<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_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>