Difference between revisions of "Wayland"

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[http://wayland.freedesktop.org/ Wayland] is a protocol for a [[wikipedia:Compositing window manager|compositing window manager]] to talk to its clients, as well as a library implementing the protocol. Some Linux desktop environments, like [[GNOME]] and [[KDE]], support Wayland. There is also a compositor reference implementation called Weston. [https://wayland.freedesktop.org/xserver.html XWayland] implements a compatibility layer to seamlessly run legacy [[X11]] applications on Wayland.
+
[http://wayland.freedesktop.org/ Wayland] is a protocol for a [[wikipedia:Compositing window manager|compositing window manager]] to talk to its clients, as well as a library implementing the protocol. It is supported on some Linux desktop environments like [[GNOME]] and [[KDE]]. There is also a compositor reference implementation called Weston. [https://wayland.freedesktop.org/xserver.html XWayland] implements a compatibility layer to seamlessly run legacy [[X11]] applications on Wayland.
  
 
== Requirements ==
 
== Requirements ==

Revision as of 06:28, 8 August 2018

Wayland is a protocol for a compositing window manager to talk to its clients, as well as a library implementing the protocol. It is supported on some Linux desktop environments like GNOME and KDE. There is also a compositor reference implementation called Weston. XWayland implements a compatibility layer to seamlessly run legacy X11 applications on Wayland.

Requirements

Most Wayland compositors only work on systems using Kernel mode setting.

Wayland by itself does not provide a graphical environment; for this you also need a compositor such as #Weston or Sway, or a desktop environment that includes a compositor like GNOME or KDE.

Buffer API support

For the GPU driver and Wayland compositor to be compatible they must support the same buffer API. There are two main APIs: GBM and EGLStreams.

Buffer API GPU driver support Wayland compositor support
GBM All except NVIDIA All
EGLStreams NVIDIA GNOME, Grefsen, Sway (will be removed)

Weston

Weston is the reference implementation of a Wayland compositor.

Installation

Install the weston package.

Usage

Tip: Super (windows key) can be changed, see weston.ini
Keyboard Shortcuts
Cmd Action
Ctrl+Alt+Backspace Quit Weston
Super+Scroll (or PageUp/PageDown) Zoom in/out of desktop
Super+Tab Switch windows
Super+LMB Move Window
Super+MMB Rotate Window !
Super+RMB Resize Window
Super+Alt+Scroll Change window opacity
Super+K Force Kill Active Window
Super+KeyUp/KeyDown Switch Prev/Next Workspace
Super+Shift+KeyUp/KeyDown Grab Current Window and Switch Workspace
Super+Fn Switch to Workspace n
Super+S Take a screenshot
Super+R Record a screencast.

Now that Wayland and its requirements are installed you should be ready to test it out.

To launch Weston natively (from a TTY) or to run Weston inside a running X session:

$ weston

Then within Weston, you can run the demos. To launch a terminal emulator:

$ weston-terminal

To move flowers around the screen:

$ weston-flower 

To display images:

$ weston-image image1.jpg image2.jpg...

Configuration

Weston's outputs differ slightly from those of xorg.conf Monitors:

$ ls /sys/class/drm
card0
card0-VGA-1
card1
card1-DVI-I-1
card1-HDMI-A-1
card1-VGA-2

card0 is the unused built-in video adapter. The add-on adapter card1 is cabled to one HDMI and one DVI monitor, so the output names are HDMI-A-1 and DVI-I-1.

Following is an example configuration file. See weston.ini(5) for more.

~/.config/weston.ini
[core]
# xwayland support
xwayland=true

[libinput]
enable_tap=true

[shell]
#background-image=/usr/share/backgrounds/gnome/Aqua.jpg
background-type=scale-crop
background-color=0xff000000
#background-color=0xff002244
#panel-color=0x90ff0000
panel-color=0x00ffffff
panel-position=bottom
#clock-format=none
#animation=zoom
#startup-animation=none
close-animation=none
focus-animation=dim-layer
#binding-modifier=ctrl
num-workspaces=6
locking=false

# for cursor themes install xcursor-themes pkg from Extra
#cursor-theme=whiteglass
#cursor-size=24

# tablet options
#lockscreen-icon=/usr/share/icons/gnome/256x256/actions/lock.png
#lockscreen=/usr/share/backgrounds/gnome/Garden.jpg
#homescreen=/usr/share/backgrounds/gnome/Blinds.jpg
#animation=fade

# for Laptop displays
[output]
name=LVDS1
mode=preferred
#mode=1680x1050
#transform=90

#[output]
#name=VGA1
# The following sets the mode with a modeline, you can get modelines for your preffered resolutions using the cvt utility
#mode=173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync
#transform=flipped

#[output]
#name=X1
#mode=1024x768
#transform=flipped-270

# on screen keyboard input method
#[input-method]
#path=/usr/lib/weston/weston-keyboard

[keyboard]
keymap_rules=evdev
#keymap_layout=us,de
#keymap_variant=colemak,
#keymap_options=grp:shifts_toggle
#keymap_options=caps:ctrl_modifier,shift:both_capslock_cancel
repeat-rate=30
repeat-delay=300

# keymap_options from /usr/share/X11/xkb/rules/base.lst
#numlock-on=true

[terminal]
font=monospace
font-size=18

[launcher]
icon=/usr/share/weston/icon_flower.png
path=/usr/bin/weston-flower

[launcher]
icon=/usr/share/icons/gnome/32x32/apps/utilities-terminal.png
path=/usr/bin/weston-terminal --shell=/usr/bin/bash

[launcher]
icon=/usr/share/icons/gnome/32x32/apps/utilities-terminal.png
path=/usr/bin/gnome-terminal

[launcher]
icon=/usr/share/icons/hicolor/32x32/apps/firefox.png
path=MOZ_GTK_TITLEBAR_DECORATION=client /usr/bin/firefox

#[launcher]
#icon=/usr/share/icons/Adwaita/32x32/apps/multimedia-volume-control.png
#path=/usr/bin/st alsamixer -c0

Minimal weston.ini :

~/.config/weston.ini
[core]
xwayland=true

[keyboard]
keymap_layout=gb

[output]
name=LVDS1
mode=1680x1050
transform=90

[launcher]
icon=/usr/share/icons/gnome/24x24/apps/utilities-terminal.png
path=/usr/bin/weston-terminal

[launcher]
icon=/usr/share/icons/hicolor/24x24/apps/firefox.png
path=/usr/bin/firefox


XWayland

Install the xorg-server-xwayland package.

When you want to run an X application from within Weston, it spins up Xwayland to service the request. The following configuration is shown above:

~/.config/weston.ini
[core]
xwayland=true
Note: if X is not already configured you may need to configure a keymap: Keyboard configuration in Xorg

Screencast recording

Weston has build-in screencast recording which can be started and stopped by pressing the Super+r key combination. Screencasts are saved to the file capture.wcap in the current working directory of Weston.

The WCAP format is a lossless video format specific to Weston, which only records the difference in frames. To be able to play the recorded screencast, the WCAP file will need to be converted to a format which a media player can understand. First, convert the capture to the YUV pixel format:

$ wcap-decode capture.wcap --yuv4mpeg2 > capture.y4m

The YUV file can then be transcoded to other formats using FFmpeg.

High DPI displays

For Retina or HiDPI displays, use:

~/.config/weston.ini
[output]
name=...
scale=2

Shell font

Weston uses the default sans-serif font for window title bars, clocks, etc. See Font configuration#Replace or set default fonts for instructions on how to change this font.

Tips and tricks

Window switching

To switch windows with Super+Space instead of Super+Tab use the following patch:

diff --git a/shell.c b/shell.c
index b846e30..ffe5e48 100644
--- a/shell.c
+++ b/shell.c
@@ -4457,7 +4457,7 @@ switcher_key(struct weston_keyboard_grab *grab,
 	struct switcher *switcher = container_of(grab, struct switcher, grab);
 	enum wl_keyboard_key_state state = state_w;
 
-	if (key == KEY_TAB && state == WL_KEYBOARD_KEY_STATE_PRESSED)
+	if (key == KEY_SPACE && state == WL_KEYBOARD_KEY_STATE_PRESSED)
 		switcher_next(switcher);
 }
 
@@ -4949,7 +4949,7 @@ shell_add_bindings(struct weston_compositor *ec, struct desktop_shell *shell)
 		weston_compositor_add_button_binding(ec, BTN_MIDDLE, mod,
 						     rotate_binding, NULL);
 
-	weston_compositor_add_key_binding(ec, KEY_TAB, mod, switcher_binding,
+	weston_compositor_add_key_binding(ec, KEY_SPACE, mod, switcher_binding,
 					  shell);
 	weston_compositor_add_key_binding(ec, KEY_F9, mod, backlight_binding,
 					  ec);

GUI libraries

See details on the official website.

GTK+ 3

The gtk3 package has the Wayland backend enabled. GTK+ will default to the Wayland backend, but it is possible to override it to Xwayland by modifying an environment variable: GDK_BACKEND=x11.

Qt 5

To enable Wayland support in Qt 5, install the qt5-wayland package.

To run a Qt 5 app with the Wayland plugin, use -platform wayland or set the QT_QPA_PLATFORM=wayland-egl environment variable.

Clutter

The Clutter toolkit has a Wayland backend that allows it to run as a Wayland client. The backend is enabled in the clutter package.

To run a Clutter app on Wayland, set CLUTTER_BACKEND=wayland.

SDL2

To run a SDL2 application on Wayland, set SDL_VIDEODRIVER=wayland.

GLFW

To use GLFW with the Wayland backend, install the glfw-wayland package (instead of glfw-x11).

GLEW

To use GLEW with the Wayland backend, install the glew-wayland package (instead of glew).

EFL

EFL has complete Wayland support. To run a EFL application on Wayland, see Wayland project page.

Compositors

Name Type Description
GNOME Stacking See GNOME#Starting.
sway Tiling Sway is an i3-compatible window manager for Wayland. GitHub
Enlightenment Stacking More Info
KDE Plasma Stacking See KDE#Starting Plasma
Orbment Tiling orbment (previously loliwm) is an abandonned tiling WM for Wayland.
Velox Tiling Velox is a simple window manager based on swc. It is inspired by dwm and xmonad.
Orbital Stacking Orbital is a Wayland compositor and shell (more akin to a WM than a DE) using Qt5 and Weston. The goal of the project is to build a simple but flexible and good looking Wayland desktop.
Liri Shell Stacking Liri Shell is the desktop shell for Liri, built using QtQuick and QtCompositor as a compositor for Wayland.
Maynard (Unclear) Maynard is a desktop shell client for Weston based on GTK. It was based on weston-gtk-shell, a project by Tiago Vignatti. Not under development. [1][2]
Motorcar (Unclear) Motorcar is a Wayland compositor to explore 3D windowing using virtual reality.
Way Cooler Tiling way-coolerAUR is a customizable (Lua config files) Wayland compositor written in Rust. Inspired by i3 and awesome.
Maze Compositor Floating 3D Maze Compositor is a 3D Qt based Wayland compositor
Grefsen Floating Grefsen is a Qt/Wayland compositor providing a minimal desktop environment.
Waymonad Tiling Waymonad is a Wayland compositor based on ideas from and inspired by xmonad

Some of installed wayland desktop clients might store information in /usr/share/wayland-sessions/*.desktop files about how to start them in wayland.

Troubleshooting

Running graphical applications as root

See Running GUI apps as root.

Tango-edit-clear.pngThis article or section needs language, wiki syntax or style improvements. See Help:Style for reference.Tango-edit-clear.png

Reason: Many of these subsections should go into a "Known issues" section (i.e., there is no solution currently). Additionally prepending a date is not needed. (Discuss in Talk:Wayland#)

LLVM assertion failure

If you get an LLVM assertion failure, you need to rebuild mesa without Gallium LLVM until this problem is fixed.

This may imply disabling some drivers which require LLVM. You may also try exporting the following, if having problems with hardware drivers:

$ export EGL_DRIVER=/usr/lib/egl/egl_gallium.so

Slow motion, graphical glitches, and crashes

Gnome-shell users may experience display issues when they switch to Wayland from X. One of the root cause might be the CLUTTER_PAINT=disable-clipped-redraws:disable-culling set by yourself for Xorg-based gnome-shell. Just try to remove it from /etc/environment or other rc files to see if everything goes back to normal.

X11 on tty1, Wayland on tty2

(20161209) windows of GNOME applications end up on tty2 no matter where started (GNOME issue 774775)

GNOME Wayland on tty1, Weston on tty2

(20170106) apps started on GNOME with WAYLAND_DISPLAY set to weston make it not respond any more (Wayland issue 99489)

weston-terminal

(20161229) core dump when started on gnome

liteide

(20161229) core dump] on GNOME and Weston.

screen recording

Currently only green-recorderAUR supports screen recording on Wayland (requires a GNOME session).

remote display

Input grabbing in games, remote desktop and VM windows

In contrast to Xorg, Wayland does not allow exclusive input device grabbing, also known as active or explicit grab (e.g. keyboard, mouse), instead, it depends on the Wayland compositor to pass keyboard shortcuts and confine the pointer device to the application window.

This change in input grabbing breaks current applications' behavior, meaning:

  • Hotkey combinations and modifiers will be caught by the compositor and won't be sent to remote desktop and virtual machine windows.
  • The mouse pointer will not be restricted to the application's window which might cause a parallax effect where the location of the mouse pointer inside the window of the virtual machine or remote desktop is displaced from the host's mouse pointer.

Wayland solves this by adding protocol extensions for Wayland and XWayland. Support for these extensions is needed to be added to the Wayland compositors. In the case of native Wayland clients, the used widget toolkits (e.g GTK, QT) needs to support these extensions or the applications themselves if no widget toolkit is being used. In the case of Xorg applications, no changes in the applications or widget toolkits are needed as the XWayland support is enough.

These extensions are already included in wayland-protocols, and supported by xorg-server-xwayland 1.20.

The related extensions are:

Supporting Wayland compositors:

Supporting widget toolkits:

  • GTK since release 3.22.18.

wlroots input inhibitor protocol

Input inhibitor is a Wayland protocol which was defined the by developers of Sway and wlroots and is overlapping Wayland's Compositor shortcuts inhibit protocol.
Sway and wlroots do not support the Compositor shortcuts inhibit and XWayland keyboard grabbing protocols, and least for the latter it seems like they are against adding support for it [3] [4].
No widget toolkit or application is known to support this protocol.

See also