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diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
@@ -433,11 +433,11 @@ int CameraSensor::initProperties()
 
 	/* Retrieve and register properties from the kernel interface. */
 	const ControlInfoMap &controls = subdev_->controls();
-	int32_t propertyValue;
 
 	const auto &orientation = controls.find(V4L2_CID_CAMERA_ORIENTATION);
 	if (orientation != controls.end()) {
 		int32_t v4l2Orientation = orientation->second.def().get<int32_t>();
+		int32_t propertyValue;
 
 		switch (v4l2Orientation) {
 		default:
@@ -462,7 +462,7 @@ int CameraSensor::initProperties()
 
 	const auto &rotationControl = controls.find(V4L2_CID_CAMERA_SENSOR_ROTATION);
 	if (rotationControl != controls.end()) {
-		propertyValue = rotationControl->second.def().get<int32_t>();
+		int32_t propertyValue = rotationControl->second.def().get<int32_t>();
 
 		/*
 		 * Cache the Transform associated with the camera mounting
@@ -477,20 +477,11 @@ int CameraSensor::initProperties()
 			rotationTransform_ = Transform::Identity;
 		}
 
-		/*
-		 * Adjust property::Rotation as validateTransform() compensates
-		 * for the mounting rotation. However, as a camera sensor can
-		 * only compensate rotations by applying H/VFlips, only rotation
-		 * of 180 degrees are automatically compensated. The other valid
-		 * rotations (Rot90 and Rot270) require transposition, which the
-		 * camera sensor cannot perform, so leave them untouched.
-		 */
-		if (propertyValue == 180 && supportFlips_)
-			propertyValue = 0;
 		properties_.set(properties::Rotation, propertyValue);
 	} else {
 		LOG(CameraSensor, Warning)
 			<< "Rotation control not available, default to 0 degrees";
+		properties_.set(properties::Rotation, 0);
 		rotationTransform_ = Transform::Identity;
 	}
 

diff --git a/src/libcamera/property_ids.yaml b/src/libcamera/property_ids.yaml
@@ -29,10 +29,10 @@ controls:
   - Rotation:
       type: int32_t
       description: |
-        The camera rotation is expressed as the angular difference in degrees
-        between two reference systems, one relative to the camera module, and
-        one defined on the external world scene to be captured when projected
-        on the image sensor pixel array.
+        The camera physical mounting rotation. It is expressed as the angular
+        difference in degrees between two reference systems, one relative to the
+        camera module, and one defined on the external world scene to be
+        captured when projected on the image sensor pixel array.
 
         A camera sensor has a 2-dimensional reference system 'Rc' defined by
         its pixel array read-out order. The origin is set to the first pixel