Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 EST.
1 <refentry id="vidioc-subdev-g-crop"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_SUBDEV_G_CROP</refname> 9 <refname>VIDIOC_SUBDEV_S_CROP</refname> 10 <refpurpose>Get or set the crop rectangle on a subdev pad</refpurpose> 11 </refnamediv> 12 13 <refsynopsisdiv> 14 <funcsynopsis> 15 <funcprototype> 16 <funcdef>int <function>ioctl</function></funcdef> 17 <paramdef>int <parameter>fd</parameter></paramdef> 18 <paramdef>int <parameter>request</parameter></paramdef> 19 <paramdef>struct v4l2_subdev_crop *<parameter>argp</parameter></paramdef> 20 </funcprototype> 21 </funcsynopsis> 22 <funcsynopsis> 23 <funcprototype> 24 <funcdef>int <function>ioctl</function></funcdef> 25 <paramdef>int <parameter>fd</parameter></paramdef> 26 <paramdef>int <parameter>request</parameter></paramdef> 27 <paramdef>const struct v4l2_subdev_crop *<parameter>argp</parameter></paramdef> 28 </funcprototype> 29 </funcsynopsis> 30 </refsynopsisdiv> 31 32 <refsect1> 33 <title>Arguments</title> 34 35 <variablelist> 36 <varlistentry> 37 <term><parameter>fd</parameter></term> 38 <listitem> 39 <para>&fd;</para> 40 </listitem> 41 </varlistentry> 42 <varlistentry> 43 <term><parameter>request</parameter></term> 44 <listitem> 45 <para>VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP</para> 46 </listitem> 47 </varlistentry> 48 <varlistentry> 49 <term><parameter>argp</parameter></term> 50 <listitem> 51 <para></para> 52 </listitem> 53 </varlistentry> 54 </variablelist> 55 </refsect1> 56 57 <refsect1> 58 <title>Description</title> 59 60 <note> 61 <title>Obsolete</title> 62 63 <para>This is an <link linkend="obsolete">obsolete</link> 64 interface and may be removed in the future. It is superseded by 65 <link linkend="vidioc-subdev-g-selection">the selection 66 API</link>.</para> 67 </note> 68 69 <para>To retrieve the current crop rectangle applications set the 70 <structfield>pad</structfield> field of a &v4l2-subdev-crop; to the 71 desired pad number as reported by the media API and the 72 <structfield>which</structfield> field to 73 <constant>V4L2_SUBDEV_FORMAT_ACTIVE</constant>. They then call the 74 <constant>VIDIOC_SUBDEV_G_CROP</constant> ioctl with a pointer to this 75 structure. The driver fills the members of the <structfield>rect</structfield> 76 field or returns &EINVAL; if the input arguments are invalid, or if cropping 77 is not supported on the given pad.</para> 78 79 <para>To change the current crop rectangle applications set both the 80 <structfield>pad</structfield> and <structfield>which</structfield> fields 81 and all members of the <structfield>rect</structfield> field. They then call 82 the <constant>VIDIOC_SUBDEV_S_CROP</constant> ioctl with a pointer to this 83 structure. The driver verifies the requested crop rectangle, adjusts it 84 based on the hardware capabilities and configures the device. Upon return 85 the &v4l2-subdev-crop; contains the current format as would be returned 86 by a <constant>VIDIOC_SUBDEV_G_CROP</constant> call.</para> 87 88 <para>Applications can query the device capabilities by setting the 89 <structfield>which</structfield> to 90 <constant>V4L2_SUBDEV_FORMAT_TRY</constant>. When set, 'try' crop 91 rectangles are not applied to the device by the driver, but are mangled 92 exactly as active crop rectangles and stored in the sub-device file handle. 93 Two applications querying the same sub-device would thus not interact with 94 each other.</para> 95 96 <para>Drivers must not return an error solely because the requested crop 97 rectangle doesn't match the device capabilities. They must instead modify 98 the rectangle to match what the hardware can provide. The modified format 99 should be as close as possible to the original request.</para> 100 101 <table pgwide="1" frame="none" id="v4l2-subdev-crop"> 102 <title>struct <structname>v4l2_subdev_crop</structname></title> 103 <tgroup cols="3"> 104 &cs-str; 105 <tbody valign="top"> 106 <row> 107 <entry>__u32</entry> 108 <entry><structfield>pad</structfield></entry> 109 <entry>Pad number as reported by the media framework.</entry> 110 </row> 111 <row> 112 <entry>__u32</entry> 113 <entry><structfield>which</structfield></entry> 114 <entry>Crop rectangle to get or set, from 115 &v4l2-subdev-format-whence;.</entry> 116 </row> 117 <row> 118 <entry>&v4l2-rect;</entry> 119 <entry><structfield>rect</structfield></entry> 120 <entry>Crop rectangle boundaries, in pixels.</entry> 121 </row> 122 <row> 123 <entry>__u32</entry> 124 <entry><structfield>reserved</structfield>[8]</entry> 125 <entry>Reserved for future extensions. Applications and drivers must 126 set the array to zero.</entry> 127 </row> 128 </tbody> 129 </tgroup> 130 </table> 131 </refsect1> 132 133 <refsect1> 134 &return-value; 135 136 <variablelist> 137 <varlistentry> 138 <term><errorcode>EBUSY</errorcode></term> 139 <listitem> 140 <para>The crop rectangle can't be changed because the pad is currently 141 busy. This can be caused, for instance, by an active video stream on 142 the pad. The ioctl must not be retried without performing another 143 action to fix the problem first. Only returned by 144 <constant>VIDIOC_SUBDEV_S_CROP</constant></para> 145 </listitem> 146 </varlistentry> 147 <varlistentry> 148 <term><errorcode>EINVAL</errorcode></term> 149 <listitem> 150 <para>The &v4l2-subdev-crop; <structfield>pad</structfield> 151 references a non-existing pad, the <structfield>which</structfield> 152 field references a non-existing format, or cropping is not supported 153 on the given subdev pad.</para> 154 </listitem> 155 </varlistentry> 156 </variablelist> 157 </refsect1> 158 </refentry>
