A fast, lightweight and minimalistic Wayland terminal emulator
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Lennard Hofmann 6b889564f7 Add logo, fixes #27 5 months ago
.builds ci: alpine: add missing dependencies: pixman + libxkbcommon 7 months ago
completions completions: zsh: footclient: add --hold 6 months ago
doc doc: benchmark: move alacritty-unicode-random text from footnote to separate chapter 5 months ago
icons Add logo, fixes #27 5 months ago
scripts scripts: benchmarking utility script 5 months ago
themes themes: add a couple of color themes 7 months ago
.gitignore fcft/tllist: remove git submodules 10 months ago
.gitlab-ci.yml ci: checkout/clone (doh!) 10 months ago
.gitmodules fcft/tllist: remove git submodules 10 months ago
CHANGELOG.md term: reset: set title to the user configured title, not "foot" 5 months ago
LICENSE add license 1 year ago
PKGBUILD PKGBUILD: works on aarch64 too 5 months ago
README.md readme: fix mastodon link 5 months ago
async.c async: add async_write(), a write primitive to write to a NONBLOCK:ing FD 1 year ago
async.h async: add async_write(), a write primitive to write to a NONBLOCK:ing FD 1 year ago
base64.c base64: implement encode() 1 year ago
base64.h base64: implement encode() 1 year ago
client.c client/server: implement '--hold' in footclient 6 months ago
commands.c scrolling: fix crash when offset was exactly at the wrap-around 6 months ago
commands.h scrollback: initial support for mouse scrolling 1 year ago
config.c util.h: new header file defining commonly used macros 6 months ago
config.h conf: add 'title' conf option and --title command line option 7 months ago
csi.c csi: \E[3J: reset render.last_cursor.row if necessary 5 months ago
csi.h performance improvements 1 year ago
dcs.c sixel: initial support 9 months ago
dcs.h dcs: initial handling of DCS in general 10 months ago
fdm.c fdm: fix log message 10 months ago
fdm.h fdm: add hook priorities 10 months ago
foot-server.desktop Add logo, fixes #27 5 months ago
foot.desktop Add logo, fixes #27 5 months ago
foot.info terminfo: put 'cvvis' on a separate line 6 months ago
footrc conf: rename 'startup-mode' to 'initial-window-mode' 8 months ago
generate-version.sh generate-version: check for .git directory in *src* dir 8 months ago
grid.c grid: swap_row: remove unused parameter 'initialize' 6 months ago
grid.h grid: swap_row: remove unused parameter 'initialize' 6 months ago
input.c selection: don't automatically no-op operations if selection isn't enabled 6 months ago
input.h search: replace hard-coded key bindings with "user configurable" ones 8 months ago
keymap.h keymap: remove trailing whitespaces 7 months ago
log.c log: always log file:lineno 9 months ago
log.h main: add --print-pid=FILE|FD 9 months ago
main.c main: log architecture at startup 5 months ago
meson.build Add logo, fixes #27 5 months ago
misc.c selection: break out isword() to a new file 11 months ago
misc.h selection: break out isword() to a new file 11 months ago
osc.c osc: set color: update both grids, but exclude scrollback 5 months ago
osc.h ocs: renamed parameter size -> required_size in osc_ensure_size() 1 year ago
quirks.c util.h: new header file defining commonly used macros 6 months ago
quirks.h quirks: add KDE quirk: surface must be damaged *after* being attached 8 months ago
reaper.c reaper: disable debug logging 6 months ago
reaper.h reaper: new module, uses a signalfd to wait() on child processes 6 months ago
render.c render: sixel: use pixman_image_composite32() 5 months ago
render.h render: pace title updates 8 months ago
search.c util.h: new header file defining commonly used macros 6 months ago
search.h search: add support for user configurable key bindings 8 months ago
selection.c selection: fix typo when extending selection to cover double-width character 5 months ago
selection.h selection: handle viewport wrap around correctly 6 months ago
server.c client/server: implement '--hold' in footclient 6 months ago
server.h term: don't double fork new terminal windows 6 months ago
shm.c render: re-write cell clipping to use pixman destination clipping 5 months ago
shm.h render: re-write cell clipping to use pixman destination clipping 5 months ago
sixel-hls.c sixel: add HLS color format support 9 months ago
sixel-hls.h sixel: add HLS color format support 9 months ago
sixel.c sixel: if the client has specified a size, do not change that 5 months ago
sixel.h sixel: do not reset palette after each image 5 months ago
slave.c slave: set IUTF8 6 months ago
slave.h slave: prefix argv[0] with a '-' when spawning a login-shell 9 months ago
terminal.c term: reset: set title to the user configured title, not "foot" 5 months ago
terminal.h sixel: if the client has specified a size, do not change that 5 months ago
tokenize.c slave: break out command line tokenizer 1 year ago
tokenize.h slave: break out command line tokenizer 1 year ago
util.h util: thrd_err_as_string: fix alignment 6 months ago
vt.c unicode combining: don't log overflow errors unless LOG_ENABLE_DBG == 1 5 months ago
vt.h Rename: vt_to_slave() -> term_to_slave() 1 year ago
wayland.c wayland: force-trigger a resize on 'configured' event 6 months ago
wayland.h wayland: handle outputs disappearing 7 months ago

README.md

foot

The fast, lightweight and minimalistic Wayland terminal emulator.

Index

  1. Features
  2. Why the name ‘foot’?
  3. Fonts
  4. Shortcuts
    1. Keyboard
      1. Normal mode
      2. Scrollback search
    2. Mouse
  5. Server (daemon) mode
  6. Alt/meta
  7. Backspace
  8. DPI and font size
  9. Supported OSCs
  10. Requirements
    1. Running
    2. Building
  11. Installing
    1. Arch Linux
    2. Other
      1. Setup
      2. Release build
        1. Profile Guided Optimization
      3. Debug build
      4. Running the new build
  12. Bugs
  13. Mastodon

Features

  • Fast (see benchmarks)

  • Lightweight, in dependencies, on-disk and in-memory

  • Wayland native

  • DE agnostic

  • User configurable font fallback

  • On-the-fly font resize

  • On-the-fly DPI font size adjustment

  • Scrollback search

  • Color emoji support

  • Server/daemon mode (one master process, many windows)

  • Synchronized Updates support

  • Sixel image support

    wow

Why the name ‘foot’?

I’m bad at names. Most of my projects usually start out as foo something (for example, yambar was f00bar for a while).

So why foot?

foo terminalfootermfoot

Pretty bad, I know.

As a side note, if you pronounce the foo part of foot the same way you pronounce foobar, then foot sounds a lot like the Swedish word fot, which incidentally means (you guessed it) foot.

Fonts

foot supports all fonts that can be loaded by freetype, including bitmap fonts and color emoji fonts.

Foot uses fontconfig to locate and configure the font(s) to use. Since fontconfig’s fallback mechanism is imperfect, especially for monospace fonts (it doesn’t prefer monospace fonts even though the requested font is one), foot allows you, the user, to configure the fallback fonts to use.

This also means you can configure each fallback font individually; you want that fallback font to use this size, and you want that other fallback font to be italic? No problem!

If a glyph cannot be found in any of the user configured fallback fonts, then fontconfig’s list is used.

Shortcuts

These are the default shortcuts. See man 5 foot and the example footrc to see how these can be changed.

Keyboard

Normal mode

shift+page up/page down
Scroll up/down in history
ctrl+shift+c
Copy selected text to the clipboard
ctrl+shift+v
Paste from clipboard
ctrl+shift+r
Start a scrollback search
ctrl++, ctrl+=
Increase font size by 0,5pt
ctrl+-
Decrease font size by 0,5pt
ctrl+0
Reset font size
ctrl+shift+n
Spawn a new terminal. If the shell has been configured to emit the OSC 7 escape sequence, the new terminal will start in the current working directory.
ctrl+r
Search backward for next match
ctrl+s
Search forward for next match
ctrl+w
Extend current selection (and thus the search criteria) to the end of the word, or the next word if currently at a word separating character.
ctrl+shift+w
Same as ctrl+w, except that the only word separating characters are whitespace characters.
escape, ctrl+g
Cancel the search
return
Finish the search and copy the current match to the primary selection

Mouse

left - single-click
Drag to select; when released, the selected text is copied to the primary selection. This feature is disabled when client has enabled mouse tracking.
Holding shift enables selection in mouse tracking enabled clients.
Holding ctrl will create a block selection.
left - double-click
Selects the word (separated by spaces, period, comma, parenthesis etc) under the pointer. Hold ctrl to select everything under the pointer up to, and until, the next space characters.
left - triple-click
Selects the entire row
middle
Paste from primary selection
right
Extend current selection
wheel
Scroll up/down in history

Server (daemon) mode

When run normally, foot is a single-window application; if you want another window, start another foot process.

However, foot can also be run in a server mode. In this mode, one process hosts multiple windows. Note that this is nothing like tabs. When first started in server mode, no windows are available.

You open new windows by running footclient. This is a small process that instructs the foot server to open a new terminal window. The client process remains running until the terminal window is closed. The exit value of the client process is that of the shell that was running in the terminal window.

The point of this mode is a) reduced memory footprint - all terminal windows will share fonts and glyph cache, and b) reduced startup time - loading fonts and populating the glyph cache takes time, but in server mode it only happens once.

The downside is a performance penalty; all windows’ input and output are multiplexed in the same thread (but each window will have its own set of rendering threads). This means that if one window is very busy with, for example, producing output, then other windows will suffer.

And of course, should the server process crash, all windows will be gone.

Typical usage would be to start the server process (foot --server) when starting your Wayland compositor (i.e. logging in to your desktop), and then run footclient instead of foot whenever you want to launch a new terminal.

Alt/meta

By default, foot prefixes Meta characters with ESC. This corresponds to XTerm’s metaSendsEscape option set to true.

This can be disabled programatically with \E[?1036l (and enabled again with \E[?1036h).

When disabled, foot will instead set the 8:th bit of meta character and then UTF-8 encode it. This corresponds to XTerm’s eightBitMeta option set to true.

This can also be disabled programatically with rmm (reset meta mode, \E[?1034l), and enabled again with smm (set meta mode, \E[?1034h).

Backspace

Foot transmits DEL (^?) on backspace. This corresponds to XTerm’s backarrowKey option set to false, and to DECBKM being reset.

To instead transmit BS (^H), press ctrl+backspace.

Note that foot does not implement DECBKM, and that the behavior described above cannot be changed.

Finally, pressing alt will prefix the transmitted byte with ESC.

DPI and font size

Font sizes are apparently a complex thing. Many applications use a fixed DPI of 96. They may also multiply it with the monitor’s scale factor.

This results in fonts with different physical sizes (i.e. if measured by a ruler) when rendered on screens with different DPI values. Even if the configured font size is the same.

This is not how it is meant to be. Fonts are measured in point sizes for a reason; a given point size should have the same height on all mediums, be it printers or monitors, regardless of their DPI.

Foot will always use the monitor’s physical DPI value. Scale factors are irrelevant (well, they affect e.g. padding, but not the font size). This means the glyphs rendered by foot should always have the same physical height, regardless of monitor.

Foot will re-size the fonts on-the-fly when the window is moved between screens with different DPIs values. If the window covers multiple screens, with different DPIs, the highest DPI will be used.

Tip: QT applications can be configured to work this way too, by exporting the environment variable QT_WAYLAND_FORCE_DPI=physical.

Note: if you configure pixelsize, rather than size, then DPI changes will not change the font size. Pixels are always pixels.

Supported OSCs

OSC, Operating System Command, are escape sequences that interacts with the terminal emulator itself. Foot implements the following OSCs:

  • OSC 0 - change window icon + title (but only title is actually supported)
  • OSC 2 - change window title
  • OSC 4 - change color palette
  • OSC 7 - report CWD
  • OSC 10 - change (default) foreground color
  • OSC 11 - change (default) background color
  • OSC 12 - change cursor color
  • OSC 52 - copy/paste clipboard data
  • OSC 104 - reset color palette
  • OSC 110 - reset default foreground color
  • OSC 111 - reset default background color
  • OSC 112 - reset cursor color
  • OSC 555 - flash screen (foot specific)

Requirements

Running

  • fontconfig
  • freetype
  • pixman
  • wayland (client and cursor libraries)
  • xkbcommon
  • tllist 1
  • fcft 1

Building

In addition to the dev variant of the packages above, you need:

  • meson
  • ninja
  • wayland protocols
  • ncurses
  • scdoc

A note on compilers; in general, foot runs much faster when compiled with gcc instead of clang. A profile-guided gcc build can be more than twice as fast as a clang build.

Note GCC 10.1 has a performance regression that severely affects foot when doing PGO builds and building with -O2; it is about 30-40% slower compared to GCC 9.3.

The work around is simple: make sure you build with -O3. This is the default with meson --buildtype=release, but e.g. makepkg can override it (makepkg uses -O2 by default).

Installing

foot makes use of a couple of libraries I have developed: tllist and fcft. As such, they will most likely not have been installed already. You can either install them as system libraries, or you can build them as subprojects in foot.

When building foot, they will first be searched for as system libraries. If found, foot will link dynamically against them.

If not found, they will be searched for as subprojects. In this case you need to create the subprojects directory and clone https://codeberg.org/dnkl/fcft.git and https://codeberg.org/dnkl/tllist.git (see Other below).

Arch Linux

Install from AUR:

Or use makepkg to build the bundled PKGBUILD (run makepkg in the source root directory).

Unlike the AUR packages, the bundled PKGBUILD requires tllist and fcft to be installed as system libraries. If you do not want this, please edit the PKGBUILD file, or install manually (see Other below).

Note that it will do a profiling-guided build, and that this requires a running wayland session since it needs to run an intermediate build of foot.

Other

Foot uses meson. If you are unfamiliar with it, the official tutorial might be a good starting point.

I also recommend taking a look at the bundled Arch PKGBUILD file, to see how it builds foot. Especially so if you intend to install a release build of foot, in which case you might be interested in the compiler flags used there.

Setup

If you have not installed tllist and fcft as system libraries, clone them into the subprojects directory:

mkdir -p subprojects
pushd subprojects
git clone https://codeberg.org/dnkl/tllist.git
git clone https://codeberg.org/dnkl/fcft.git
popd

To build, first, create a build directory, and switch to it:

mkdir -p bld/release && cd bld/release

Release build

export CFLAGS+="-O3 -march=native -fno-plt"
meson --buildtype=release --prefix=/usr -Db_lto=true

For performance reasons, I strongly recommend doing a PGO (Profile Guided Optimization) build. This requires a running Wayland session since we will be executing an intermediate build of foot.

If you do not want this, just build:

ninja

and then skip to Running the new build.

For packagers: normally, you would configure compiler flags using -Dc_args. This however “overwrites” CFLAGS. makepkg from Arch, for example, uses CFLAGS to specify the default set of flags.

Thus, we do export CFLAGS+="..." to at least not throw away those flags.

When packaging, you may want to use the default CFLAGS only, but note this: foot is a performance critical application that relies on compiler optimizations to perform well.

In particular, with GCC 10.1, it is very important -O3 is used (and not e.g. -O2) when doing a PGO build.

Profile Guided Optimization

First, make sure you have configured a release build directory, but:

If using Clang, make sure to add -Wno-ignored-optimization-argument -Wno-profile-instr-out-of-date to CFLAGS.

If using GCC, make sure to add -Wno-missing-profile to CFLAGS.

Then, tell meson we want to generate profile data, and build:

meson configure -Db_pgo=generate
ninja

Next, we need to execute the intermediate build of foot, and run a payload inside it that will exercise the performance critical code paths. To do this, we will use the script scripts/generate-alt-random-writes.py:

foot_tmp_file=$(mktemp)
./foot --config=/dev/null --term=xterm sh -c "<path-to-generate-alt-ranodm-writes.py> --scroll --scroll-region --colors-regular --colors-bright --colors-rgb ${foot_tmp_file} && cat ${foot_tmp_file}"
rm ${foot_tmp_file}

You should see a foot window open up, with random colored text. The window should close after ~1-2s.

If using Clang, now do (this requires llvm to have been installed):

llvm-profdata merge default_*profraw --output=default.profdata

Next, tell meson to use the profile data we just generated, and rebuild:

meson configure -Db_pgo=use
ninja

Continue reading in Running the new build

Debug build

meson --buildtype=debug ../..
ninja

Running the new build

You can now run it directly from the build directory:

./foot

But note that it will default to TERM=foot, and that this terminfo has not been installed yet. However, most things should work with the xterm-256color terminfo:

./foot --term xterm-256color

But, I recommend you install the foot and foot-direct terminfo files. You can either copy them manually (typically to /usr/share/terminfo/f - but this is dependens on the distro), or just install everything:

ninja install

BUGS

Please report bugs to https://codeberg.org/dnkl/foot/issues

The report should contain the following:

  • Which Wayland compositor (and version) you are running
  • Foot version (foot --version)
  • Log output from foot (start foot from another terminal)
  • If reporting a crash, please try to provide a bt full backtrace with symbols (i.e. use a debug build)
  • Steps to reproduce. The more details the better

Mastodon

Every now and then I post foot related updates on @dnkl@linuxrocks.online


  1. can also be built as subprojects, in which case they are statically linked. ↩︎