1.. Permission is granted to copy, distribute and/or modify this 2.. document under the terms of the GNU Free Documentation License, 3.. Version 1.1 or any later version published by the Free Software 4.. Foundation, with no Invariant Sections, no Front-Cover Texts 5.. and no Back-Cover Texts. A copy of the license is included at 6.. Documentation/userspace-api/media/fdl-appendix.rst. 7.. 8.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections 9 10.. _VIDIOC_SUBDEV_G_CROP: 11 12************************************************ 13ioctl VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP 14************************************************ 15 16Name 17==== 18 19VIDIOC_SUBDEV_G_CROP - VIDIOC_SUBDEV_S_CROP - Get or set the crop rectangle on a subdev pad 20 21 22Synopsis 23======== 24 25.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_CROP, struct v4l2_subdev_crop *argp ) 26 :name: VIDIOC_SUBDEV_G_CROP 27 28.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_CROP, const struct v4l2_subdev_crop *argp ) 29 :name: VIDIOC_SUBDEV_S_CROP 30 31 32Arguments 33========= 34 35``fd`` 36 File descriptor returned by :ref:`open() <func-open>`. 37 38``argp`` 39 Pointer to struct :c:type:`v4l2_subdev_crop`. 40 41 42Description 43=========== 44 45.. note:: 46 47 This is an :ref:`obsolete` interface and may be removed 48 in the future. It is superseded by 49 :ref:`the selection API <VIDIOC_SUBDEV_G_SELECTION>`. 50 51To retrieve the current crop rectangle applications set the ``pad`` 52field of a struct :c:type:`v4l2_subdev_crop` to the 53desired pad number as reported by the media API and the ``which`` field 54to ``V4L2_SUBDEV_FORMAT_ACTIVE``. They then call the 55``VIDIOC_SUBDEV_G_CROP`` ioctl with a pointer to this structure. The 56driver fills the members of the ``rect`` field or returns ``EINVAL`` error 57code if the input arguments are invalid, or if cropping is not supported 58on the given pad. 59 60To change the current crop rectangle applications set both the ``pad`` 61and ``which`` fields and all members of the ``rect`` field. They then 62call the ``VIDIOC_SUBDEV_S_CROP`` ioctl with a pointer to this 63structure. The driver verifies the requested crop rectangle, adjusts it 64based on the hardware capabilities and configures the device. Upon 65return the struct :c:type:`v4l2_subdev_crop` 66contains the current format as would be returned by a 67``VIDIOC_SUBDEV_G_CROP`` call. 68 69Applications can query the device capabilities by setting the ``which`` 70to ``V4L2_SUBDEV_FORMAT_TRY``. When set, 'try' crop rectangles are not 71applied to the device by the driver, but are mangled exactly as active 72crop rectangles and stored in the sub-device file handle. Two 73applications querying the same sub-device would thus not interact with 74each other. 75 76If the subdev device node has been registered in read-only mode, calls to 77``VIDIOC_SUBDEV_S_CROP`` are only valid if the ``which`` field is set to 78``V4L2_SUBDEV_FORMAT_TRY``, otherwise an error is returned and the errno 79variable is set to ``-EPERM``. 80 81Drivers must not return an error solely because the requested crop 82rectangle doesn't match the device capabilities. They must instead 83modify the rectangle to match what the hardware can provide. The 84modified format should be as close as possible to the original request. 85 86 87.. c:type:: v4l2_subdev_crop 88 89.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 90 91.. flat-table:: struct v4l2_subdev_crop 92 :header-rows: 0 93 :stub-columns: 0 94 :widths: 1 1 2 95 96 * - __u32 97 - ``pad`` 98 - Pad number as reported by the media framework. 99 * - __u32 100 - ``which`` 101 - Crop rectangle to get or set, from enum 102 :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. 103 * - struct :c:type:`v4l2_rect` 104 - ``rect`` 105 - Crop rectangle boundaries, in pixels. 106 * - __u32 107 - ``reserved``\ [8] 108 - Reserved for future extensions. Applications and drivers must set 109 the array to zero. 110 111 112Return Value 113============ 114 115On success 0 is returned, on error -1 and the ``errno`` variable is set 116appropriately. The generic error codes are described at the 117:ref:`Generic Error Codes <gen-errors>` chapter. 118 119EBUSY 120 The crop rectangle can't be changed because the pad is currently 121 busy. This can be caused, for instance, by an active video stream on 122 the pad. The ioctl must not be retried without performing another 123 action to fix the problem first. Only returned by 124 ``VIDIOC_SUBDEV_S_CROP`` 125 126EINVAL 127 The struct :c:type:`v4l2_subdev_crop` ``pad`` 128 references a non-existing pad, the ``which`` field references a 129 non-existing format, or cropping is not supported on the given 130 subdev pad. 131 132EPERM 133 The ``VIDIOC_SUBDEV_S_CROP`` ioctl has been called on a read-only subdevice 134 and the ``which`` field is set to ``V4L2_SUBDEV_FORMAT_ACTIVE``. 135