{"id":18868,"url":"https://patchwork.libcamera.org/api/1.1/patches/18868/?format=json","web_url":"https://patchwork.libcamera.org/patch/18868/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20230724071101.5256-7-jacopo.mondi@ideasonboard.com>","date":"2023-07-24T07:10:57","name":"[libcamera-devel,v4,06/10] libcamera: transform: Invert operator*() operands","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"ca1c8c2156d8dbd8c5c2b9d0a2ae666c12257f56","submitter":{"id":143,"url":"https://patchwork.libcamera.org/api/1.1/people/143/?format=json","name":"Jacopo Mondi","email":"jacopo.mondi@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/18868/mbox/","series":[{"id":3981,"url":"https://patchwork.libcamera.org/api/1.1/series/3981/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=3981","date":"2023-07-24T07:10:51","name":"libcamera: Replace CameraConfiguration::transform","version":4,"mbox":"https://patchwork.libcamera.org/series/3981/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/18868/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/18868/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 4C54DBDC71\n\tfor ;\n\tMon, 24 Jul 2023 07:11:31 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id F1125628DB;\n\tMon, 24 Jul 2023 09:11:30 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 242DC628C0\n\tfor ;\n\tMon, 24 Jul 2023 09:11:25 +0200 (CEST)","from uno.localdomain (mob-5-91-20-233.net.vodafone.it\n\t[5.91.20.233])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 345EF2C6;\n\tMon, 24 Jul 2023 09:10:27 +0200 (CEST)"],"DKIM-Signature":["v=1; 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dkim=pass (1024-bit key; \n\tunprotected) header.d=ideasonboard.com\n\theader.i=@ideasonboard.com\n\theader.b=\"BR8P++4y\"; dkim-atps=neutral","To":"libcamera-devel@lists.libcamera.org","Date":"Mon, 24 Jul 2023 09:10:57 +0200","Message-Id":"<20230724071101.5256-7-jacopo.mondi@ideasonboard.com>","X-Mailer":"git-send-email 2.40.1","In-Reply-To":"<20230724071101.5256-1-jacopo.mondi@ideasonboard.com>","References":"<20230724071101.5256-1-jacopo.mondi@ideasonboard.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH v4 06/10] libcamera: transform: Invert\n\toperator*() operands","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","From":"Jacopo Mondi via libcamera-devel ","Reply-To":"Jacopo Mondi ","Cc":"Jacopo Mondi ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"The current definition of operator*(Transform t1, Transform t0) follows\nthe function composition notion, where t0 is applied first then t1 is\napplied last.\n\nIn order to introduce operator*(Orientation, Transform) where a\nTransform is applied on top of an Orientation, invert the operand order\nof operator*(Transform, Transform) so that usage of operator* with both\nOrientation and Transform can be made associative.\n\nFor example:\n\nOrientation o;\nTransform t = t1 * t2\nOrientation o1 = o * t\n\t = o * (t1 * t2) = (o * t1) * t2 = o * t1 * t2\n\nSigned-off-by: Jacopo Mondi \nReviewed-by: David Plowman \n---\n src/libcamera/camera_sensor.cpp | 4 ++--\n src/libcamera/transform.cpp | 19 +++++++++++--------\n 2 files changed, 13 insertions(+), 10 deletions(-)","diff":"diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp\nindex 3ba364c44a40..038d8b959072 100644\n--- a/src/libcamera/camera_sensor.cpp\n+++ b/src/libcamera/camera_sensor.cpp\n@@ -1051,7 +1051,7 @@ Transform CameraSensor::validateTransform(Transform *transform) const\n \t * Combine the requested transform to compensate the sensor mounting\n \t * rotation.\n \t */\n-\tTransform combined = *transform * rotationTransform_;\n+\tTransform combined = rotationTransform_ * *transform;\n \n \t/*\n \t * We combine the platform and user transform, but must \"adjust away\"\n@@ -1080,7 +1080,7 @@ Transform CameraSensor::validateTransform(Transform *transform) const\n \t\t * If the sensor can do no transforms, then combined must be\n \t\t * changed to the identity. The only user transform that gives\n \t\t * rise to this is the inverse of the rotation. (Recall that\n-\t\t * combined = transform * rotationTransform.)\n+\t\t * combined = rotationTransform * transform.)\n \t\t */\n \t\t*transform = -rotationTransform_;\n \t\tcombined = Transform::Identity;\ndiff --git a/src/libcamera/transform.cpp b/src/libcamera/transform.cpp\nindex c70cac3f14ee..d192d63d9290 100644\n--- a/src/libcamera/transform.cpp\n+++ b/src/libcamera/transform.cpp\n@@ -189,14 +189,17 @@ Input image | | goes to output image | |\n */\n \n /**\n- * \\brief Compose two transforms together\n- * \\param[in] t1 The second transform\n- * \\param[in] t0 The first transform\n+ * \\brief Compose two transforms by applying \\a t0 first then \\a t1\n+ * \\param[in] t0 The first transform to apply\n+ * \\param[in] t1 The second transform to apply\n+ *\n+ * Compose two transforms by applying \\a t1 after \\a t0. The operation\n+ * is conceptually equivalent to the canonical notion of function composition,\n+ * with inverse order of operands. If in the canonical function composition\n+ * notation \"f * g\" equals to \"f(g())\", the notation for Transforms composition\n+ * \"t0 * t1\" equals to \"t1(t0()))\" where \\a t0 is applied first, then \\a t1.\n *\n- * Composing transforms follows the usual mathematical convention for\n- * composing functions. That is, when performing `t1 * t0`, \\a t0 is applied\n- * first, and then \\a t1.\n- * For example, `Transpose * HFlip` performs `HFlip` first and then the\n+ * For example, `HFlip * Transpose` performs `HFlip` first and then the\n * `Transpose` yielding `Rot270`, as shown below.\n ~~~\n A-B B-A B-D\n@@ -206,7 +209,7 @@ Input image | | -> HFLip -> | | -> Transpose -> | | = Rot270\n * Note that composition is generally non-commutative for Transforms,\n * and not the same as XOR-ing the underlying bit representations.\n */\n-Transform operator*(Transform t1, Transform t0)\n+Transform operator*(Transform t0, Transform t1)\n {\n \t/*\n \t * Reorder the operations so that we imagine doing t0's transpose\n","prefixes":["libcamera-devel","v4","06/10"]}