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-rw-r--r--Documentation/DocBook/media/v4l/selection-api.xml50
1 files changed, 25 insertions, 25 deletions
diff --git a/Documentation/DocBook/media/v4l/selection-api.xml b/Documentation/DocBook/media/v4l/selection-api.xml
index b299e477935..4c238ce068b 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>
<section>
<title>Selection targets</title>
+ <para>
<figure id="sel-targets-capture">
<title>Cropping and composing targets</title>
<mediaobject>
@@ -52,10 +53,10 @@ cropping and composing rectangles have the same size.</para>
</textobject>
</mediaobject>
</figure>
+ </para>
-For complete list of the available selection targets see table <xref
-linkend="v4l2-sel-target"/>
-
+ <para>See <xref linkend="v4l2-selection-targets" /> for more
+ information.</para>
</section>
<section>
@@ -74,7 +75,7 @@ cropping/composing rectangles may have to be aligned, and both the source and
the sink may have arbitrary upper and lower size limits. Therefore, as usual,
drivers are expected to adjust the requested parameters and return the actual
values selected. An application can control the rounding behaviour using <link
-linkend="v4l2-sel-flags"> constraint flags </link>.</para>
+linkend="v4l2-selection-flags"> constraint flags </link>.</para>
<section>
@@ -91,7 +92,7 @@ top/left corner at position <constant> (0,0) </constant>. The rectangle's
coordinates are expressed in pixels.</para>
<para>The top left corner, width and height of the source rectangle, that is
-the area actually sampled, is given by the <constant> V4L2_SEL_TGT_CROP_ACTIVE
+the area actually sampled, is given by the <constant> V4L2_SEL_TGT_CROP
</constant> target. It uses the same coordinate system as <constant>
V4L2_SEL_TGT_CROP_BOUNDS </constant>. The active cropping area must lie
completely inside the capture boundaries. The driver may further adjust the
@@ -111,13 +112,13 @@ height are equal to the image size set by <constant> VIDIOC_S_FMT </constant>.
</para>
<para>The part of a buffer into which the image is inserted by the hardware is
-controlled by the <constant> V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> target.
+controlled by the <constant> V4L2_SEL_TGT_COMPOSE </constant> target.
The rectangle's coordinates are also expressed in the same coordinate system as
the bounds rectangle. The composing rectangle must lie completely inside bounds
rectangle. The driver must adjust the composing rectangle to fit to the
bounding limits. Moreover, the driver can perform other adjustments according
to hardware limitations. The application can control rounding behaviour using
-<link linkend="v4l2-sel-flags"> constraint flags </link>.</para>
+<link linkend="v4l2-selection-flags"> constraint flags </link>.</para>
<para>For capture devices the default composing rectangle is queried using
<constant> V4L2_SEL_TGT_COMPOSE_DEFAULT </constant>. It is usually equal to the
@@ -125,7 +126,7 @@ bounding rectangle.</para>
<para>The part of a buffer that is modified by the hardware is given by
<constant> V4L2_SEL_TGT_COMPOSE_PADDED </constant>. It contains all pixels
-defined using <constant> V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> plus all
+defined using <constant> V4L2_SEL_TGT_COMPOSE </constant> plus all
padding data modified by hardware during insertion process. All pixels outside
this rectangle <emphasis>must not</emphasis> be changed by the hardware. The
content of pixels that lie inside the padded area but outside active area is
@@ -153,7 +154,7 @@ specified using <constant> VIDIOC_S_FMT </constant> ioctl.</para>
<para>The top left corner, width and height of the source rectangle, that is
the area from which image date are processed by the hardware, is given by the
-<constant> V4L2_SEL_TGT_CROP_ACTIVE </constant>. Its coordinates are expressed
+<constant> V4L2_SEL_TGT_CROP </constant>. Its coordinates are expressed
in in the same coordinate system as the bounds rectangle. The active cropping
area must lie completely inside the crop boundaries and the driver may further
adjust the requested size and/or position according to hardware
@@ -165,7 +166,7 @@ bounding rectangle.</para>
<para>The part of a video signal or graphics display where the image is
inserted by the hardware is controlled by <constant>
-V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> target. The rectangle's coordinates
+V4L2_SEL_TGT_COMPOSE </constant> target. The rectangle's coordinates
are expressed in pixels. The composing rectangle must lie completely inside the
bounds rectangle. The driver must adjust the area to fit to the bounding
limits. Moreover, the driver can perform other adjustments according to
@@ -184,7 +185,7 @@ such a padded area is driver-dependent feature not covered by this document.
Driver developers are encouraged to keep padded rectangle equal to active one.
The padded target is accessed by the <constant> V4L2_SEL_TGT_COMPOSE_PADDED
</constant> identifier. It must contain all pixels from the <constant>
-V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> target.</para>
+V4L2_SEL_TGT_COMPOSE </constant> target.</para>
</section>
@@ -193,8 +194,8 @@ V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> target.</para>
<title>Scaling control</title>
<para>An application can detect if scaling is performed by comparing the width
-and the height of rectangles obtained using <constant> V4L2_SEL_TGT_CROP_ACTIVE
-</constant> and <constant> V4L2_SEL_TGT_COMPOSE_ACTIVE </constant> targets. If
+and the height of rectangles obtained using <constant> V4L2_SEL_TGT_CROP
+</constant> and <constant> V4L2_SEL_TGT_COMPOSE </constant> targets. If
these are not equal then the scaling is applied. The application can compute
the scaling ratios using these values.</para>
@@ -216,18 +217,17 @@ composing and cropping operations by setting the appropriate targets. The V4L2
API lacks any support for composing to and cropping from an image inside a
memory buffer. The application could configure a capture device to fill only a
part of an image by abusing V4L2 API. Cropping a smaller image from a larger
-one is achieved by setting the field <structfield>
-&v4l2-pix-format;::bytesperline </structfield>. Introducing an image offsets
-could be done by modifying field <structfield> &v4l2-buffer;::m:userptr
-</structfield> before calling <constant> VIDIOC_QBUF </constant>. Those
+one is achieved by setting the field
+&v4l2-pix-format;<structfield>::bytesperline</structfield>. Introducing an image offsets
+could be done by modifying field &v4l2-buffer;<structfield>::m_userptr</structfield>
+before calling <constant> VIDIOC_QBUF </constant>. Those
operations should be avoided because they are not portable (endianness), and do
not work for macroblock and Bayer formats and mmap buffers. The selection API
deals with configuration of buffer cropping/composing in a clear, intuitive and
portable way. Next, with the selection API the concepts of the padded target
-and constraints flags are introduced. Finally, <structname> &v4l2-crop;
-</structname> and <structname> &v4l2-cropcap; </structname> have no reserved
-fields. Therefore there is no way to extend their functionality. The new
-<structname> &v4l2-selection; </structname> provides a lot of place for future
+and constraints flags are introduced. Finally, &v4l2-crop; and &v4l2-cropcap;
+have no reserved fields. Therefore there is no way to extend their functionality.
+The new &v4l2-selection; provides a lot of place for future
extensions. Driver developers are encouraged to implement only selection API.
The former cropping API would be simulated using the new one. </para>
@@ -252,7 +252,7 @@ area)</para>
ret = ioctl(fd, &VIDIOC-G-SELECTION;, &amp;sel);
if (ret)
exit(-1);
- sel.target = V4L2_SEL_TGT_CROP_ACTIVE;
+ sel.target = V4L2_SEL_TGT_CROP;
ret = ioctl(fd, &VIDIOC-S-SELECTION;, &amp;sel);
if (ret)
exit(-1);
@@ -281,7 +281,7 @@ area)</para>
r.left = sel.r.width / 4;
r.top = sel.r.height / 4;
sel.r = r;
- sel.target = V4L2_SEL_TGT_COMPOSE_ACTIVE;
+ sel.target = V4L2_SEL_TGT_COMPOSE;
sel.flags = V4L2_SEL_FLAG_LE;
ret = ioctl(fd, &VIDIOC-S-SELECTION;, &amp;sel);
if (ret)
@@ -298,11 +298,11 @@ V4L2_BUF_TYPE_VIDEO_OUTPUT </constant> for other devices</para>
&v4l2-selection; compose = {
.type = V4L2_BUF_TYPE_VIDEO_OUTPUT,
- .target = V4L2_SEL_TGT_COMPOSE_ACTIVE,
+ .target = V4L2_SEL_TGT_COMPOSE,
};
&v4l2-selection; crop = {
.type = V4L2_BUF_TYPE_VIDEO_OUTPUT,
- .target = V4L2_SEL_TGT_CROP_ACTIVE,
+ .target = V4L2_SEL_TGT_CROP,
};
double hscale, vscale;