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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
af4a4d0d | 3 | .. _VIDIOC_SUBDEV_G_SELECTION: |
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4 | |
5 | ********************************************************** | |
6 | ioctl VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION | |
7 | ********************************************************** | |
8 | ||
15e7d615 | 9 | Name |
586027ce | 10 | ==== |
5377d91f | 11 | |
586027ce | 12 | VIDIOC_SUBDEV_G_SELECTION - VIDIOC_SUBDEV_S_SELECTION - Get or set selection rectangles on a subdev pad |
5377d91f | 13 | |
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14 | |
15 | Synopsis | |
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16 | ======== |
17 | ||
b7e67f6c | 18 | .. cpp:function:: int ioctl( int fd, int request, struct v4l2_subdev_selection *argp ) |
5377d91f | 19 | |
586027ce | 20 | |
15e7d615 | 21 | Arguments |
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22 | ========= |
23 | ||
24 | ``fd`` | |
25 | File descriptor returned by :ref:`open() <func-open>`. | |
26 | ||
27 | ``request`` | |
28 | VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION | |
29 | ||
30 | ``argp`` | |
31 | ||
32 | ||
15e7d615 | 33 | Description |
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34 | =========== |
35 | ||
36 | The selections are used to configure various image processing | |
37 | functionality performed by the subdevs which affect the image size. This | |
38 | currently includes cropping, scaling and composition. | |
39 | ||
40 | The selection API replaces | |
af4a4d0d | 41 | :ref:`the old subdev crop API <VIDIOC_SUBDEV_G_CROP>`. All the |
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42 | function of the crop API, and more, are supported by the selections API. |
43 | ||
44 | See :ref:`subdev` for more information on how each selection target | |
45 | affects the image processing pipeline inside the subdevice. | |
46 | ||
47 | ||
48 | Types of selection targets | |
49 | -------------------------- | |
50 | ||
51 | There are two types of selection targets: actual and bounds. The actual | |
52 | targets are the targets which configure the hardware. The BOUNDS target | |
53 | will return a rectangle that contain all possible actual rectangles. | |
54 | ||
55 | ||
56 | Discovering supported features | |
57 | ------------------------------ | |
58 | ||
59 | To discover which targets are supported, the user can perform | |
60 | ``VIDIOC_SUBDEV_G_SELECTION`` on them. Any unsupported target will | |
61 | return ``EINVAL``. | |
62 | ||
63 | Selection targets and flags are documented in | |
64 | :ref:`v4l2-selections-common`. | |
65 | ||
66 | ||
67 | .. _v4l2-subdev-selection: | |
68 | ||
69 | .. flat-table:: struct v4l2_subdev_selection | |
70 | :header-rows: 0 | |
71 | :stub-columns: 0 | |
72 | :widths: 1 1 2 | |
73 | ||
74 | ||
75 | - .. row 1 | |
76 | ||
77 | - __u32 | |
78 | ||
79 | - ``which`` | |
80 | ||
81 | - Active or try selection, from enum | |
0579e6e3 | 82 | :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. |
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83 | |
84 | - .. row 2 | |
85 | ||
86 | - __u32 | |
87 | ||
88 | - ``pad`` | |
89 | ||
90 | - Pad number as reported by the media framework. | |
91 | ||
92 | - .. row 3 | |
93 | ||
94 | - __u32 | |
95 | ||
96 | - ``target`` | |
97 | ||
98 | - Target selection rectangle. See :ref:`v4l2-selections-common`. | |
99 | ||
100 | - .. row 4 | |
101 | ||
102 | - __u32 | |
103 | ||
104 | - ``flags`` | |
105 | ||
106 | - Flags. See :ref:`v4l2-selection-flags`. | |
107 | ||
108 | - .. row 5 | |
109 | ||
110 | - struct :ref:`v4l2_rect <v4l2-rect>` | |
111 | ||
112 | - ``r`` | |
113 | ||
114 | - Selection rectangle, in pixels. | |
115 | ||
116 | - .. row 6 | |
117 | ||
118 | - __u32 | |
119 | ||
8968da9b | 120 | - ``reserved``\ [8] |
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121 | |
122 | - Reserved for future extensions. Applications and drivers must set | |
0579e6e3 | 123 | the array to zero. |
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124 | |
125 | ||
15e7d615 | 126 | Return Value |
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127 | ============ |
128 | ||
129 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
130 | appropriately. The generic error codes are described at the | |
131 | :ref:`Generic Error Codes <gen-errors>` chapter. | |
132 | ||
133 | EBUSY | |
134 | The selection rectangle can't be changed because the pad is | |
135 | currently busy. This can be caused, for instance, by an active video | |
136 | stream on the pad. The ioctl must not be retried without performing | |
137 | another action to fix the problem first. Only returned by | |
138 | ``VIDIOC_SUBDEV_S_SELECTION`` | |
139 | ||
140 | EINVAL | |
141 | The struct :ref:`v4l2_subdev_selection <v4l2-subdev-selection>` | |
142 | ``pad`` references a non-existing pad, the ``which`` field | |
143 | references a non-existing format, or the selection target is not | |
144 | supported on the given subdev pad. |