[libcamera-devel] [PATCH v2 4/9] libcamera: properties: Make 'Rotation' the mounting rotation

[Jacopo Mondi]

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 <jacopo.mondi at ideasonboard.com>
---
 src/libcamera/camera_sensor.cpp | 11 +----------
 src/libcamera/property_ids.yaml |  8 ++++----
 2 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index 9a033459742f..3ba364c44a40 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -476,20 +476,11 @@ 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, propertyValue);
 		rotationTransform_ = Transform::Identity;
 	}
 
diff --git a/src/libcamera/property_ids.yaml b/src/libcamera/property_ids.yaml
index 5bddafc29364..fb53081c1bd2 100644
--- 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, 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
-- 
2.40.1