+++ /dev/null
-<refentry id="vidioc-subdev-g-crop">
- <refmeta>
- <refentrytitle>ioctl VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP</refentrytitle>
- &manvol;
- </refmeta>
-
- <refnamediv>
- <refname>VIDIOC_SUBDEV_G_CROP</refname>
- <refname>VIDIOC_SUBDEV_S_CROP</refname>
- <refpurpose>Get or set the crop rectangle on a subdev pad</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcprototype>
- <funcdef>int <function>ioctl</function></funcdef>
- <paramdef>int <parameter>fd</parameter></paramdef>
- <paramdef>int <parameter>request</parameter></paramdef>
- <paramdef>struct v4l2_subdev_crop *<parameter>argp</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- <funcsynopsis>
- <funcprototype>
- <funcdef>int <function>ioctl</function></funcdef>
- <paramdef>int <parameter>fd</parameter></paramdef>
- <paramdef>int <parameter>request</parameter></paramdef>
- <paramdef>const struct v4l2_subdev_crop *<parameter>argp</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- </refsynopsisdiv>
-
- <refsect1>
- <title>Arguments</title>
-
- <variablelist>
- <varlistentry>
- <term><parameter>fd</parameter></term>
- <listitem>
- <para>&fd;</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><parameter>request</parameter></term>
- <listitem>
- <para>VIDIOC_SUBDEV_G_CROP, VIDIOC_SUBDEV_S_CROP</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><parameter>argp</parameter></term>
- <listitem>
- <para></para>
- </listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
-
- <refsect1>
- <title>Description</title>
-
- <note>
- <title>Experimental</title>
- <para>This is an <link linkend="experimental">experimental</link>
- interface and may change in the future.</para>
- </note>
-
- <para>To retrieve the current crop rectangle applications set the
- <structfield>pad</structfield> field of a &v4l2-subdev-crop; to the
- desired pad number as reported by the media API and the
- <structfield>which</structfield> field to
- <constant>V4L2_SUBDEV_FORMAT_ACTIVE</constant>. They then call the
- <constant>VIDIOC_SUBDEV_G_CROP</constant> ioctl with a pointer to this
- structure. The driver fills the members of the <structfield>rect</structfield>
- field or returns &EINVAL; if the input arguments are invalid, or if cropping
- is not supported on the given pad.</para>
-
- <para>To change the current crop rectangle applications set both the
- <structfield>pad</structfield> and <structfield>which</structfield> fields
- and all members of the <structfield>rect</structfield> field. They then call
- the <constant>VIDIOC_SUBDEV_S_CROP</constant> ioctl with a pointer to this
- structure. The driver verifies the requested crop rectangle, adjusts it
- based on the hardware capabilities and configures the device. Upon return
- the &v4l2-subdev-crop; contains the current format as would be returned
- by a <constant>VIDIOC_SUBDEV_G_CROP</constant> call.</para>
-
- <para>Applications can query the device capabilities by setting the
- <structfield>which</structfield> to
- <constant>V4L2_SUBDEV_FORMAT_TRY</constant>. When set, 'try' crop
- rectangles are not applied to the device by the driver, but are mangled
- exactly as active crop rectangles and stored in the sub-device file handle.
- Two applications querying the same sub-device would thus not interact with
- each other.</para>
-
- <para>Drivers must not return an error solely because the requested crop
- rectangle doesn't match the device capabilities. They must instead modify
- the rectangle to match what the hardware can provide. The modified format
- should be as close as possible to the original request.</para>
-
- <table pgwide="1" frame="none" id="v4l2-subdev-crop">
- <title>struct <structname>v4l2_subdev_crop</structname></title>
- <tgroup cols="3">
- &cs-str;
- <tbody valign="top">
- <row>
- <entry>__u32</entry>
- <entry><structfield>pad</structfield></entry>
- <entry>Pad number as reported by the media framework.</entry>
- </row>
- <row>
- <entry>__u32</entry>
- <entry><structfield>which</structfield></entry>
- <entry>Crop rectangle to get or set, from
- &v4l2-subdev-format-whence;.</entry>
- </row>
- <row>
- <entry>&v4l2-rect;</entry>
- <entry><structfield>rect</structfield></entry>
- <entry>Crop rectangle boundaries, in pixels.</entry>
- </row>
- <row>
- <entry>__u32</entry>
- <entry><structfield>reserved</structfield>[8]</entry>
- <entry>Reserved for future extensions. Applications and drivers must
- set the array to zero.</entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </refsect1>
-
- <refsect1>
- &return-value;
-
- <variablelist>
- <varlistentry>
- <term><errorcode>EBUSY</errorcode></term>
- <listitem>
- <para>The crop rectangle can't be changed because the pad is currently
- busy. This can be caused, for instance, by an active video stream on
- the pad. The ioctl must not be retried without performing another
- action to fix the problem first. Only returned by
- <constant>VIDIOC_SUBDEV_S_CROP</constant></para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><errorcode>EINVAL</errorcode></term>
- <listitem>
- <para>The &v4l2-subdev-crop; <structfield>pad</structfield>
- references a non-existing pad, the <structfield>which</structfield>
- field references a non-existing format, or cropping is not supported
- on the given subdev pad.</para>
- </listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
-</refentry>
git.openpandora.org / pandora-kernel.git / blobdiff