diff options
| author | Jacopo Mondi <jacopo.mondi@ideasonboard.com> | 2023-10-19 16:01:27 +0200 |
|---|---|---|
| committer | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2023-10-23 16:05:59 +0300 |
| commit | b54c935dd764ac3348bcedb9ff67d53a26cfaceb (patch) | |
| tree | ce558e390a37d6a92cde7c77d60f8387f0a4b053 | |
| parent | 250577878bff825516ea5a942aea1b3339acb15c (diff) | |
libcamera: transform: Invert operator*() operands
The current definition of operator*(Transform t1, Transform t0) follows
the function composition notion, where t0 is applied first then t1 is
applied last.
In order to introduce operator*(Orientation, Transform) where a
Transform is applied on top of an Orientation, invert the operand order
of operator*(Transform, Transform) so that usage of operator* with both
Orientation and Transform can be made associative.
For example:
Orientation o;
Transform t = t1 * t2
Orientation o1 = o * t
= o * (t1 * t2) = (o * t1) * t2 = o * t1 * t2
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
| -rw-r--r-- | src/libcamera/camera_sensor.cpp | 4 | ||||
| -rw-r--r-- | src/libcamera/transform.cpp | 22 |
2 files changed, 13 insertions, 13 deletions
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp index 8ff72b42..521a1997 100644 --- a/src/libcamera/camera_sensor.cpp +++ b/src/libcamera/camera_sensor.cpp @@ -1136,7 +1136,7 @@ Transform CameraSensor::validateTransform(Transform *transform) const * Combine the requested transform to compensate the sensor mounting * rotation. */ - Transform combined = *transform * rotationTransform_; + Transform combined = rotationTransform_ * *transform; /* * We combine the platform and user transform, but must "adjust away" @@ -1165,7 +1165,7 @@ Transform CameraSensor::validateTransform(Transform *transform) const * If the sensor can do no transforms, then combined must be * changed to the identity. The only user transform that gives * rise to this is the inverse of the rotation. (Recall that - * combined = transform * rotationTransform.) + * combined = rotationTransform * transform.) */ *transform = -rotationTransform_; combined = Transform::Identity; diff --git a/src/libcamera/transform.cpp b/src/libcamera/transform.cpp index c3059401..9316db00 100644 --- a/src/libcamera/transform.cpp +++ b/src/libcamera/transform.cpp @@ -189,24 +189,24 @@ Input image | | goes to output image | | */ /** - * \brief Compose two transforms together - * \param[in] t1 The second transform - * \param[in] t0 The first transform + * \brief Compose two transforms by applying \a t0 first then \a t1 + * \param[in] t0 The first transform to apply + * \param[in] t1 The second transform to apply * - * Composing transforms follows the usual mathematical convention for - * composing functions. That is, when performing `t1 * t0`, \a t0 is applied - * first, and then \a t1. - * For example, `Transpose * HFlip` performs `HFlip` first and then the - * `Transpose` yielding `Rot270`, as shown below. + * Compose two transforms into a transform that is equivalent to first applying + * \a t0 and then applying \a t1. For example, `HFlip * Transpose` performs + * `HFlip` first and then the `Transpose` yielding `Rot270`, as shown below. ~~~ A-B B-A B-D Input image | | -> HFLip -> | | -> Transpose -> | | = Rot270 C-D D-C A-C ~~~ - * Note that composition is generally non-commutative for Transforms, - * and not the same as XOR-ing the underlying bit representations. + * Note that composition is generally non-commutative for Transforms, and not + * the same as XOR-ing the underlying bit representations. + * + * \return A Transform equivalent to applying \a t0 and then \a t1 */ -Transform operator*(Transform t1, Transform t0) +Transform operator*(Transform t0, Transform t1) { /* * Reorder the operations so that we imagine doing t0's transpose |