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1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later2.. c:namespace:: V4L3 4.. _VIDIOC_SUBDEV_G_CROP:5 6************************************************7ioctl VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP8************************************************9 10Name11====12 13VIDIOC_SUBDEV_G_CROP - VIDIOC_SUBDEV_S_CROP - Get or set the crop rectangle on a subdev pad14 15Synopsis16========17 18.. c:macro:: VIDIOC_SUBDEV_G_CROP19 20``int ioctl(int fd, VIDIOC_SUBDEV_G_CROP, struct v4l2_subdev_crop *argp)``21 22.. c:macro:: VIDIOC_SUBDEV_S_CROP23 24``int ioctl(int fd, VIDIOC_SUBDEV_S_CROP, const struct v4l2_subdev_crop *argp)``25 26Arguments27=========28 29``fd``30 File descriptor returned by :c:func:`open()`.31 32``argp``33 Pointer to struct :c:type:`v4l2_subdev_crop`.34 35Description36===========37 38.. note::39 40 This is an :ref:`obsolete` interface and may be removed in the future. It is41 superseded by :ref:`the selection API <VIDIOC_SUBDEV_G_SELECTION>`. No new42 extensions to the :c:type:`v4l2_subdev_crop` structure will be accepted.43 44To retrieve the current crop rectangle applications set the ``pad``45field of a struct :c:type:`v4l2_subdev_crop` to the46desired pad number as reported by the media API and the ``which`` field47to ``V4L2_SUBDEV_FORMAT_ACTIVE``. They then call the48``VIDIOC_SUBDEV_G_CROP`` ioctl with a pointer to this structure. The49driver fills the members of the ``rect`` field or returns ``EINVAL`` error50code if the input arguments are invalid, or if cropping is not supported51on the given pad.52 53To change the current crop rectangle applications set both the ``pad``54and ``which`` fields and all members of the ``rect`` field. They then55call the ``VIDIOC_SUBDEV_S_CROP`` ioctl with a pointer to this56structure. The driver verifies the requested crop rectangle, adjusts it57based on the hardware capabilities and configures the device. Upon58return the struct :c:type:`v4l2_subdev_crop`59contains the current format as would be returned by a60``VIDIOC_SUBDEV_G_CROP`` call.61 62Applications can query the device capabilities by setting the ``which``63to ``V4L2_SUBDEV_FORMAT_TRY``. When set, 'try' crop rectangles are not64applied to the device by the driver, but are mangled exactly as active65crop rectangles and stored in the sub-device file handle. Two66applications querying the same sub-device would thus not interact with67each other.68 69If the subdev device node has been registered in read-only mode, calls to70``VIDIOC_SUBDEV_S_CROP`` are only valid if the ``which`` field is set to71``V4L2_SUBDEV_FORMAT_TRY``, otherwise an error is returned and the errno72variable is set to ``-EPERM``.73 74Drivers must not return an error solely because the requested crop75rectangle doesn't match the device capabilities. They must instead76modify the rectangle to match what the hardware can provide. The77modified format should be as close as possible to the original request.78 79.. c:type:: v4l2_subdev_crop80 81.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|82 83.. flat-table:: struct v4l2_subdev_crop84 :header-rows: 085 :stub-columns: 086 :widths: 1 1 287 88 * - __u3289 - ``pad``90 - Pad number as reported by the media framework.91 * - __u3292 - ``which``93 - Crop rectangle to get or set, from enum94 :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.95 * - struct :c:type:`v4l2_rect`96 - ``rect``97 - Crop rectangle boundaries, in pixels.98 * - __u3299 - ``stream``100 - Stream identifier.101 * - __u32102 - ``reserved``\ [7]103 - Reserved for future extensions. Applications and drivers must set104 the array to zero.105 106Return Value107============108 109On success 0 is returned, on error -1 and the ``errno`` variable is set110appropriately. The generic error codes are described at the111:ref:`Generic Error Codes <gen-errors>` chapter.112 113EBUSY114 The crop rectangle can't be changed because the pad is currently115 busy. This can be caused, for instance, by an active video stream on116 the pad. The ioctl must not be retried without performing another117 action to fix the problem first. Only returned by118 ``VIDIOC_SUBDEV_S_CROP``119 120EINVAL121 The struct :c:type:`v4l2_subdev_crop` ``pad`` references a non-existing pad,122 the ``which`` field has an unsupported value, or cropping is not supported123 on the given subdev pad.124 125EPERM126 The ``VIDIOC_SUBDEV_S_CROP`` ioctl has been called on a read-only subdevice127 and the ``which`` field is set to ``V4L2_SUBDEV_FORMAT_ACTIVE``.128