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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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210 lines
9 KiB
XML
210 lines
9 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<protocol name="scaler">
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<copyright>
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Copyright © 2013-2014 Collabora, Ltd.
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Permission to use, copy, modify, distribute, and sell this
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software and its documentation for any purpose is hereby granted
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without fee, provided that the above copyright notice appear in
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all copies and that both that copyright notice and this permission
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notice appear in supporting documentation, and that the name of
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the copyright holders not be used in advertising or publicity
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pertaining to distribution of the software without specific,
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written prior permission. The copyright holders make no
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representations about the suitability of this software for any
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purpose. It is provided "as is" without express or implied
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warranty.
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THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
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SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
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SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
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AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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THIS SOFTWARE.
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</copyright>
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<interface name="wl_scaler" version="2">
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<description summary="surface cropping and scaling">
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The global interface exposing surface cropping and scaling
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capabilities is used to instantiate an interface extension for a
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wl_surface object. This extended interface will then allow
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cropping and scaling the surface contents, effectively
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disconnecting the direct relationship between the buffer and the
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surface size.
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</description>
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<request name="destroy" type="destructor">
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<description summary="unbind from the cropping and scaling interface">
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Informs the server that the client will not be using this
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protocol object anymore. This does not affect any other objects,
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wl_viewport objects included.
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</description>
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</request>
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<enum name="error">
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<entry name="viewport_exists" value="0"
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summary="the surface already has a viewport object associated"/>
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</enum>
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<request name="get_viewport">
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<description summary="extend surface interface for crop and scale">
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Instantiate an interface extension for the given wl_surface to
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crop and scale its content. If the given wl_surface already has
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a wl_viewport object associated, the viewport_exists
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protocol error is raised.
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</description>
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<arg name="id" type="new_id" interface="wl_viewport"
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summary="the new viewport interface id"/>
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<arg name="surface" type="object" interface="wl_surface"
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summary="the surface"/>
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</request>
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</interface>
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<interface name="wl_viewport" version="2">
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<description summary="crop and scale interface to a wl_surface">
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An additional interface to a wl_surface object, which allows the
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client to specify the cropping and scaling of the surface
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contents.
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This interface allows to define the source rectangle (src_x,
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src_y, src_width, src_height) from where to take the wl_buffer
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contents, and scale that to destination size (dst_width,
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dst_height). This state is double-buffered, and is applied on the
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next wl_surface.commit.
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The two parts of crop and scale state are independent: the source
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rectangle, and the destination size. Initially both are unset, that
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is, no scaling is applied. The whole of the current wl_buffer is
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used as the source, and the surface size is as defined in
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wl_surface.attach.
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If the destination size is set, it causes the surface size to become
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dst_width, dst_height. The source (rectangle) is scaled to exactly
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this size. This overrides whatever the attached wl_buffer size is,
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unless the wl_buffer is NULL. If the wl_buffer is NULL, the surface
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has no content and therefore no size. Otherwise, the size is always
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at least 1x1 in surface coordinates.
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If the source rectangle is set, it defines what area of the
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wl_buffer is taken as the source. If the source rectangle is set and
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the destination size is not set, the surface size becomes the source
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rectangle size rounded up to the nearest integer. If the source size
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is already exactly integers, this results in cropping without scaling.
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The coordinate transformations from buffer pixel coordinates up to
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the surface-local coordinates happen in the following order:
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1. buffer_transform (wl_surface.set_buffer_transform)
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2. buffer_scale (wl_surface.set_buffer_scale)
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3. crop and scale (wl_viewport.set*)
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This means, that the source rectangle coordinates of crop and scale
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are given in the coordinates after the buffer transform and scale,
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i.e. in the coordinates that would be the surface-local coordinates
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if the crop and scale was not applied.
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If the source rectangle is partially or completely outside of the
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wl_buffer, then the surface contents are undefined (not void), and
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the surface size is still dst_width, dst_height.
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The x, y arguments of wl_surface.attach are applied as normal to
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the surface. They indicate how many pixels to remove from the
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surface size from the left and the top. In other words, they are
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still in the surface-local coordinate system, just like dst_width
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and dst_height are.
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If the wl_surface associated with the wl_viewport is destroyed,
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the wl_viewport object becomes inert.
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If the wl_viewport object is destroyed, the crop and scale
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state is removed from the wl_surface. The change will be applied
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on the next wl_surface.commit.
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</description>
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<request name="destroy" type="destructor">
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<description summary="remove scaling and cropping from the surface">
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The associated wl_surface's crop and scale state is removed.
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The change is applied on the next wl_surface.commit.
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</description>
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</request>
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<enum name="error">
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<entry name="bad_value" value="0"
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summary="negative or zero values in width or height"/>
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</enum>
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<request name="set">
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<description summary="set the crop and scale state">
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Set both source rectangle and destination size of the associated
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wl_surface. See wl_viewport for the description, and relation to
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the wl_buffer size.
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The bad_value protocol error is raised if src_width or
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src_height is negative, or if dst_width or dst_height is not
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positive.
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The crop and scale state is double-buffered state, and will be
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applied on the next wl_surface.commit.
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Arguments dst_x and dst_y do not exist here, use the x and y
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arguments to wl_surface.attach. The x, y, dst_width, and dst_height
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define the surface-local coordinate system irrespective of the
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attached wl_buffer size.
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</description>
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<arg name="src_x" type="fixed" summary="source rectangle x"/>
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<arg name="src_y" type="fixed" summary="source rectangle y"/>
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<arg name="src_width" type="fixed" summary="source rectangle width"/>
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<arg name="src_height" type="fixed" summary="source rectangle height"/>
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<arg name="dst_width" type="int" summary="surface width"/>
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<arg name="dst_height" type="int" summary="surface height"/>
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</request>
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<request name="set_source" since="2">
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<description summary="set the source rectangle for cropping">
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Set the source rectangle of the associated wl_surface. See
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wl_viewport for the description, and relation to the wl_buffer
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size.
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If width is -1.0 and height is -1.0, the destination size is unset
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instead. Any other pair of values for width and height that
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contains zero or negative values raises the bad_value protocol
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error.
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The crop and scale state is double-buffered state, and will be
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applied on the next wl_surface.commit.
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</description>
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<arg name="x" type="fixed" summary="source rectangle x"/>
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<arg name="y" type="fixed" summary="source rectangle y"/>
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<arg name="width" type="fixed" summary="source rectangle width"/>
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<arg name="height" type="fixed" summary="source rectangle height"/>
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</request>
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<request name="set_destination" since="2">
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<description summary="set the surface size for scaling">
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Set the destination size of the associated wl_surface. See
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wl_viewport for the description, and relation to the wl_buffer
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size.
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If width is -1 and height is -1, the destination size is unset
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instead. Any other pair of values for width and height that
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contains zero or negative values raises the bad_value protocol
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error.
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The crop and scale state is double-buffered state, and will be
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applied on the next wl_surface.commit.
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Arguments x and y do not exist here, use the x and y arguments to
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wl_surface.attach. The x, y, width, and height define the
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surface-local coordinate system irrespective of the attached
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wl_buffer size.
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</description>
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<arg name="width" type="int" summary="surface width"/>
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<arg name="height" type="int" summary="surface height"/>
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</request>
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</interface>
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</protocol>
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