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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-g-selection.xml')
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1 files changed, 0 insertions, 239 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-g-selection.xml b/Documentation/DocBook/media/v4l/vidioc-g-selection.xml deleted file mode 100644 index 7865351688da..000000000000 --- a/Documentation/DocBook/media/v4l/vidioc-g-selection.xml +++ /dev/null @@ -1,239 +0,0 @@ -<refentry id="vidioc-g-selection"> - - <refmeta> - <refentrytitle>ioctl VIDIOC_G_SELECTION, VIDIOC_S_SELECTION</refentrytitle> - &manvol; - </refmeta> - - <refnamediv> - <refname>VIDIOC_G_SELECTION</refname> - <refname>VIDIOC_S_SELECTION</refname> - <refpurpose>Get or set one of the selection rectangles</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_selection *<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_G_SELECTION, VIDIOC_S_SELECTION</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>The ioctls are used to query and configure selection rectangles.</para> - -<para>To query the cropping (composing) rectangle set &v4l2-selection; -<structfield> type </structfield> field to the respective buffer type. -Do not use the multiplanar buffer types. Use <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> -instead of <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant> and use -<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> instead of -<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>. The next step is -setting the value of &v4l2-selection; <structfield>target</structfield> field -to <constant>V4L2_SEL_TGT_CROP</constant> (<constant>V4L2_SEL_TGT_COMPOSE</constant>). -Please refer to table <xref linkend="v4l2-selections-common" /> or <xref linkend="selection-api" /> -for additional targets. The <structfield>flags</structfield> and <structfield>reserved -</structfield> fields of &v4l2-selection; are ignored and they must be filled -with zeros. The driver fills the rest of the structure or -returns &EINVAL; if incorrect buffer type or target was used. If cropping -(composing) is not supported then the active rectangle is not mutable and it is -always equal to the bounds rectangle. Finally, the &v4l2-rect; -<structfield>r</structfield> rectangle is filled with the current cropping -(composing) coordinates. The coordinates are expressed in driver-dependent -units. The only exception are rectangles for images in raw formats, whose -coordinates are always expressed in pixels.</para> - -<para>To change the cropping (composing) rectangle set the &v4l2-selection; -<structfield>type</structfield> field to the respective buffer type. Do not -use multiplanar buffers. Use <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> -instead of <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant>. Use -<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> instead of -<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>. The next step is -setting the value of &v4l2-selection; <structfield>target</structfield> to -<constant>V4L2_SEL_TGT_CROP</constant> (<constant>V4L2_SEL_TGT_COMPOSE</constant>). -Please refer to table <xref linkend="v4l2-selections-common" /> or <xref linkend="selection-api" /> -for additional targets. The &v4l2-rect; <structfield>r</structfield> rectangle need to be -set to the desired active area. Field &v4l2-selection; <structfield> reserved -</structfield> is ignored and must be filled with zeros. The driver may adjust -coordinates of the requested rectangle. An application may -introduce constraints to control rounding behaviour. The &v4l2-selection; -<structfield>flags</structfield> field must be set to one of the following: - -<itemizedlist> - <listitem> -<para><constant>0</constant> - The driver can adjust the rectangle size freely -and shall choose a crop/compose rectangle as close as possible to the requested -one.</para> - </listitem> - <listitem> -<para><constant>V4L2_SEL_FLAG_GE</constant> - The driver is not allowed to -shrink the rectangle. The original rectangle must lay inside the adjusted -one.</para> - </listitem> - <listitem> -<para><constant>V4L2_SEL_FLAG_LE</constant> - The driver is not allowed to -enlarge the rectangle. The adjusted rectangle must lay inside the original -one.</para> - </listitem> - <listitem> -<para><constant>V4L2_SEL_FLAG_GE | V4L2_SEL_FLAG_LE</constant> - The driver -must choose the size exactly the same as in the requested rectangle.</para> - </listitem> -</itemizedlist> - -Please refer to <xref linkend="sel-const-adjust" />. - -</para> - -<para> The driver may have to adjusts the requested dimensions against hardware -limits and other parts as the pipeline, i.e. the bounds given by the -capture/output window or TV display. The closest possible values of horizontal -and vertical offset and sizes are chosen according to following priority: - -<orderedlist> - <listitem> - <para>Satisfy constraints from &v4l2-selection; <structfield>flags</structfield>.</para> - </listitem> - <listitem> - <para>Adjust width, height, left, and top to hardware limits and alignments.</para> - </listitem> - <listitem> - <para>Keep center of adjusted rectangle as close as possible to the original one.</para> - </listitem> - <listitem> - <para>Keep width and height as close as possible to original ones.</para> - </listitem> - <listitem> - <para>Keep horizontal and vertical offset as close as possible to original ones.</para> - </listitem> -</orderedlist> - -On success the &v4l2-rect; <structfield>r</structfield> field contains -the adjusted rectangle. When the parameters are unsuitable the application may -modify the cropping (composing) or image parameters and repeat the cycle until -satisfactory parameters have been negotiated. If constraints flags have to be -violated at then ERANGE is returned. The error indicates that <emphasis>there -exist no rectangle</emphasis> that satisfies the constraints.</para> - - <para>Selection targets and flags are documented in <xref - linkend="v4l2-selections-common"/>.</para> - - <para> - <figure id="sel-const-adjust"> - <title>Size adjustments with constraint flags.</title> - <mediaobject> - <imageobject> - <imagedata fileref="constraints.png" format="PNG" /> - </imageobject> - <textobject> - <phrase>Behaviour of rectangle adjustment for different constraint - flags.</phrase> - </textobject> - </mediaobject> - </figure> - </para> - - <para> - <table pgwide="1" frame="none" id="v4l2-selection"> - <title>struct <structname>v4l2_selection</structname></title> - <tgroup cols="3"> - &cs-str; - <tbody valign="top"> - <row> - <entry>__u32</entry> - <entry><structfield>type</structfield></entry> - <entry>Type of the buffer (from &v4l2-buf-type;).</entry> - </row> - <row> - <entry>__u32</entry> - <entry><structfield>target</structfield></entry> - <entry>Used to select between <link linkend="v4l2-selections-common"> cropping - and composing rectangles</link>.</entry> - </row> - <row> - <entry>__u32</entry> - <entry><structfield>flags</structfield></entry> - <entry>Flags controlling the selection rectangle adjustments, refer to - <link linkend="v4l2-selection-flags">selection flags</link>.</entry> - </row> - <row> - <entry>&v4l2-rect;</entry> - <entry><structfield>r</structfield></entry> - <entry>The selection rectangle.</entry> - </row> - <row> - <entry>__u32</entry> - <entry><structfield>reserved[9]</structfield></entry> - <entry>Reserved fields for future use. Drivers and applications must zero this array.</entry> - </row> - </tbody> - </tgroup> - </table> - </para> - </refsect1> - - <refsect1> - &return-value; - <variablelist> - <varlistentry> - <term><errorcode>EINVAL</errorcode></term> - <listitem> - <para>Given buffer type <structfield>type</structfield> or -the selection target <structfield>target</structfield> is not supported, -or the <structfield>flags</structfield> argument is not valid.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><errorcode>ERANGE</errorcode></term> - <listitem> - <para>It is not possible to adjust &v4l2-rect; <structfield> -r</structfield> rectangle to satisfy all contraints given in the -<structfield>flags</structfield> argument.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><errorcode>EBUSY</errorcode></term> - <listitem> - <para>It is not possible to apply change of the selection rectangle -at the moment. Usually because streaming is in progress.</para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> - -</refentry> |