{"id":16119,"url":"https://patchwork.libcamera.org/api/patches/16119/?format=json","web_url":"https://patchwork.libcamera.org/patch/16119/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/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":"<20220530142722.57618-13-tomi.valkeinen@ideasonboard.com>","date":"2022-05-30T14:27:18","name":"[libcamera-devel,v4,12/16] Documentation: Add python-bindings.rst","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"c66f04e0243e07c754ba9a1d3e5855ea530f44bf","submitter":{"id":109,"url":"https://patchwork.libcamera.org/api/people/109/?format=json","name":"Tomi Valkeinen","email":"tomi.valkeinen@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/16119/mbox/","series":[{"id":3149,"url":"https://patchwork.libcamera.org/api/series/3149/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=3149","date":"2022-05-30T14:27:06","name":"More misc Python patches","version":4,"mbox":"https://patchwork.libcamera.org/series/3149/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/16119/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/16119/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 B9C12C3276\n\tfor ;\n\tMon, 30 May 2022 14:27:54 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 4096C65653;\n\tMon, 30 May 2022 16:27:54 +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 68E3965635\n\tfor ;\n\tMon, 30 May 2022 16:27:45 +0200 (CEST)","from deskari.lan (91-156-85-209.elisa-laajakaista.fi\n\t[91.156.85.209])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id D20A718ED;\n\tMon, 30 May 2022 16:27:44 +0200 (CEST)"],"DKIM-Signature":["v=1; a=rsa-sha256; c=relaxed/simple; d=libcamera.org;\n\ts=mail; t=1653920874;\n\tbh=O4WPfISxap1qo2Aw7PecJQiEt5HvyOlR1XhKIk0NQgk=;\n\th=To:Date:In-Reply-To:References:Subject:List-Id:List-Unsubscribe:\n\tList-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:\n\tFrom;\n\tb=PeSLrdIJ2SafyY0G2v5A7+1cAdYSkA2qzZw5eHZpNUMLdlygj1/89ilcnn05D7BXk\n\txwiDLUYwCKPlvu+LPDhs8x3cuiYhqSwSYJpYsg1QWo+HECoE4GzpcZMrw1nuRgfYUL\n\tndjf5Idqr94krknjdoZh5xnSLi1kGzOzcWTB3ktI4Lxac8GW2p9jmoDzYRr8c/65IV\n\tt7kUDngCV1FmkqYERnN5OemQ9gYODlNjrh4mYqlQU5Fx1FoSWE4yFdF4ycBPu8o285\n\tfOvByihps7OABQyRQ2tcEVaod4onA0DyFA/a177QdarnnI0ceCi3e/HqhCNytOMnKo\n\tzgA8KuaGLKYNg==","v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1653920865;\n\tbh=O4WPfISxap1qo2Aw7PecJQiEt5HvyOlR1XhKIk0NQgk=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=FoZ1ud/vMZlI/ZIBPTCpHAtqVDtcLK/QdGpamOq3SVMtber7Ual+LKB7a/o1o+hBU\n\ttGbNIwg0QdkdUS+daN8WMVM4mWNpX8+UEBnYXtdOKwugt/ndUgR8PM24mnriQma76a\n\t3l60mep0OaYfhNCywLTOukIyShQwrz9GnJK6a0xI="],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key; \n\tunprotected) header.d=ideasonboard.com\n\theader.i=@ideasonboard.com\n\theader.b=\"FoZ1ud/v\"; dkim-atps=neutral","To":"libcamera-devel@lists.libcamera.org,\n\tDavid Plowman ,\n\tKieran Bingham ,\n\tLaurent Pinchart ,\n\tJacopo Mondi ","Date":"Mon, 30 May 2022 17:27:18 +0300","Message-Id":"<20220530142722.57618-13-tomi.valkeinen@ideasonboard.com>","X-Mailer":"git-send-email 2.34.1","In-Reply-To":"<20220530142722.57618-1-tomi.valkeinen@ideasonboard.com>","References":"<20220530142722.57618-1-tomi.valkeinen@ideasonboard.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH v4 12/16] Documentation: Add\n\tpython-bindings.rst","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":"Tomi Valkeinen via libcamera-devel\n\t","Reply-To":"Tomi Valkeinen ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"Add a basic doc for the Python bindings. While not really proper\ndocumentation yet, the file and the examples should give enough guidance\nfor users who are somewhat familiar with libcamera.\n\nSigned-off-by: Tomi Valkeinen \n---\n Documentation/index.rst | 1 +\n Documentation/meson.build | 1 +\n Documentation/python-bindings.rst | 70 +++++++++++++++++++++++++++++++\n 3 files changed, 72 insertions(+)\n create mode 100644 Documentation/python-bindings.rst","diff":"diff --git a/Documentation/index.rst b/Documentation/index.rst\nindex 0ee10044..43d8b017 100644\n--- a/Documentation/index.rst\n+++ b/Documentation/index.rst\n@@ -22,3 +22,4 @@\n Environment variables \n Sensor driver requirements \n Lens driver requirements \n+ Python Bindings \ndiff --git a/Documentation/meson.build b/Documentation/meson.build\nindex 8e2eacc6..7695bcb1 100644\n--- a/Documentation/meson.build\n+++ b/Documentation/meson.build\n@@ -67,6 +67,7 @@ if sphinx.found()\n 'guides/tracing.rst',\n 'index.rst',\n 'lens_driver_requirements.rst',\n+ 'python-bindings.rst',\n 'sensor_driver_requirements.rst',\n '../README.rst',\n ]\ndiff --git a/Documentation/python-bindings.rst b/Documentation/python-bindings.rst\nnew file mode 100644\nindex 00000000..cfa9ec10\n--- /dev/null\n+++ b/Documentation/python-bindings.rst\n@@ -0,0 +1,70 @@\n+.. SPDX-License-Identifier: CC-BY-SA-4.0\n+\n+.. _python-bindings:\n+\n+Python Bindings for libcamera\n+=============================\n+\n+*WARNING* The bindings are under work, and the API will change.\n+\n+Differences to the C++ API\n+--------------------------\n+\n+As a rule of thumb the bindings try to follow the C++ API when possible. This\n+chapter lists the differences.\n+\n+Mostly these differences fall under two categories:\n+\n+1. Differences caused by the inherent differences between C++ and Python.\n+These differences are usually caused by the use of threads or differences in\n+C++ vs Python memory management.\n+\n+2. Differences caused by the code being work-in-progress. It's not always\n+trivial to create a binding in a satisfying way, and the current bindings\n+contain simplified versions of the C++ API just to get forward. These\n+differences are expected to eventually go away.\n+\n+Coding Style\n+------------\n+\n+The C++ code for the bindings follows the libcamera coding style as much as\n+possible. Note that the indentation does not quite follow the clang-format\n+style, as clang-format makes a mess of the style used.\n+\n+The API visible to the Python side follows the Python style as much as possible.\n+\n+This means that e.g. ``Camera::generateConfiguration`` maps to\n+``Camera.generate_configuration``.\n+\n+CameraManager\n+-------------\n+\n+The Python API provides a singleton CameraManager via ``CameraManager.singleton()``.\n+There is no need to start or stop the CameraManager.\n+\n+Handling Completed Requests\n+---------------------------\n+\n+The Python bindings do not expose the ``Camera::requestCompleted`` signal\n+directly as the signal is invoked from another thread and it has real-time\n+constraints. Instead the bindings will internally queue the completed\n+requests and use an eventfd to inform the user that there are completed\n+requests.\n+\n+The user can wait on the eventfd, and upon getting an event, use\n+``CameraManager.get_ready_requests()`` to clear the eventfd event and to get\n+the completed requests.\n+\n+Controls & Properties\n+---------------------\n+\n+The classes related to controls and properties are rather complex to implement\n+directly in the Python bindings. There are some simplifications on the Python\n+bindings:\n+\n+- There is no ControlValue class. Python objects are automatically converted\n+ to ControlValues and vice versa.\n+- There is no ControlList class. A python dict with ControlId keys and python\n+ object values is used instead.\n+- There is no ControlInfoMap class. A python dict with ControlId keys and\n+ ControlInfo values is used instead.\n","prefixes":["libcamera-devel","v4","12/16"]}