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Based on kernel version 3.9. Page generated on 2013-05-02 23:04 EST.

1	<section id="v4l2-selections-common">
2	
3	  <title>Common selection definitions</title>
4	
5	  <para>While the <link linkend="selection-api">V4L2 selection
6	  API</link> and <link linkend="v4l2-subdev-selections">V4L2 subdev
7	  selection APIs</link> are very similar, there's one fundamental
8	  difference between the two. On sub-device API, the selection
9	  rectangle refers to the media bus format, and is bound to a
10	  sub-device's pad. On the V4L2 interface the selection rectangles
11	  refer to the in-memory pixel format.</para>
12	
13	  <para>This section defines the common definitions of the
14	  selection interfaces on the two APIs.</para>
15	
16	  <section id="v4l2-selection-targets">
17	
18	    <title>Selection targets</title>
19	
20	    <para>The precise meaning of the selection targets may be
21	    dependent on which of the two interfaces they are used.</para>
22	
23	    <table pgwide="1" frame="none" id="v4l2-selection-targets-table">
24	    <title>Selection target definitions</title>
25	      <tgroup cols="5">
26		<colspec colname="c1" />
27		<colspec colname="c2" />
28		<colspec colname="c3" />
29		<colspec colname="c4" />
30		<colspec colname="c5" />
31		&cs-def;
32		<thead>
33		  <row rowsep="1">
34		    <entry align="left">Target name</entry>
35		    <entry align="left">id</entry>
36		    <entry align="left">Definition</entry>
37		    <entry align="left">Valid for V4L2</entry>
38		    <entry align="left">Valid for V4L2 subdev</entry>
39		  </row>
40		</thead>
41		<tbody valign="top">
42		  <row>
43		    <entry><constant>V4L2_SEL_TGT_CROP</constant></entry>
44		    <entry>0x0000</entry>
45		    <entry>Crop rectangle. Defines the cropped area.</entry>
46		    <entry>Yes</entry>
47		    <entry>Yes</entry>
48		  </row>
49		  <row>
50		    <entry><constant>V4L2_SEL_TGT_CROP_DEFAULT</constant></entry>
51		    <entry>0x0001</entry>
52		    <entry>Suggested cropping rectangle that covers the "whole picture".</entry>
53		    <entry>Yes</entry>
54		    <entry>No</entry>
55		  </row>
56		  <row>
57		    <entry><constant>V4L2_SEL_TGT_CROP_BOUNDS</constant></entry>
58		    <entry>0x0002</entry>
59		    <entry>Bounds of the crop rectangle. All valid crop
60		    rectangles fit inside the crop bounds rectangle.
61		    </entry>
62		    <entry>Yes</entry>
63		    <entry>Yes</entry>
64		  </row>
65		  <row>
66		    <entry><constant>V4L2_SEL_TGT_COMPOSE</constant></entry>
67		    <entry>0x0100</entry>
68		    <entry>Compose rectangle. Used to configure scaling
69		    and composition.</entry>
70		    <entry>Yes</entry>
71		    <entry>Yes</entry>
72		  </row>
73		  <row>
74		    <entry><constant>V4L2_SEL_TGT_COMPOSE_DEFAULT</constant></entry>
75		    <entry>0x0101</entry>
76		    <entry>Suggested composition rectangle that covers the "whole picture".</entry>
77		    <entry>Yes</entry>
78		    <entry>No</entry>
79		  </row>
80		  <row>
81		    <entry><constant>V4L2_SEL_TGT_COMPOSE_BOUNDS</constant></entry>
82		    <entry>0x0102</entry>
83		    <entry>Bounds of the compose rectangle. All valid compose
84		    rectangles fit inside the compose bounds rectangle.</entry>
85		    <entry>Yes</entry>
86		    <entry>Yes</entry>
87		  </row>
88		  <row>
89		    <entry><constant>V4L2_SEL_TGT_COMPOSE_PADDED</constant></entry>
90		    <entry>0x0103</entry>
91		    <entry>The active area and all padding pixels that are inserted or
92		    modified by hardware.</entry>
93		    <entry>Yes</entry>
94		    <entry>No</entry>
95		  </row>
96		</tbody>
97	      </tgroup>
98	    </table>
99	
100	  </section>
101	
102	  <section id="v4l2-selection-flags">
103	
104	    <title>Selection flags</title>
105	
106	    <table pgwide="1" frame="none" id="v4l2-selection-flags-table">
107	    <title>Selection flag definitions</title>
108	      <tgroup cols="5">
109		<colspec colname="c1" />
110		<colspec colname="c2" />
111		<colspec colname="c3" />
112		<colspec colname="c4" />
113		<colspec colname="c5" />
114		&cs-def;
115		<thead>
116		<row rowsep="1">
117		    <entry align="left">Flag name</entry>
118		    <entry align="left">id</entry>
119		    <entry align="left">Definition</entry>
120		    <entry align="left">Valid for V4L2</entry>
121		    <entry align="left">Valid for V4L2 subdev</entry>
122		</row>
123		</thead>
124		<tbody valign="top">
125		  <row>
126		    <entry><constant>V4L2_SEL_FLAG_GE</constant></entry>
127		    <entry>(1 &lt;&lt; 0)</entry>
128		    <entry>Suggest the driver it should choose greater or
129		    equal rectangle (in size) than was requested. Albeit the
130		    driver may choose a lesser size, it will only do so due to
131		    hardware limitations. Without this flag (and
132		    <constant>V4L2_SEL_FLAG_LE</constant>) the
133		    behaviour is to choose the closest possible
134		    rectangle.</entry>
135		    <entry>Yes</entry>
136		    <entry>Yes</entry>
137		  </row>
138		  <row>
139		    <entry><constant>V4L2_SEL_FLAG_LE</constant></entry>
140		    <entry>(1 &lt;&lt; 1)</entry>
141		    <entry>Suggest the driver it
142		    should choose lesser or equal rectangle (in size) than was
143		    requested. Albeit the driver may choose a greater size, it
144		    will only do so due to hardware limitations.</entry>
145		    <entry>Yes</entry>
146		    <entry>Yes</entry>
147		  </row>
148		  <row>
149		    <entry><constant>V4L2_SEL_FLAG_KEEP_CONFIG</constant></entry>
150		    <entry>(1 &lt;&lt; 2)</entry>
151		    <entry>The configuration must not be propagated to any
152		    further processing steps. If this flag is not given, the
153		    configuration is propagated inside the subdevice to all
154		    further processing steps.</entry>
155		    <entry>No</entry>
156		    <entry>Yes</entry>
157		  </row>
158		</tbody>
159	      </tgroup>
160	    </table>
161	
162	  </section>
163	
164	</section>
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