Show a cover letter.

GET /api/covers/25080/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 25080,
    "url": "https://patchwork.libcamera.org/api/covers/25080/?format=api",
    "web_url": "https://patchwork.libcamera.org/cover/25080/",
    "project": {
        "id": 1,
        "url": "https://patchwork.libcamera.org/api/projects/1/?format=api",
        "name": "libcamera",
        "link_name": "libcamera",
        "list_id": "libcamera_core",
        "list_email": "libcamera-devel@lists.libcamera.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": ""
    },
    "msgid": "<20251119132221.2088013-1-stefan.klug@ideasonboard.com>",
    "date": "2025-11-19T13:22:09",
    "name": "[v3,0/4] libipa: agc: Fix constraints yTarget handling and add PWL support",
    "submitter": {
        "id": 184,
        "url": "https://patchwork.libcamera.org/api/people/184/?format=api",
        "name": "Stefan Klug",
        "email": "stefan.klug@ideasonboard.com"
    },
    "mbox": "https://patchwork.libcamera.org/cover/25080/mbox/",
    "series": [
        {
            "id": 5595,
            "url": "https://patchwork.libcamera.org/api/series/5595/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5595",
            "date": "2025-11-19T13:22:09",
            "name": "libipa: agc: Fix constraints yTarget handling and add PWL support",
            "version": 3,
            "mbox": "https://patchwork.libcamera.org/series/5595/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/covers/25080/comments/",
    "headers": {
        "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>",
        "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 D9390BD80A\n\tfor <parsemail@patchwork.libcamera.org>;\n\tWed, 19 Nov 2025 13:22:28 +0000 (UTC)",
            "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id C398160A80;\n\tWed, 19 Nov 2025 14:22:27 +0100 (CET)",
            "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 EEE5A606A0\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tWed, 19 Nov 2025 14:22:25 +0100 (CET)",
            "from ideasonboard.com (unknown\n\t[IPv6:2a00:6020:448c:6c00:5419:7bb:83a3:3d7a])\n\tby perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 263B2EB7;\n\tWed, 19 Nov 2025 14:20:21 +0100 (CET)"
        ],
        "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"Q2jEj8yg\"; dkim-atps=neutral",
        "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1763558421;\n\tbh=EUFF+5Tt1WLXRFmfh6tmFJEPZXiSzTLfnbjhaxha52Y=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=Q2jEj8yg3a6atBx2In9zgozaPVZve4OObr3Lu2NB2QoKlYCZdz2wbC4qIaqoUXLIw\n\tNGOgIZYja5TsKZKVCOwgaTngmb/e7yb0TMgezKNzgDvWIH1I2Dkycqz6xZbd03cScu\n\tiQZUoi6ghcFjlfK+XKLf59zdRvDbX2WzvOtmumDA=",
        "From": "Stefan Klug <stefan.klug@ideasonboard.com>",
        "To": "libcamera-devel@lists.libcamera.org",
        "Cc": "Stefan Klug <stefan.klug@ideasonboard.com>",
        "Subject": "[PATCH v3 0/4] libipa: agc: Fix constraints yTarget handling and add\n\tPWL support",
        "Date": "Wed, 19 Nov 2025 14:22:09 +0100",
        "Message-ID": "<20251119132221.2088013-1-stefan.klug@ideasonboard.com>",
        "X-Mailer": "git-send-email 2.51.0",
        "MIME-Version": "1.0",
        "Content-Transfer-Encoding": "8bit",
        "X-BeenThere": "libcamera-devel@lists.libcamera.org",
        "X-Mailman-Version": "2.1.29",
        "Precedence": "list",
        "List-Id": "<libcamera-devel.lists.libcamera.org>",
        "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>",
        "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>",
        "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>",
        "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>",
        "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>",
        "Errors-To": "libcamera-devel-bounces@lists.libcamera.org",
        "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>"
    },
    "content": "Hi all,\n\nThis series introduces support for specifying the\nrelativeLuminanceTarget based on the current lux level by using a PWL\nfor the mapping. The typical use case is to ensure that images in a\nbright environment are regulated a tad brighter than images taken in a\ndark environment. This is a very subjective setting and should therefore\nbe left to the user/camera designer. Mainlining this feature was already\ntried in [1] but got rejected at that time because there was no direct\nuser of it. Meanwhile the lux algorithm got upstreamed and we have users\nthat actually miss that feature. So I start another try of upstreaming\nit (patch 3).\n\nDuring implementation it turned out that the yTarget of AGC constraints\nnever worked at all. So patche 4 fixes that and also adds PWL support\nfor the constraints which is sensible to do if we support it for the\nrelativeLuminanceTarget.\n\nChanges in v3:\n- Added patch 2 to fix the lux algorith and make it more future proof\n- Added back support for tuning files without relativeLuminanceTarget.\n- Improves \"no lux level\" warning handling\n\nChanges in v2:\n- Dropped patch 1 that implemented Pwl::swap() as the intended use can\n  already be achieved using the autogenerated move assignment operator\nand move constructor together with std::move()\n- Dropped the addition of a initializer_list based constructor to Pwl as\n  this can be achieved in a bit more verbose way already.\n- Added patch 1 that extends the yaml PWL reading code to support plain\n  values. This also simplified the subsequent patches.\n\nBest regards,\nStefan\n\nStefan Klug (4):\n  ipa: libipa: pwl: Allow to parse a plain yaml value as single point\n    PWL\n  ipa: rkisp1: lux: Properly handle frame context and active state\n  ipa: libipa: agc_mean_luminance: Change luminance target to piecewise\n    linear function\n  ipa: libipa: agc_mean_luminance: Fix yTarget handling in constraints\n\n src/ipa/libipa/agc_mean_luminance.cpp | 108 +++++++++++++++++++++-----\n src/ipa/libipa/agc_mean_luminance.h   |  18 +++--\n src/ipa/libipa/pwl.cpp                |   9 +++\n src/ipa/rkisp1/algorithms/agc.cpp     |   1 +\n src/ipa/rkisp1/algorithms/lux.cpp     |  23 ++++--\n src/ipa/rkisp1/algorithms/lux.h       |   3 +\n src/ipa/rkisp1/algorithms/wdr.cpp     |   3 +-\n src/ipa/rkisp1/ipa_context.h          |   4 +\n 8 files changed, 139 insertions(+), 30 deletions(-)"
}