Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 EST.
1 <refentry id="vidioc-subdev-g-selection"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_SUBDEV_G_SELECTION</refname> 9 <refname>VIDIOC_SUBDEV_S_SELECTION</refname> 10 <refpurpose>Get or set selection rectangles 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_selection *<parameter>argp</parameter></paramdef> 20 </funcprototype> 21 </funcsynopsis> 22 </refsynopsisdiv> 23 24 <refsect1> 25 <title>Arguments</title> 26 27 <variablelist> 28 <varlistentry> 29 <term><parameter>fd</parameter></term> 30 <listitem> 31 <para>&fd;</para> 32 </listitem> 33 </varlistentry> 34 <varlistentry> 35 <term><parameter>request</parameter></term> 36 <listitem> 37 <para>VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION</para> 38 </listitem> 39 </varlistentry> 40 <varlistentry> 41 <term><parameter>argp</parameter></term> 42 <listitem> 43 <para></para> 44 </listitem> 45 </varlistentry> 46 </variablelist> 47 </refsect1> 48 49 <refsect1> 50 <title>Description</title> 51 52 <para>The selections are used to configure various image 53 processing functionality performed by the subdevs which affect the 54 image size. This currently includes cropping, scaling and 55 composition.</para> 56 57 <para>The selection API replaces <link 58 linkend="vidioc-subdev-g-crop">the old subdev crop API</link>. All 59 the function of the crop API, and more, are supported by the 60 selections API.</para> 61 62 <para>See <xref linkend="subdev"></xref> for 63 more information on how each selection target affects the image 64 processing pipeline inside the subdevice.</para> 65 66 <refsect2> 67 <title>Types of selection targets</title> 68 69 <para>There are two types of selection targets: actual and bounds. The 70 actual targets are the targets which configure the hardware. The BOUNDS 71 target will return a rectangle that contain all possible actual 72 rectangles.</para> 73 </refsect2> 74 75 <refsect2> 76 <title>Discovering supported features</title> 77 78 <para>To discover which targets are supported, the user can 79 perform <constant>VIDIOC_SUBDEV_G_SELECTION</constant> on them. 80 Any unsupported target will return 81 <constant>EINVAL</constant>.</para> 82 83 <para>Selection targets and flags are documented in <xref 84 linkend="v4l2-selections-common"/>.</para> 85 86 <table pgwide="1" frame="none" id="v4l2-subdev-selection"> 87 <title>struct <structname>v4l2_subdev_selection</structname></title> 88 <tgroup cols="3"> 89 &cs-str; 90 <tbody valign="top"> 91 <row> 92 <entry>__u32</entry> 93 <entry><structfield>which</structfield></entry> 94 <entry>Active or try selection, from 95 &v4l2-subdev-format-whence;.</entry> 96 </row> 97 <row> 98 <entry>__u32</entry> 99 <entry><structfield>pad</structfield></entry> 100 <entry>Pad number as reported by the media framework.</entry> 101 </row> 102 <row> 103 <entry>__u32</entry> 104 <entry><structfield>target</structfield></entry> 105 <entry>Target selection rectangle. See 106 <xref linkend="v4l2-selections-common" />.</entry> 107 </row> 108 <row> 109 <entry>__u32</entry> 110 <entry><structfield>flags</structfield></entry> 111 <entry>Flags. See 112 <xref linkend="v4l2-selection-flags" />.</entry> 113 </row> 114 <row> 115 <entry>&v4l2-rect;</entry> 116 <entry><structfield>r</structfield></entry> 117 <entry>Selection rectangle, in pixels.</entry> 118 </row> 119 <row> 120 <entry>__u32</entry> 121 <entry><structfield>reserved</structfield>[8]</entry> 122 <entry>Reserved for future extensions. Applications and drivers must 123 set the array to zero.</entry> 124 </row> 125 </tbody> 126 </tgroup> 127 </table> 128 </refsect2> 129 130 </refsect1> 131 132 <refsect1> 133 &return-value; 134 135 <variablelist> 136 <varlistentry> 137 <term><errorcode>EBUSY</errorcode></term> 138 <listitem> 139 <para>The selection rectangle can't be changed because the 140 pad is currently busy. This can be caused, for instance, by 141 an active video stream on the pad. The ioctl must not be 142 retried without performing another action to fix the problem 143 first. Only returned by 144 <constant>VIDIOC_SUBDEV_S_SELECTION</constant></para> 145 </listitem> 146 </varlistentry> 147 <varlistentry> 148 <term><errorcode>EINVAL</errorcode></term> 149 <listitem> 150 <para>The &v4l2-subdev-selection; 151 <structfield>pad</structfield> references a non-existing 152 pad, the <structfield>which</structfield> field references a 153 non-existing format, or the selection target is not 154 supported on the given subdev pad.</para> 155 </listitem> 156 </varlistentry> 157 </variablelist> 158 </refsect1> 159 </refentry>
