Copyright © 2013-2014 Collabora, Ltd. Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of the copyright holders not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. The copyright holders make no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty. THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 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. 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. 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. 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 the surface. They indicate how many pixels to remove from the surface size from the left and the top. In other words, they are 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. The associated wl_surface's crop and scale state is removed. The change is applied on the next wl_surface.commit. 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. 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. 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.