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-rw-r--r--Documentation/DocBook/media/v4l/selection-api.xml22
1 files changed, 11 insertions, 11 deletions
diff --git a/Documentation/DocBook/media/v4l/selection-api.xml b/Documentation/DocBook/media/v4l/selection-api.xml
index e7ed5077834d..4c238ce068b0 100644
--- a/Documentation/DocBook/media/v4l/selection-api.xml
+++ b/Documentation/DocBook/media/v4l/selection-api.xml
@@ -40,6 +40,7 @@ cropping and composing rectangles have the same size.</para>
40 <section> 40 <section>
41 <title>Selection targets</title> 41 <title>Selection targets</title>
42 42
43 <para>
43 <figure id="sel-targets-capture"> 44 <figure id="sel-targets-capture">
44 <title>Cropping and composing targets</title> 45 <title>Cropping and composing targets</title>
45 <mediaobject> 46 <mediaobject>
@@ -52,12 +53,12 @@ cropping and composing rectangles have the same size.</para>
52 </textobject> 53 </textobject>
53 </mediaobject> 54 </mediaobject>
54 </figure> 55 </figure>
56 </para>
55 57
58 <para>See <xref linkend="v4l2-selection-targets" /> for more
59 information.</para>
56 </section> 60 </section>
57 61
58 See <xref linkend="v4l2-selection-targets" /> for more
59 information.
60
61 <section> 62 <section>
62 63
63 <title>Configuration</title> 64 <title>Configuration</title>
@@ -216,18 +217,17 @@ composing and cropping operations by setting the appropriate targets. The V4L2
216API lacks any support for composing to and cropping from an image inside a 217API lacks any support for composing to and cropping from an image inside a
217memory buffer. The application could configure a capture device to fill only a 218memory buffer. The application could configure a capture device to fill only a
218part of an image by abusing V4L2 API. Cropping a smaller image from a larger 219part of an image by abusing V4L2 API. Cropping a smaller image from a larger
219one is achieved by setting the field <structfield> 220one is achieved by setting the field
220&v4l2-pix-format;::bytesperline </structfield>. Introducing an image offsets 221&v4l2-pix-format;<structfield>::bytesperline</structfield>. Introducing an image offsets
221could be done by modifying field <structfield> &v4l2-buffer;::m:userptr 222could be done by modifying field &v4l2-buffer;<structfield>::m_userptr</structfield>
222</structfield> before calling <constant> VIDIOC_QBUF </constant>. Those 223before calling <constant> VIDIOC_QBUF </constant>. Those
223operations should be avoided because they are not portable (endianness), and do 224operations should be avoided because they are not portable (endianness), and do
224not work for macroblock and Bayer formats and mmap buffers. The selection API 225not work for macroblock and Bayer formats and mmap buffers. The selection API
225deals with configuration of buffer cropping/composing in a clear, intuitive and 226deals with configuration of buffer cropping/composing in a clear, intuitive and
226portable way. Next, with the selection API the concepts of the padded target 227portable way. Next, with the selection API the concepts of the padded target
227and constraints flags are introduced. Finally, <structname> &v4l2-crop; 228and constraints flags are introduced. Finally, &v4l2-crop; and &v4l2-cropcap;
228</structname> and <structname> &v4l2-cropcap; </structname> have no reserved 229have no reserved fields. Therefore there is no way to extend their functionality.
229fields. Therefore there is no way to extend their functionality. The new 230The new &v4l2-selection; provides a lot of place for future
230<structname> &v4l2-selection; </structname> provides a lot of place for future
231extensions. Driver developers are encouraged to implement only selection API. 231extensions. Driver developers are encouraged to implement only selection API.
232The former cropping API would be simulated using the new one. </para> 232The former cropping API would be simulated using the new one. </para>
233 233