mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-26 15:05:24 +07:00
8780f1d9d6
Unfortunately the use of 'type' was inconsistent for multiplanar buffer types. Starting with 4.13 both the normal and _MPLANE variants are allowed, thus making it possible to write sensible code. Yes, we messed up :-( Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> [hans.verkuil@cisco.com: 4.14 -> 4.13 since this would go in for 4.13 after all] Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
112 lines
3.8 KiB
ReStructuredText
112 lines
3.8 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
|
|
|
|
.. _VIDIOC_G_CROP:
|
|
|
|
**********************************
|
|
ioctl VIDIOC_G_CROP, VIDIOC_S_CROP
|
|
**********************************
|
|
|
|
Name
|
|
====
|
|
|
|
VIDIOC_G_CROP - VIDIOC_S_CROP - Get or set the current cropping rectangle
|
|
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_G_CROP, struct v4l2_crop *argp )
|
|
:name: VIDIOC_G_CROP
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_S_CROP, const struct v4l2_crop *argp )
|
|
:name: VIDIOC_S_CROP
|
|
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :ref:`open() <func-open>`.
|
|
|
|
``argp``
|
|
|
|
|
|
Description
|
|
===========
|
|
|
|
To query the cropping rectangle size and position applications set the
|
|
``type`` field of a struct :c:type:`v4l2_crop` structure to the
|
|
respective buffer (stream) type and call the :ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` ioctl
|
|
with a pointer to this structure. The driver fills the rest of the
|
|
structure or returns the ``EINVAL`` error code if cropping is not supported.
|
|
|
|
To change the cropping rectangle applications initialize the ``type``
|
|
and struct :c:type:`v4l2_rect` substructure named ``c`` of a
|
|
v4l2_crop structure and call the :ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` ioctl with a pointer
|
|
to this structure.
|
|
|
|
The driver first adjusts the requested dimensions against hardware
|
|
limits, i. e. the bounds given by the capture/output window, and it
|
|
rounds to the closest possible values of horizontal and vertical offset,
|
|
width and height. In particular the driver must round the vertical
|
|
offset of the cropping rectangle to frame lines modulo two, such that
|
|
the field order cannot be confused.
|
|
|
|
Second the driver adjusts the image size (the opposite rectangle of the
|
|
scaling process, source or target depending on the data direction) to
|
|
the closest size possible while maintaining the current horizontal and
|
|
vertical scaling factor.
|
|
|
|
Finally the driver programs the hardware with the actual cropping and
|
|
image parameters. :ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` is a write-only ioctl, it does not
|
|
return the actual parameters. To query them applications must call
|
|
:ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` and :ref:`VIDIOC_G_FMT`. When the
|
|
parameters are unsuitable the application may modify the cropping or
|
|
image parameters and repeat the cycle until satisfactory parameters have
|
|
been negotiated.
|
|
|
|
When cropping is not supported then no parameters are changed and
|
|
:ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` returns the ``EINVAL`` error code.
|
|
|
|
|
|
.. c:type:: v4l2_crop
|
|
|
|
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
|
|
|
|
.. flat-table:: struct v4l2_crop
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 1 1 2
|
|
|
|
* - __u32
|
|
- ``type``
|
|
- Type of the data stream, set by the application. Only these types
|
|
are valid here: ``V4L2_BUF_TYPE_VIDEO_CAPTURE``, ``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE``,
|
|
``V4L2_BUF_TYPE_VIDEO_OUTPUT``, ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE`` and
|
|
``V4L2_BUF_TYPE_VIDEO_OVERLAY``. See :c:type:`v4l2_buf_type` and the note above.
|
|
* - struct :c:type:`v4l2_rect`
|
|
- ``c``
|
|
- Cropping rectangle. The same co-ordinate system as for struct
|
|
:c:type:`v4l2_cropcap` ``bounds`` is used.
|
|
|
|
.. note::
|
|
Unfortunately in the case of multiplanar buffer types
|
|
(``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE`` and ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``)
|
|
this API was messed up with regards to how the :c:type:`v4l2_crop` ``type`` field
|
|
should be filled in. Some drivers only accepted the ``_MPLANE`` buffer type while
|
|
other drivers only accepted a non-multiplanar buffer type (i.e. without the
|
|
``_MPLANE`` at the end).
|
|
|
|
Starting with kernel 4.13 both variations are allowed.
|
|
|
|
|
|
Return Value
|
|
============
|
|
|
|
On success 0 is returned, on error -1 and the ``errno`` variable is set
|
|
appropriately. The generic error codes are described at the
|
|
:ref:`Generic Error Codes <gen-errors>` chapter.
|
|
|
|
ENODATA
|
|
Cropping is not supported for this input or output.
|