I'd say we should split the cropping and scaling request into two. Specifying a scaling with a NULL buffer should still set the surface size, so we can have surfaces with only an input region.
I don't see a way to disable scaling and cropping, could passing 0 as width and height do that? On Tue, Apr 30, 2013 at 2:33 PM, Pekka Paalanen <ppaala...@gmail.com> wrote: > Hi all, > > below is my first draft for a wl_surface scaling and cropping > extension. I called it wl_scaler in the lack of a better name. It is > designed similarly to the other wl_surface extensions wl_shell_surface > and wl_subsurface. > > There probably isn't any interesting details to debate, right? ;-) > > I'd like to have a better name for it, and you might want the set > request split into two or three, or not, but otherwise I'm quite > satisfied with it. I tried to take into account all existing protocol > that interacts with this. > > Comments? Is the language clear? > > > Thanks, > pq > > > <?xml version="1.0" encoding="UTF-8"?> > <protocol name="scaler"> > > <copyright> > Copyright © 2013 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. > </copyright> > > <interface name="wl_scaler" version="1"> > <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 1:1 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_surface_scaler objects included. > </description> > </request> > > <enum name="error"> > <entry name="scaler_exists" value="0" > summary="the surface already has a scaler object associated"/> > </enum> > > <request name="get_surface_scaler"> > <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_surface_scaler object associated, the scaler_exists > protocol error is raised. > </description> > > <arg name="id" type="new_id" interface="wl_surface_scaler" > summary="the new scaler interface id"/> > <arg name="surface" type="object" interface="wl_surface" > summary="the surface"/> > </request> > </interface> > > <interface name="wl_surface_scaler" version="1"> > <description summary="crop and scale interface to a wl_surface"> > An additional interface to a wl_surface object, allowing 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. > > Before the first set request, the wl_surface still behaves as if > there was no crop and scale state. That is, no scaling is applied, > and the surface size is the buffer size. > > On compositing, source rectangle coordinates are evaluated after > wl_surface.set_buffer_transform is evaluated. This means that > changing the buffer transform and correspondingly the client > rendering does not require sending new source rectangle > coordinates to keep the exact same image source rectangle. In > other words, the source rectangle is given in the > not-scaled-and-cropped surface coordinates, not buffer data > coordinates. > > The crop and scale state causes the surface size to become > dst_width, dst_height. This overrides whatever the attached > wl_buffer size is, unless the wl_buffer is NULL. > > The surface-local coordinate system is tied to the space of > dst_width and dst_height. That is, surface-local coordinates are > relative to the scaled and cropped surface, not the wl_buffer > providing the content. > > If the source rectangle is partially or completely outside of the > wl_buffer, then the surface contents are undefined, 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_surface_scaler is > destroyed, the wl_surface_scaler object becomes inert. > > If the wl_surface_scaler 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 values in width or height"/> > </enum> > > <request name="set"> > <description summary="set the crop and scale state"> > Set the crop and scale state of the associated wl_surface. See > wl_surface_scaler for the description, and relation to the > wl_buffer size. > > If any of src_width, src_height, dst_width, and dst_height is > negative, the bad_value protocol error is raised. > </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> > > </interface> > </protocol> > > > _______________________________________________ > wayland-devel mailing list > wayland-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/wayland-devel >
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