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_SELECTION: 11 12********************************************************** 13ioctl VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION 14********************************************************** 15 16Name 17==== 18 19VIDIOC_SUBDEV_G_SELECTION - VIDIOC_SUBDEV_S_SELECTION - Get or set selection rectangles on a subdev pad 20 21 22Synopsis 23======== 24 25.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_SELECTION, struct v4l2_subdev_selection *argp ) 26 :name: VIDIOC_SUBDEV_G_SELECTION 27 28.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_SELECTION, struct v4l2_subdev_selection *argp ) 29 :name: VIDIOC_SUBDEV_S_SELECTION 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_selection`. 40 41 42Description 43=========== 44 45The selections are used to configure various image processing 46functionality performed by the subdevs which affect the image size. This 47currently includes cropping, scaling and composition. 48 49The selection API replaces 50:ref:`the old subdev crop API <VIDIOC_SUBDEV_G_CROP>`. All the 51function of the crop API, and more, are supported by the selections API. 52 53See :ref:`subdev` for more information on how each selection target 54affects the image processing pipeline inside the subdevice. 55 56 57Types of selection targets 58-------------------------- 59 60There are two types of selection targets: actual and bounds. The actual 61targets are the targets which configure the hardware. The BOUNDS target 62will return a rectangle that contain all possible actual rectangles. 63 64 65Discovering supported features 66------------------------------ 67 68To discover which targets are supported, the user can perform 69``VIDIOC_SUBDEV_G_SELECTION`` on them. Any unsupported target will 70return ``EINVAL``. 71 72Selection targets and flags are documented in 73:ref:`v4l2-selections-common`. 74 75 76.. c:type:: v4l2_subdev_selection 77 78.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 79 80.. flat-table:: struct v4l2_subdev_selection 81 :header-rows: 0 82 :stub-columns: 0 83 :widths: 1 1 2 84 85 * - __u32 86 - ``which`` 87 - Active or try selection, from enum 88 :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. 89 * - __u32 90 - ``pad`` 91 - Pad number as reported by the media framework. 92 * - __u32 93 - ``target`` 94 - Target selection rectangle. See :ref:`v4l2-selections-common`. 95 * - __u32 96 - ``flags`` 97 - Flags. See :ref:`v4l2-selection-flags`. 98 * - struct :c:type:`v4l2_rect` 99 - ``r`` 100 - Selection rectangle, in pixels. 101 * - __u32 102 - ``reserved``\ [8] 103 - Reserved for future extensions. Applications and drivers must set 104 the array to zero. 105 106 107Return Value 108============ 109 110On success 0 is returned, on error -1 and the ``errno`` variable is set 111appropriately. The generic error codes are described at the 112:ref:`Generic Error Codes <gen-errors>` chapter. 113 114EBUSY 115 The selection rectangle can't be changed because the pad is 116 currently busy. This can be caused, for instance, by an active video 117 stream on the pad. The ioctl must not be retried without performing 118 another action to fix the problem first. Only returned by 119 ``VIDIOC_SUBDEV_S_SELECTION`` 120 121EINVAL 122 The struct :c:type:`v4l2_subdev_selection` 123 ``pad`` references a non-existing pad, the ``which`` field 124 references a non-existing format, or the selection target is not 125 supported on the given subdev pad. 126