diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/DocBook/media/v4l/selection-api.xml | 30 |
1 files changed, 12 insertions, 18 deletions
diff --git a/Documentation/DocBook/media/v4l/selection-api.xml b/Documentation/DocBook/media/v4l/selection-api.xml index 46cb47ab8e3b..2f0bdb4d5551 100644 --- a/Documentation/DocBook/media/v4l/selection-api.xml +++ b/Documentation/DocBook/media/v4l/selection-api.xml @@ -84,9 +84,7 @@ configure the cropping targets before to the composing targets.</para> areas that can be sampled is given by the <constant> V4L2_SEL_TGT_CROP_BOUNDS </constant> target. It is recommended for the driver developers to put the top/left corner at position <constant> (0,0) </constant>. The rectangle's -coordinates are expressed in driver dependant units, although the coordinate -system guarantees that if sizes of the active cropping and the active composing -rectangles are equal then no scaling is performed. </para> +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 @@ -103,10 +101,10 @@ not later.</para> <para>The composing targets refer to a memory buffer. The limits of composing coordinates are obtained using <constant> V4L2_SEL_TGT_COMPOSE_BOUNDS -</constant>. All coordinates are expressed in natural unit for given formats. -Pixels are highly recommended. The rectangle's top/left corner must be located -at position <constant> (0,0) </constant>. The width and height are equal to the -image size set by <constant> VIDIOC_S_FMT </constant>.</para> +</constant>. All coordinates are expressed in pixels. The rectangle's top/left +corner must be located at position <constant> (0,0) </constant>. The width and +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. @@ -145,10 +143,9 @@ the cropping targets.</para> <para>The cropping targets refer to the memory buffer that contains an image to be inserted into a video signal or graphical screen. The limits of cropping coordinates are obtained using <constant> V4L2_SEL_TGT_CROP_BOUNDS </constant>. -All coordinates are expressed in natural units for a given format. Pixels are -highly recommended. The top/left corner is always point <constant> (0,0) -</constant>. The width and height is equal to the image size specified using -<constant> VIDIOC_S_FMT </constant> ioctl.</para> +All coordinates are expressed in pixels. The top/left corner is always point +<constant> (0,0) </constant>. The width and height is equal to the image size +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 @@ -163,13 +160,10 @@ limitations.</para> 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 are expressed in driver -dependant units. The only exception are digital outputs where the units are -pixels. For other types of devices, the coordinate system guarantees that if -sizes of the active cropping and the active composing rectangles are equal then -no scaling is performed. The composing rectangle must lie completely inside -the bounds rectangle. The driver must adjust the area to fit to the bounding +inserted by the hardware is controlled by <constant> +V4L2_SEL_TGT_COMPOSE_ACTIVE </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 hardware limitations. </para> |