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Core Wayland window system code and protocol
39624020fc
This change breaks the protocol. The current protocol is racy in that updates to surface content and surface state (e.g. damage, input and opaque regions) are not guaranteed to happen at the same time. Due to protocol buffering and handling practices, the issues are very hard to trigger. Committing damage to a surface at arbitrary times makes it hard to track when the wl_buffer is being read by the server, and when it is safe to overwrite (the case of wl_shm with a single buffer reused constantly). This protocol change introduces the concept of double-buffered state. Such state is accumulated and cached in the server, unused, until the final commit request. The surface will receive its new content and apply its new state atomically. A wl_surface.commit request is added to the protocol. This is thought to be more clear, than having wl_surface.attach committing implicitly, and then having another request to commit without attaching, as would be required for a GL app that wants to change e.g. input region without redrawing. When these changes are implemented, clients do not have to worry about ordering damage vs. input region vs. attach vs. ... anymore. Clients set the state in any order they want, and kick it all in with a commit. The interactions between wl_surface.attach, (wl_surface.commit,) wl_buffer.release, and wl_buffer.destroy have been undocumented. Only careful inspection of the compositor code has told when a wl_buffer is free for re-use, especially for wl_shm and wrt. wl_surface.damage. Try to clarify how it all should work, and what happens if the wl_buffer gets destroyed. An additional minor fix: allow NULL argument to wl_surface.set_opaque_region. The wording in the documentation already implied that a nil region is allowed. Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com> |
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| cursor | ||
| doc | ||
| m4 | ||
| protocol | ||
| spec | ||
| src | ||
| tests | ||
| .gitignore | ||
| autogen.sh | ||
| configure.ac | ||
| COPYING | ||
| Makefile.am | ||
| README | ||
| TODO | ||
| wayland-scanner.m4.in | ||
| wayland-scanner.mk | ||
What is Wayland
Wayland is a project to define a protocol for a compositor to talk to
its clients as well as a library implementation of the protocol. The
compositor can be a standalone display server running on Linux kernel
modesetting and evdev input devices, an X applications, or a wayland
client itself. The clients can be traditional applications, X servers
(rootless or fullscreen) or other display servers.
The wayland protocol is essentially only about input handling and
buffer management. The compositor receives input events and forwards
them to the relevant client. The clients creates buffers and renders
into them and notifies the compositor when it needs to redraw. The
protocol also handles drag and drop, selections, window management and
other interactions that must go through the compositor. However, the
protocol does not handle rendering, which is one of the features that
makes wayland so simple. All clients are expected to handle rendering
themselves, typically through cairo or OpenGL.
The weston compositor is a reference implementation of a wayland
compositor and the weston repository also includes a few example
clients clients.
Building the wayland libraries is fairly simple, aside from libffi,
they don't have many dependencies:
$ git clone git://anongit.freedesktop.org/wayland/wayland
$ cd wayland
$ ./autogen.sh --prefix=PREFIX
$ make
$ make install
where PREFIX is where you want to install the libraries. See
http://wayland.freedesktop.org for more complete build instructions
for wayland, weston, xwayland and various toolkits.