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- <section id="v4l2-selections-common">
- <title>Common selection definitions</title>
- <para>While the <link linkend="selection-api">V4L2 selection
- API</link> and <link linkend="v4l2-subdev-selections">V4L2 subdev
- selection APIs</link> are very similar, there's one fundamental
- difference between the two. On sub-device API, the selection
- rectangle refers to the media bus format, and is bound to a
- sub-device's pad. On the V4L2 interface the selection rectangles
- refer to the in-memory pixel format.</para>
- <para>This section defines the common definitions of the
- selection interfaces on the two APIs.</para>
- <section id="v4l2-selection-targets">
- <title>Selection targets</title>
- <para>The precise meaning of the selection targets may be
- dependent on which of the two interfaces they are used.</para>
- <table pgwide="1" frame="none" id="v4l2-selection-targets-table">
- <title>Selection target definitions</title>
- <tgroup cols="5">
- <colspec colname="c1" />
- <colspec colname="c2" />
- <colspec colname="c3" />
- <colspec colname="c4" />
- <colspec colname="c5" />
- &cs-def;
- <thead>
- <row rowsep="1">
- <entry align="left">Target name</entry>
- <entry align="left">id</entry>
- <entry align="left">Definition</entry>
- <entry align="left">Valid for V4L2</entry>
- <entry align="left">Valid for V4L2 subdev</entry>
- </row>
- </thead>
- <tbody valign="top">
- <row>
- <entry><constant>V4L2_SEL_TGT_CROP</constant></entry>
- <entry>0x0000</entry>
- <entry>Crop rectangle. Defines the cropped area.</entry>
- <entry>Yes</entry>
- <entry>Yes</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_TGT_CROP_DEFAULT</constant></entry>
- <entry>0x0001</entry>
- <entry>Suggested cropping rectangle that covers the "whole picture".</entry>
- <entry>Yes</entry>
- <entry>No</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_TGT_CROP_BOUNDS</constant></entry>
- <entry>0x0002</entry>
- <entry>Bounds of the crop rectangle. All valid crop
- rectangles fit inside the crop bounds rectangle.
- </entry>
- <entry>Yes</entry>
- <entry>Yes</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_TGT_NATIVE_SIZE</constant></entry>
- <entry>0x0003</entry>
- <entry>The native size of the device, e.g. a sensor's
- pixel array. <structfield>left</structfield> and
- <structfield>top</structfield> fields are zero for this
- target. Setting the native size will generally only make
- sense for memory to memory devices where the software can
- create a canvas of a given size in which for example a
- video frame can be composed. In that case
- V4L2_SEL_TGT_NATIVE_SIZE can be used to configure the size
- of that canvas.
- </entry>
- <entry>Yes</entry>
- <entry>Yes</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_TGT_COMPOSE</constant></entry>
- <entry>0x0100</entry>
- <entry>Compose rectangle. Used to configure scaling
- and composition.</entry>
- <entry>Yes</entry>
- <entry>Yes</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_TGT_COMPOSE_DEFAULT</constant></entry>
- <entry>0x0101</entry>
- <entry>Suggested composition rectangle that covers the "whole picture".</entry>
- <entry>Yes</entry>
- <entry>No</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_TGT_COMPOSE_BOUNDS</constant></entry>
- <entry>0x0102</entry>
- <entry>Bounds of the compose rectangle. All valid compose
- rectangles fit inside the compose bounds rectangle.</entry>
- <entry>Yes</entry>
- <entry>Yes</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_TGT_COMPOSE_PADDED</constant></entry>
- <entry>0x0103</entry>
- <entry>The active area and all padding pixels that are inserted or
- modified by hardware.</entry>
- <entry>Yes</entry>
- <entry>No</entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </section>
- <section id="v4l2-selection-flags">
- <title>Selection flags</title>
- <table pgwide="1" frame="none" id="v4l2-selection-flags-table">
- <title>Selection flag definitions</title>
- <tgroup cols="5">
- <colspec colname="c1" />
- <colspec colname="c2" />
- <colspec colname="c3" />
- <colspec colname="c4" />
- <colspec colname="c5" />
- &cs-def;
- <thead>
- <row rowsep="1">
- <entry align="left">Flag name</entry>
- <entry align="left">id</entry>
- <entry align="left">Definition</entry>
- <entry align="left">Valid for V4L2</entry>
- <entry align="left">Valid for V4L2 subdev</entry>
- </row>
- </thead>
- <tbody valign="top">
- <row>
- <entry><constant>V4L2_SEL_FLAG_GE</constant></entry>
- <entry>(1 << 0)</entry>
- <entry>Suggest the driver it should choose greater or
- equal rectangle (in size) than was requested. Albeit the
- driver may choose a lesser size, it will only do so due to
- hardware limitations. Without this flag (and
- <constant>V4L2_SEL_FLAG_LE</constant>) the
- behaviour is to choose the closest possible
- rectangle.</entry>
- <entry>Yes</entry>
- <entry>Yes</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_FLAG_LE</constant></entry>
- <entry>(1 << 1)</entry>
- <entry>Suggest the driver it
- should choose lesser or equal rectangle (in size) than was
- requested. Albeit the driver may choose a greater size, it
- will only do so due to hardware limitations.</entry>
- <entry>Yes</entry>
- <entry>Yes</entry>
- </row>
- <row>
- <entry><constant>V4L2_SEL_FLAG_KEEP_CONFIG</constant></entry>
- <entry>(1 << 2)</entry>
- <entry>The configuration must not be propagated to any
- further processing steps. If this flag is not given, the
- configuration is propagated inside the subdevice to all
- further processing steps.</entry>
- <entry>No</entry>
- <entry>Yes</entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </section>
- </section>
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