[PATCH wayland-protocols v3 1/5] stable: add viewporter draft

[Derek Foreman]

On 26/04/16 07:50 AM, Pekka Paalanen wrote:
> From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> 
> This XML file has been copied verbatim from Weston 1.10.0 release,
> protocol/scaler.xml.
> 
> The interfaces still need renaming according to wayland-protocols
> policy. Also a redundant request needs to be removed. These will be done
> in a follow-up patch to clearly show the changes.
> 
> Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> Reviewed-by: Yong Bakos <ybakos at humanoriented.com>
> Reviewed-by: Daniel Stone <daniels at collabora.com>
> ---
>  stable/viewporter/README         |   7 ++
>  stable/viewporter/viewporter.xml | 208 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 215 insertions(+)
>  create mode 100644 stable/viewporter/README
>  create mode 100644 stable/viewporter/viewporter.xml
> 
> diff --git a/stable/viewporter/README b/stable/viewporter/README
> new file mode 100644
> index 0000000..e09057b
> --- /dev/null
> +++ b/stable/viewporter/README
> @@ -0,0 +1,7 @@
> +Viewporter: cropping and scaling extension for surface contents
> +
> +Previously known as wl_scaler.
> +
> +Maintainers:
> +Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> +
> diff --git a/stable/viewporter/viewporter.xml b/stable/viewporter/viewporter.xml
> new file mode 100644
> index 0000000..0e482a6
> --- /dev/null
> +++ b/stable/viewporter/viewporter.xml
> @@ -0,0 +1,208 @@
> +<?xml version="1.0" encoding="UTF-8"?>
> +<protocol name="scaler">
> +
> +  <copyright>
> +    Copyright © 2013-2014 Collabora, Ltd.
> +
> +    Permission is hereby granted, free of charge, to any person obtaining a
> +    copy of this software and associated documentation files (the "Software"),
> +    to deal in the Software without restriction, including without limitation
> +    the rights to use, copy, modify, merge, publish, distribute, sublicense,
> +    and/or sell copies of the Software, and to permit persons to whom the
> +    Software is furnished to do so, subject to the following conditions:
> +
> +    The above copyright notice and this permission notice (including the next
> +    paragraph) shall be included in all copies or substantial portions of the
> +    Software.
> +
> +    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> +    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> +    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> +    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> +    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> +    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> +    DEALINGS IN THE SOFTWARE.
> +  </copyright>
> +
> +  <interface name="wl_scaler" version="2">
> +    <description summary="surface cropping and scaling">
> +      The global interface exposing surface cropping and scaling
> +      capabilities is used to instantiate an interface extension for a
> +      wl_surface object. This extended interface will then allow
> +      cropping and scaling the surface contents, effectively
> +      disconnecting the direct relationship between the buffer and the
> +      surface size.
> +    </description>
> +
> +    <request name="destroy" type="destructor">
> +      <description summary="unbind from the cropping and scaling interface">
> +	Informs the server that the client will not be using this
> +	protocol object anymore. This does not affect any other objects,
> +	wl_viewport objects included.
> +      </description>
> +    </request>
> +
> +    <enum name="error">
> +      <entry name="viewport_exists" value="0"
> +             summary="the surface already has a viewport object associated"/>
> +    </enum>
> +
> +    <request name="get_viewport">
> +      <description summary="extend surface interface for crop and scale">
> +	Instantiate an interface extension for the given wl_surface to
> +	crop and scale its content. If the given wl_surface already has
> +	a wl_viewport object associated, the viewport_exists
> +	protocol error is raised.
> +      </description>
> +
> +      <arg name="id" type="new_id" interface="wl_viewport"
> +           summary="the new viewport interface id"/>
> +      <arg name="surface" type="object" interface="wl_surface"
> +           summary="the surface"/>
> +    </request>
> +  </interface>
> +
> +  <interface name="wl_viewport" version="2">
> +    <description summary="crop and scale interface to a wl_surface">
> +      An additional interface to a wl_surface object, which allows the
> +      client to specify the cropping and scaling of the surface
> +      contents.
> +
> +      This interface allows to define the source rectangle (src_x,
> +      src_y, src_width, src_height) from where to take the wl_buffer
> +      contents, and scale that to destination size (dst_width,
> +      dst_height). This state is double-buffered, and is applied on the
> +      next wl_surface.commit.
> +
> +      The two parts of crop and scale state are independent: the source
> +      rectangle, and the destination size. Initially both are unset, that
> +      is, no scaling is applied. The whole of the current wl_buffer is
> +      used as the source, and the surface size is as defined in
> +      wl_surface.attach.
> +
> +      If the destination size is set, it causes the surface size to become
> +      dst_width, dst_height. The source (rectangle) is scaled to exactly
> +      this size. This overrides whatever the attached wl_buffer size is,
> +      unless the wl_buffer is NULL. If the wl_buffer is NULL, the surface
> +      has no content and therefore no size. Otherwise, the size is always
> +      at least 1x1 in surface coordinates.
> +
> +      If the source rectangle is set, it defines what area of the
> +      wl_buffer is taken as the source. If the source rectangle is set and
> +      the destination size is not set, the surface size becomes the source
> +      rectangle size rounded up to the nearest integer. If the source size
> +      is already exactly integers, this results in cropping without scaling.
> +
> +      The coordinate transformations from buffer pixel coordinates up to
> +      the surface-local coordinates happen in the following order:
> +        1. buffer_transform (wl_surface.set_buffer_transform)
> +        2. buffer_scale (wl_surface.set_buffer_scale)
> +        3. crop and scale (wl_viewport.set*)
> +      This means, that the source rectangle coordinates of crop and scale
> +      are given in the coordinates after the buffer transform and scale,
> +      i.e. in the coordinates that would be the surface-local coordinates
> +      if the crop and scale was not applied.
> +
> +      If the source rectangle is partially or completely outside of the
> +      wl_buffer, then the surface contents are undefined (not void), and
> +      the surface size is still dst_width, dst_height.
> +
> +      The x, y arguments of wl_surface.attach are applied as normal to

I'm a little uncomfortable with "applied as normal to".  In geometry,
when something is normal to a surface it's perpendicular to it, but I
think here we're trying to say x and y are in surface co-ordinates?

> +      the surface. They indicate how many pixels to remove from the
> +      surface size from the left and the top. In other words, they are

I prefer this "in other words" explanation. :)

Otherwise,
Reviewed-by: Derek Foreman <derekf at osg.samsung.com>

> +      still in the surface-local coordinate system, just like dst_width
> +      and dst_height are.
> +
> +      If the wl_surface associated with the wl_viewport is destroyed,
> +      the wl_viewport object becomes inert.
> +
> +      If the wl_viewport object is destroyed, the crop and scale
> +      state is removed from the wl_surface. The change will be applied
> +      on the next wl_surface.commit.
> +    </description>
> +
> +    <request name="destroy" type="destructor">
> +      <description summary="remove scaling and cropping from the surface">
> +	The associated wl_surface's crop and scale state is removed.
> +	The change is applied on the next wl_surface.commit.
> +      </description>
> +    </request>
> +
> +    <enum name="error">
> +      <entry name="bad_value" value="0"
> +             summary="negative or zero values in width or height"/>
> +    </enum>
> +
> +    <request name="set">
> +      <description summary="set the crop and scale state">
> +	Set both source rectangle and destination size of the associated
> +	wl_surface. See wl_viewport for the description, and relation to
> +	the wl_buffer size.
> +
> +	The bad_value protocol error is raised if src_width or
> +	src_height is negative, or if dst_width or dst_height is not
> +	positive.
> +
> +	The crop and scale state is double-buffered state, and will be
> +	applied on the next wl_surface.commit.
> +
> +	Arguments dst_x and dst_y do not exist here, use the x and y
> +	arguments to wl_surface.attach. The x, y, dst_width, and dst_height
> +	define the surface-local coordinate system irrespective of the
> +	attached wl_buffer size.
> +      </description>
> +
> +      <arg name="src_x" type="fixed" summary="source rectangle x"/>
> +      <arg name="src_y" type="fixed" summary="source rectangle y"/>
> +      <arg name="src_width" type="fixed" summary="source rectangle width"/>
> +      <arg name="src_height" type="fixed" summary="source rectangle height"/>
> +      <arg name="dst_width" type="int" summary="surface width"/>
> +      <arg name="dst_height" type="int" summary="surface height"/>
> +    </request>
> +
> +    <request name="set_source" since="2">
> +      <description summary="set the source rectangle for cropping">
> +	Set the source rectangle of the associated wl_surface. See
> +	wl_viewport for the description, and relation to the wl_buffer
> +	size.
> +
> +	If width is -1.0 and height is -1.0, the source rectangle is unset
> +	instead. Any other pair of values for width and height that
> +	contains zero or negative values raises the bad_value protocol
> +	error.
> +
> +	The crop and scale state is double-buffered state, and will be
> +	applied on the next wl_surface.commit.
> +      </description>
> +
> +      <arg name="x" type="fixed" summary="source rectangle x"/>
> +      <arg name="y" type="fixed" summary="source rectangle y"/>
> +      <arg name="width" type="fixed" summary="source rectangle width"/>
> +      <arg name="height" type="fixed" summary="source rectangle height"/>
> +    </request>
> +
> +    <request name="set_destination" since="2">
> +      <description summary="set the surface size for scaling">
> +	Set the destination size of the associated wl_surface. See
> +	wl_viewport for the description, and relation to the wl_buffer
> +	size.
> +
> +	If width is -1 and height is -1, the destination size is unset
> +	instead. Any other pair of values for width and height that
> +	contains zero or negative values raises the bad_value protocol
> +	error.
> +
> +	The crop and scale state is double-buffered state, and will be
> +	applied on the next wl_surface.commit.
> +
> +	Arguments x and y do not exist here, use the x and y arguments to
> +	wl_surface.attach. The x, y, width, and height define the
> +	surface-local coordinate system irrespective of the attached
> +	wl_buffer size.
> +      </description>
> +
> +      <arg name="width" type="int" summary="surface width"/>
> +      <arg name="height" type="int" summary="surface height"/>
> +    </request>
> +  </interface>
> +</protocol>
>