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author | Anton Vorontsov <avorontsov@ru.mvista.com> | 2009-09-22 19:49:27 -0400 |
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committer | Anton Vorontsov <avorontsov@ru.mvista.com> | 2009-09-22 19:49:27 -0400 |
commit | f056878332a91ed984a116bad4e7d49aefff9e6e (patch) | |
tree | 572f4757c8e7811d45e0be0c2ae529c78fb63441 /Documentation/DocBook/v4l/vidioc-cropcap.xml | |
parent | 3961f7c3cf247eee5df7fabadc7a40f2deeb98f3 (diff) | |
parent | 7fa07729e439a6184bd824746d06a49cca553f15 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
drivers/power/wm97xx_battery.c
Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-cropcap.xml')
-rw-r--r-- | Documentation/DocBook/v4l/vidioc-cropcap.xml | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/Documentation/DocBook/v4l/vidioc-cropcap.xml b/Documentation/DocBook/v4l/vidioc-cropcap.xml new file mode 100644 index 000000000000..816e90e283c5 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-cropcap.xml | |||
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1 | <refentry id="vidioc-cropcap"> | ||
2 | <refmeta> | ||
3 | <refentrytitle>ioctl VIDIOC_CROPCAP</refentrytitle> | ||
4 | &manvol; | ||
5 | </refmeta> | ||
6 | |||
7 | <refnamediv> | ||
8 | <refname>VIDIOC_CROPCAP</refname> | ||
9 | <refpurpose>Information about the video cropping and scaling abilities</refpurpose> | ||
10 | </refnamediv> | ||
11 | |||
12 | <refsynopsisdiv> | ||
13 | <funcsynopsis> | ||
14 | <funcprototype> | ||
15 | <funcdef>int <function>ioctl</function></funcdef> | ||
16 | <paramdef>int <parameter>fd</parameter></paramdef> | ||
17 | <paramdef>int <parameter>request</parameter></paramdef> | ||
18 | <paramdef>struct v4l2_cropcap | ||
19 | *<parameter>argp</parameter></paramdef> | ||
20 | </funcprototype> | ||
21 | </funcsynopsis> | ||
22 | </refsynopsisdiv> | ||
23 | |||
24 | <refsect1> | ||
25 | <title>Arguments</title> | ||
26 | |||
27 | <variablelist> | ||
28 | <varlistentry> | ||
29 | <term><parameter>fd</parameter></term> | ||
30 | <listitem> | ||
31 | <para>&fd;</para> | ||
32 | </listitem> | ||
33 | </varlistentry> | ||
34 | <varlistentry> | ||
35 | <term><parameter>request</parameter></term> | ||
36 | <listitem> | ||
37 | <para>VIDIOC_CROPCAP</para> | ||
38 | </listitem> | ||
39 | </varlistentry> | ||
40 | <varlistentry> | ||
41 | <term><parameter>argp</parameter></term> | ||
42 | <listitem> | ||
43 | <para></para> | ||
44 | </listitem> | ||
45 | </varlistentry> | ||
46 | </variablelist> | ||
47 | </refsect1> | ||
48 | |||
49 | <refsect1> | ||
50 | <title>Description</title> | ||
51 | |||
52 | <para>Applications use this function to query the cropping | ||
53 | limits, the pixel aspect of images and to calculate scale factors. | ||
54 | They set the <structfield>type</structfield> field of a v4l2_cropcap | ||
55 | structure to the respective buffer (stream) type and call the | ||
56 | <constant>VIDIOC_CROPCAP</constant> ioctl with a pointer to this | ||
57 | structure. Drivers fill the rest of the structure. The results are | ||
58 | constant except when switching the video standard. Remember this | ||
59 | switch can occur implicit when switching the video input or | ||
60 | output.</para> | ||
61 | |||
62 | <table pgwide="1" frame="none" id="v4l2-cropcap"> | ||
63 | <title>struct <structname>v4l2_cropcap</structname></title> | ||
64 | <tgroup cols="3"> | ||
65 | &cs-str; | ||
66 | <tbody valign="top"> | ||
67 | <row> | ||
68 | <entry>&v4l2-buf-type;</entry> | ||
69 | <entry><structfield>type</structfield></entry> | ||
70 | <entry>Type of the data stream, set by the application. | ||
71 | Only these types are valid here: | ||
72 | <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>, | ||
73 | <constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, | ||
74 | <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver | ||
75 | defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant> | ||
76 | and higher.</entry> | ||
77 | </row> | ||
78 | <row> | ||
79 | <entry>struct <link linkend="v4l2-rect-crop">v4l2_rect</link></entry> | ||
80 | <entry><structfield>bounds</structfield></entry> | ||
81 | <entry>Defines the window within capturing or output is | ||
82 | possible, this may exclude for example the horizontal and vertical | ||
83 | blanking areas. The cropping rectangle cannot exceed these limits. | ||
84 | Width and height are defined in pixels, the driver writer is free to | ||
85 | choose origin and units of the coordinate system in the analog | ||
86 | domain.</entry> | ||
87 | </row> | ||
88 | <row> | ||
89 | <entry>struct <link linkend="v4l2-rect-crop">v4l2_rect</link></entry> | ||
90 | <entry><structfield>defrect</structfield></entry> | ||
91 | <entry>Default cropping rectangle, it shall cover the | ||
92 | "whole picture". Assuming pixel aspect 1/1 this could be for example a | ||
93 | 640 × 480 rectangle for NTSC, a | ||
94 | 768 × 576 rectangle for PAL and SECAM centered over | ||
95 | the active picture area. The same co-ordinate system as for | ||
96 | <structfield>bounds</structfield> is used.</entry> | ||
97 | </row> | ||
98 | <row> | ||
99 | <entry>&v4l2-fract;</entry> | ||
100 | <entry><structfield>pixelaspect</structfield></entry> | ||
101 | <entry><para>This is the pixel aspect (y / x) when no | ||
102 | scaling is applied, the ratio of the actual sampling | ||
103 | frequency and the frequency required to get square | ||
104 | pixels.</para><para>When cropping coordinates refer to square pixels, | ||
105 | the driver sets <structfield>pixelaspect</structfield> to 1/1. Other | ||
106 | common values are 54/59 for PAL and SECAM, 11/10 for NTSC sampled | ||
107 | according to [<xref linkend="itu601" />].</para></entry> | ||
108 | </row> | ||
109 | </tbody> | ||
110 | </tgroup> | ||
111 | </table> | ||
112 | |||
113 | <!-- NB this table is duplicated in the overlay chapter. --> | ||
114 | |||
115 | <table pgwide="1" frame="none" id="v4l2-rect-crop"> | ||
116 | <title>struct <structname>v4l2_rect</structname></title> | ||
117 | <tgroup cols="3"> | ||
118 | &cs-str; | ||
119 | <tbody valign="top"> | ||
120 | <row> | ||
121 | <entry>__s32</entry> | ||
122 | <entry><structfield>left</structfield></entry> | ||
123 | <entry>Horizontal offset of the top, left corner of the | ||
124 | rectangle, in pixels.</entry> | ||
125 | </row> | ||
126 | <row> | ||
127 | <entry>__s32</entry> | ||
128 | <entry><structfield>top</structfield></entry> | ||
129 | <entry>Vertical offset of the top, left corner of the | ||
130 | rectangle, in pixels.</entry> | ||
131 | </row> | ||
132 | <row> | ||
133 | <entry>__s32</entry> | ||
134 | <entry><structfield>width</structfield></entry> | ||
135 | <entry>Width of the rectangle, in pixels.</entry> | ||
136 | </row> | ||
137 | <row> | ||
138 | <entry>__s32</entry> | ||
139 | <entry><structfield>height</structfield></entry> | ||
140 | <entry>Height of the rectangle, in pixels. Width | ||
141 | and height cannot be negative, the fields are signed for | ||
142 | hysterical reasons. <!-- video4linux-list@redhat.com | ||
143 | on 22 Oct 2002 subject "Re:[V4L][patches!] Re:v4l2/kernel-2.5" --> | ||
144 | </entry> | ||
145 | </row> | ||
146 | </tbody> | ||
147 | </tgroup> | ||
148 | </table> | ||
149 | </refsect1> | ||
150 | |||
151 | <refsect1> | ||
152 | &return-value; | ||
153 | |||
154 | <variablelist> | ||
155 | <varlistentry> | ||
156 | <term><errorcode>EINVAL</errorcode></term> | ||
157 | <listitem> | ||
158 | <para>The &v4l2-cropcap; <structfield>type</structfield> is | ||
159 | invalid or the ioctl is not supported. This is not permitted for | ||
160 | video capture, output and overlay devices, which must support | ||
161 | <constant>VIDIOC_CROPCAP</constant>.</para> | ||
162 | </listitem> | ||
163 | </varlistentry> | ||
164 | </variablelist> | ||
165 | </refsect1> | ||
166 | </refentry> | ||
167 | |||
168 | <!-- | ||
169 | Local Variables: | ||
170 | mode: sgml | ||
171 | sgml-parent-document: "v4l2.sgml" | ||
172 | indent-tabs-mode: nil | ||
173 | End: | ||
174 | --> | ||