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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
af4a4d0d | 3 | .. _VIDIOC_SUBDEV_G_CROP: |
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4 | |
5 | ************************************************ | |
6 | ioctl VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP | |
7 | ************************************************ | |
8 | ||
15e7d615 | 9 | Name |
586027ce | 10 | ==== |
5377d91f | 11 | |
586027ce | 12 | VIDIOC_SUBDEV_G_CROP - VIDIOC_SUBDEV_S_CROP - Get or set the crop rectangle on a subdev pad |
5377d91f | 13 | |
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14 | |
15 | Synopsis | |
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16 | ======== |
17 | ||
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18 | .. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_CROP, struct v4l2_subdev_crop *argp ) |
19 | :name: VIDIOC_SUBDEV_G_CROP | |
5377d91f | 20 | |
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21 | .. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_CROP, const struct v4l2_subdev_crop *argp ) |
22 | :name: VIDIOC_SUBDEV_S_CROP | |
5377d91f | 23 | |
586027ce | 24 | |
15e7d615 | 25 | Arguments |
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26 | ========= |
27 | ||
28 | ``fd`` | |
29 | File descriptor returned by :ref:`open() <func-open>`. | |
30 | ||
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31 | ``argp`` |
32 | ||
33 | ||
15e7d615 | 34 | Description |
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35 | =========== |
36 | ||
706f8a99 | 37 | .. note:: |
5377d91f | 38 | |
7347081e | 39 | This is an :ref:`obsolete` interface and may be removed |
5377d91f | 40 | in the future. It is superseded by |
af4a4d0d | 41 | :ref:`the selection API <VIDIOC_SUBDEV_G_SELECTION>`. |
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42 | |
43 | To retrieve the current crop rectangle applications set the ``pad`` | |
56683d7d | 44 | field of a struct :c:type:`v4l2_subdev_crop` to the |
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45 | desired pad number as reported by the media API and the ``which`` field |
46 | to ``V4L2_SUBDEV_FORMAT_ACTIVE``. They then call the | |
47 | ``VIDIOC_SUBDEV_G_CROP`` ioctl with a pointer to this structure. The | |
cdb4af0f | 48 | driver fills the members of the ``rect`` field or returns ``EINVAL`` error |
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49 | code if the input arguments are invalid, or if cropping is not supported |
50 | on the given pad. | |
51 | ||
52 | To change the current crop rectangle applications set both the ``pad`` | |
53 | and ``which`` fields and all members of the ``rect`` field. They then | |
54 | call the ``VIDIOC_SUBDEV_S_CROP`` ioctl with a pointer to this | |
55 | structure. The driver verifies the requested crop rectangle, adjusts it | |
56 | based on the hardware capabilities and configures the device. Upon | |
56683d7d | 57 | return the struct :c:type:`v4l2_subdev_crop` |
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58 | contains the current format as would be returned by a |
59 | ``VIDIOC_SUBDEV_G_CROP`` call. | |
60 | ||
61 | Applications can query the device capabilities by setting the ``which`` | |
62 | to ``V4L2_SUBDEV_FORMAT_TRY``. When set, 'try' crop rectangles are not | |
63 | applied to the device by the driver, but are mangled exactly as active | |
64 | crop rectangles and stored in the sub-device file handle. Two | |
65 | applications querying the same sub-device would thus not interact with | |
66 | each other. | |
67 | ||
68 | Drivers must not return an error solely because the requested crop | |
69 | rectangle doesn't match the device capabilities. They must instead | |
70 | modify the rectangle to match what the hardware can provide. The | |
71 | modified format should be as close as possible to the original request. | |
72 | ||
73 | ||
56683d7d | 74 | .. c:type:: v4l2_subdev_crop |
5377d91f | 75 | |
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76 | .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| |
77 | ||
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78 | .. flat-table:: struct v4l2_subdev_crop |
79 | :header-rows: 0 | |
80 | :stub-columns: 0 | |
81 | :widths: 1 1 2 | |
82 | ||
83 | ||
84 | - .. row 1 | |
85 | ||
86 | - __u32 | |
87 | ||
88 | - ``pad`` | |
89 | ||
90 | - Pad number as reported by the media framework. | |
91 | ||
92 | - .. row 2 | |
93 | ||
94 | - __u32 | |
95 | ||
96 | - ``which`` | |
97 | ||
98 | - Crop rectangle to get or set, from enum | |
0579e6e3 | 99 | :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. |
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100 | |
101 | - .. row 3 | |
102 | ||
e8be7e97 | 103 | - struct :c:type:`v4l2_rect` |
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104 | |
105 | - ``rect`` | |
106 | ||
107 | - Crop rectangle boundaries, in pixels. | |
108 | ||
109 | - .. row 4 | |
110 | ||
111 | - __u32 | |
112 | ||
8968da9b | 113 | - ``reserved``\ [8] |
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114 | |
115 | - Reserved for future extensions. Applications and drivers must set | |
0579e6e3 | 116 | the array to zero. |
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117 | |
118 | ||
15e7d615 | 119 | Return Value |
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120 | ============ |
121 | ||
122 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
123 | appropriately. The generic error codes are described at the | |
124 | :ref:`Generic Error Codes <gen-errors>` chapter. | |
125 | ||
126 | EBUSY | |
127 | The crop rectangle can't be changed because the pad is currently | |
128 | busy. This can be caused, for instance, by an active video stream on | |
129 | the pad. The ioctl must not be retried without performing another | |
130 | action to fix the problem first. Only returned by | |
131 | ``VIDIOC_SUBDEV_S_CROP`` | |
132 | ||
133 | EINVAL | |
56683d7d | 134 | The struct :c:type:`v4l2_subdev_crop` ``pad`` |
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135 | references a non-existing pad, the ``which`` field references a |
136 | non-existing format, or cropping is not supported on the given | |
137 | subdev pad. |