1<?xml version="1.0" encoding="UTF-8"?>
2<protocol name="viewporter">
3
4 <copyright>
5 Copyright © 2013-2016 Collabora, Ltd.
6
7 Permission is hereby granted, free of charge, to any person obtaining a
8 copy of this software and associated documentation files (the "Software"),
9 to deal in the Software without restriction, including without limitation
10 the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 and/or sell copies of the Software, and to permit persons to whom the
12 Software is furnished to do so, subject to the following conditions:
13
14 The above copyright notice and this permission notice (including the next
15 paragraph) shall be included in all copies or substantial portions of the
16 Software.
17
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21 THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
24 DEALINGS IN THE SOFTWARE.
25 </copyright>
26
27 <interface name="wp_viewporter" version="1">
28 <description summary="surface cropping and scaling">
29 The global interface exposing surface cropping and scaling
30 capabilities is used to instantiate an interface extension for a
31 wl_surface object. This extended interface will then allow
32 cropping and scaling the surface contents, effectively
33 disconnecting the direct relationship between the buffer and the
34 surface size.
35 </description>
36
37 <request name="destroy" type="destructor">
38 <description summary="unbind from the cropping and scaling interface">
39 Informs the server that the client will not be using this
40 protocol object anymore. This does not affect any other objects,
41 wp_viewport objects included.
42 </description>
43 </request>
44
45 <enum name="error">
46 <entry name="viewport_exists" value="0"
47 summary="the surface already has a viewport object associated"/>
48 </enum>
49
50 <request name="get_viewport">
51 <description summary="extend surface interface for crop and scale">
52 Instantiate an interface extension for the given wl_surface to
53 crop and scale its content. If the given wl_surface already has
54 a wp_viewport object associated, the viewport_exists
55 protocol error is raised.
56 </description>
57 <arg name="id" type="new_id" interface="wp_viewport"
58 summary="the new viewport interface id"/>
59 <arg name="surface" type="object" interface="wl_surface"
60 summary="the surface"/>
61 </request>
62 </interface>
63
64 <interface name="wp_viewport" version="1">
65 <description summary="crop and scale interface to a wl_surface">
66 An additional interface to a wl_surface object, which allows the
67 client to specify the cropping and scaling of the surface
68 contents.
69
70 This interface works with two concepts: the source rectangle (src_x,
71 src_y, src_width, src_height), and the destination size (dst_width,
72 dst_height). The contents of the source rectangle are scaled to the
73 destination size, and content outside the source rectangle is ignored.
74 This state is double-buffered, see wl_surface.commit.
75
76 The two parts of crop and scale state are independent: the source
77 rectangle, and the destination size. Initially both are unset, that
78 is, no scaling is applied. The whole of the current wl_buffer is
79 used as the source, and the surface size is as defined in
80 wl_surface.attach.
81
82 If the destination size is set, it causes the surface size to become
83 dst_width, dst_height. The source (rectangle) is scaled to exactly
84 this size. This overrides whatever the attached wl_buffer size is,
85 unless the wl_buffer is NULL. If the wl_buffer is NULL, the surface
86 has no content and therefore no size. Otherwise, the size is always
87 at least 1x1 in surface local coordinates.
88
89 If the source rectangle is set, it defines what area of the wl_buffer is
90 taken as the source. If the source rectangle is set and the destination
91 size is not set, then src_width and src_height must be integers, and the
92 surface size becomes the source rectangle size. This results in cropping
93 without scaling. If src_width or src_height are not integers and
94 destination size is not set, the bad_size protocol error is raised when
95 the surface state is applied.
96
97 The coordinate transformations from buffer pixel coordinates up to
98 the surface-local coordinates happen in the following order:
99 1. buffer_transform (wl_surface.set_buffer_transform)
100 2. buffer_scale (wl_surface.set_buffer_scale)
101 3. crop and scale (wp_viewport.set*)
102 This means, that the source rectangle coordinates of crop and scale
103 are given in the coordinates after the buffer transform and scale,
104 i.e. in the coordinates that would be the surface-local coordinates
105 if the crop and scale was not applied.
106
107 If src_x or src_y are negative, the bad_value protocol error is raised.
108 Otherwise, if the source rectangle is partially or completely outside of
109 the non-NULL wl_buffer, then the out_of_buffer protocol error is raised
110 when the surface state is applied. A NULL wl_buffer does not raise the
111 out_of_buffer error.
112
113 If the wl_surface associated with the wp_viewport is destroyed,
114 all wp_viewport requests except 'destroy' raise the protocol error
115 no_surface.
116
117 If the wp_viewport object is destroyed, the crop and scale
118 state is removed from the wl_surface. The change will be applied
119 on the next wl_surface.commit.
120 </description>
121
122 <request name="destroy" type="destructor">
123 <description summary="remove scaling and cropping from the surface">
124 The associated wl_surface's crop and scale state is removed.
125 The change is applied on the next wl_surface.commit.
126 </description>
127 </request>
128
129 <enum name="error">
130 <entry name="bad_value" value="0"
131 summary="negative or zero values in width or height"/>
132 <entry name="bad_size" value="1"
133 summary="destination size is not integer"/>
134 <entry name="out_of_buffer" value="2"
135 summary="source rectangle extends outside of the content area"/>
136 <entry name="no_surface" value="3"
137 summary="the wl_surface was destroyed"/>
138 </enum>
139
140 <request name="set_source">
141 <description summary="set the source rectangle for cropping">
142 Set the source rectangle of the associated wl_surface. See
143 wp_viewport for the description, and relation to the wl_buffer
144 size.
145
146 If all of x, y, width and height are -1.0, the source rectangle is
147 unset instead. Any other set of values where width or height are zero
148 or negative, or x or y are negative, raise the bad_value protocol
149 error.
150
151 The crop and scale state is double-buffered, see wl_surface.commit.
152 </description>
153 <arg name="x" type="fixed" summary="source rectangle x"/>
154 <arg name="y" type="fixed" summary="source rectangle y"/>
155 <arg name="width" type="fixed" summary="source rectangle width"/>
156 <arg name="height" type="fixed" summary="source rectangle height"/>
157 </request>
158
159 <request name="set_destination">
160 <description summary="set the surface size for scaling">
161 Set the destination size of the associated wl_surface. See
162 wp_viewport for the description, and relation to the wl_buffer
163 size.
164
165 If width is -1 and height is -1, the destination size is unset
166 instead. Any other pair of values for width and height that
167 contains zero or negative values raises the bad_value protocol
168 error.
169
170 The crop and scale state is double-buffered, see wl_surface.commit.
171 </description>
172 <arg name="width" type="int" summary="surface width"/>
173 <arg name="height" type="int" summary="surface height"/>
174 </request>
175 </interface>
176
177</protocol>
