Tcell is a Go package that provides a cell based view for text terminals, like XTerm. It was inspired by termbox, but includes many additional improvements.
This is version 2 of Tcell. There are breaking changes relative to version 1.
Version 1.x remains available using the import
mouse demo - included mouse test (screenshot)
gomatrix - converted from Termbox
micro - lightweight text editor with syntax-highlighting and themes
godu - simple golang utility helping to discover large files/folders.
tview - rich interactive widgets for terminal UIs
awesome gocui - Go Console User Interface
gomandelbrot - Mandelbrot!
WTF- Personal information dashboard for your terminal
go-life - Conway’s Game of Life.
gowid - compositional widgets for terminal UIs, inspired by urwid
termshark - a terminal UI for tshark, inspired by Wireshark, built on gowid
go-tetris - Go Tetris with AI option
fzf - A command-line fuzzy finder
ascii-fluid - A terminal based ASCII fluid simulation controlled by webcam
cbind - Provides key event encoding, decoding and handling
tpong - The old-school Pong remade in terminal
aerc - An email client for your terminal.
tblogs - A terminal based development blogs reader
spinc - An irssi inspired terminal chat application for Cisco Spark/WebEx
gorss - A RSS/Atom feed reader for your terminal
memoryalike - A game where you have to memorize runes and hit their respective keys
lf - Terminal file manager
gokeybr - program that helps to deliberately practice your typing.
gonano - CLI test editor
uchess - A UCI chess client for your terminal
min - A Gemini browser
https://github.com/noborus/ov - Terminal pager
Pure Go Terminfo Database
Tcell includes a full parser and expander for terminfo capability strings, so that it can avoid hard coding escape strings for formatting. It also favors portability, and includes support for all POSIX systems.
The database is also flexible & extensible, and can modified by either running a program to build the entire database, or an entry for just a single terminal.
Tcell is portable to a wide variety of systems, and is pure Go, without any need for CGO. Tcell is believed to work with mainstream systems officially supported by golang.
No Async IO
Tcell is able to operate without requiring
SIGIO signals (unlike termbox),
or asynchronous I/O, and can instead use standard Go file
objects and Go routines.
This means it should be safe, especially for
use with programs that use exec, or otherwise need to manipulate the
This model is also much closer to idiomatic Go, leading
to fewer surprises.
Rich Unicode & non-Unicode support
Tcell includes enhanced support for Unicode, including wide characters and combining characters, provided your terminal can support them. Note that Windows terminals generally don’t support the full Unicode repertoire.
It will also convert to and from Unicode locales, so that the program can work with UTF-8 internally, and get reasonable output in other locales. Tcell tries hard to convert to native characters on both input and output, and on output Tcell even makes use of the alternate character set to facilitate drawing certain characters.
More Function Keys
Tcell also has richer support for a larger number of special keys that some terminals can send.
Better Color Handling
Tcell will respect your terminal’s color space as specified within your terminfo entries, so that for example attempts to emit color sequences on VT100 terminals won’t result in unintended consequences.
In legacy Windows mode, Tcell supports 16 colors, bold, dim, and reverse, instead of just termbox’s 8 colors with reverse. (Note that there is some conflation with bold/dim and colors.) Modern Windows 10 can benefit from much richer colors however.
Tcell maps 16 colors down to 8, for terminals that need it. (The upper 8 colors are just brighter versions of the lower 8.)
Better Mouse Support
Tcell supports enhanced mouse tracking mode, so your application can receive regular mouse motion events, and wheel events, if your terminal supports it.
(Note: The Windows 10 Terminal application suffers from a flaw in this regard, and does not support mouse interaction. The stock Windows 10 console host fired up with cmd.exe or PowerShell works fine however.)
A compatibility layer for termbox is provided in the
To use it, try importing
Most termbox-go programs will probably work without further modification.
Working With Unicode
Internally Tcell uses UTF-8, just like Go.
However, Tcell understands how to
convert to and from other character sets, using the capabilities of
Your application must supply
them, as the full set of the most common ones bloats the program by about 2MB.
If you’re lazy, and want them all anyway, see the
Wide & Combining Characters
SetContent() API takes a primary rune, and an optional list of combining runes.
If any of the runes is a wide (East Asian) rune occupying two cells,
then the library will skip output from the following cell, but care must be
taken in the application to avoid explicitly attempting to set content in the
next cell, otherwise the results are undefined. (Normally wide character
is displayed, and the other character is not; do not depend on that behavior.)
Older terminal applications (especially on systems like Windows 8) lack support for advanced Unicode, and thus may not fare well.
Tcell assumes the ANSI/XTerm color model, including the 256 color map that
XTerm uses when it supports 256 colors. The terminfo guidance will be
honored, with respect to the number of colors supported. Also, only
terminals which expose ANSI style
setab will support color;
if you have a color terminal that only has
setb, please submit
a ticket; it wouldn’t be hard to add that if there is need.
Tcell supports true color! (That is, if your terminal can support it, Tcell can accurately display 24-bit color.)
|Technically the approach of using 24-bit RGB values for color is more accurately described as "direct color", but most people use the term "true color", and so we follow the (inaccurate) common convention.|
There are a few ways you can enable (or disable) true color.
For many terminals, we can detect it automatically if your terminal includes the
Tccapabilities (or rather it did when the database was updated.)
You can force this one by setting the
COLORTERMenvironment variable to "24-bit", "truecolor" or "24bit". This is the same method used by most other terminal applications that support 24-bit color.
If you set your
TERMenvironment variable to a value with the suffix
-truecolorthen 24-bit color compatible with XTerm will be assumed (and the terminal will otherwise use the same escape sequences as the base terminal definition.)
|This feature is for compatibility with older Tcell versions. It is recommended to use one of other methods instead.|
You can disable 24-bit color by setting
TCELL_TRUECOLOR=disablein your environment.
When using TrueColor, programs will display the colors that the programmer intended, overriding any “themes” you may have set in your terminal emulator. (For some cases, accurate color fidelity is more important than respecting themes. For other cases, such as typical text apps that only use a few colors, its more desirable to respect the themes that the user has established.)
Reasonable attempts have been made to minimize sending data to terminals, avoiding repeated sequences or drawing the same cell on refresh updates.
(Not relevant for Windows users.)
The Terminfo implementation operates with a built-in database.
This should satisfy most users. However, it can also (on systems
with ncurses installed), dynamically parse the output from
for terminals it does not already know about.
terminfo/ directory for more information about generating
new entries for the built-in database.
Tcell requires that the terminal support the
cup mode of cursor addressing.
Ancient terminals without the ability to position the cursor directly
are not supported.
This is unlikely to be a problem; such terminals have not been mass-produced
since the early 1970s.
Mouse support is detected via the
kmous terminfo variable, however,
enablement/disablement and decoding mouse events is done using hard coded
sequences based on the XTerm X11 model. As of this writing all popular
terminals with mouse tracking support this model. (Full terminfo support
is not possible as terminfo sequences are not defined.)
On Windows, the mouse works normally.
Mouse wheel buttons on various terminals are known to work, but the support in terminal emulators, as well as support for various buttons and live mouse tracking, varies widely. Modern xterm, macOS Terminal, and iTerm all work well.
Terminals that appear to support the XTerm mouse model also can support
bracketed paste, for applications that opt-in. See
EnablePaste() for details.
There is a
SimulationScreen, that can be used to simulate a real screen
for automated testing. The supplied tests do this. The simulation contains
event delivery, screen resizing support, and capabilities to inject events
and examine “physical” screen contents.
POSIX (Linux, FreeBSD, macOS, Solaris, etc.)
Everything works using pure Go on mainstream platforms. Some more esoteric platforms (e.g. AIX) may need to be added. Pull requests are welcome!
Windows console mode applications are supported.
Modern console applications like ConEmu and the Windows 10 terminal, support all the good features (resize, mouse tracking, etc.)
Plan9, WASM, and others
These platforms won’t work, but compilation stubs are supplied
for folks that want to include parts of this in software for those
platforms. The Simulation screen works, but as Tcell doesn’t know how to
allocate a real screen object on those platforms,
NewScreen() will fail.
If anyone has wisdom about how to improve support for these, please let me know. PRs are especially welcome.
Tcell is absolutely free, but if you want to obtain commercial, professional support, there are options.
Tidelift subscriptions include support for Tcell, as well as many other open source packages.
Staysail Systems offers direct support, and custom development around Tcell on an hourly basis.