From aa73ab96bebb6fb9e0ee4429f78bfa3ef8c5b6b6 Mon Sep 17 00:00:00 2001 From: Tomasz Stanislawski Date: Fri, 9 Dec 2011 13:45:47 -0300 Subject: [PATCH] [media] doc: v4l: selection: choose pixels as units for selection rectangles Pixels were preferred units for selection rectangles over driver-dependent units for almost all use cases. Therefore the units were fixed to pixels. Signed-off-by: Tomasz Stanislawski Signed-off-by: Kyungmin Park Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/selection-api.xml | 30 +++++++++-------------- 1 file changed, 12 insertions(+), 18 deletions(-) diff --git a/Documentation/DocBook/media/v4l/selection-api.xml b/Documentation/DocBook/media/v4l/selection-api.xml index 46cb47a..2f0bdb4 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. areas that can be sampled is given by the V4L2_SEL_TGT_CROP_BOUNDS target. It is recommended for the driver developers to put the top/left corner at position (0,0) . 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. +coordinates are expressed in pixels. The top left corner, width and height of the source rectangle, that is the area actually sampled, is given by the V4L2_SEL_TGT_CROP_ACTIVE @@ -103,10 +101,10 @@ not later. The composing targets refer to a memory buffer. The limits of composing coordinates are obtained using V4L2_SEL_TGT_COMPOSE_BOUNDS -. 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 (0,0) . The width and height are equal to the -image size set by VIDIOC_S_FMT . +. All coordinates are expressed in pixels. The rectangle's top/left +corner must be located at position (0,0) . The width and +height are equal to the image size set by VIDIOC_S_FMT . + The part of a buffer into which the image is inserted by the hardware is controlled by the V4L2_SEL_TGT_COMPOSE_ACTIVE target. @@ -145,10 +143,9 @@ the cropping targets. 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 V4L2_SEL_TGT_CROP_BOUNDS . -All coordinates are expressed in natural units for a given format. Pixels are -highly recommended. The top/left corner is always point (0,0) -. The width and height is equal to the image size specified using - VIDIOC_S_FMT ioctl. +All coordinates are expressed in pixels. The top/left corner is always point + (0,0) . The width and height is equal to the image size +specified using VIDIOC_S_FMT ioctl. 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. bounding rectangle. The part of a video signal or graphics display where the image is -inserted by the hardware is controlled by V4L2_SEL_TGT_COMPOSE_ACTIVE - 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 +V4L2_SEL_TGT_COMPOSE_ACTIVE 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. -- 2.7.4