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.

A brief, and still somewhat rough, tutorial is available.

A number of example are posted up on our Gallery. That's a wiki, and please do submit updates if you have something you want to showcase.

Tcell is portable to a wide variety of systems, and is pure Go, without any need for CGO. Tcell works with mainstream systems officially supported by golang.

Following the Go support policy, Tcell officially only supports the current ("stable") version of go, and the version immediately prior ("oldstable"). This policy is necessary to make sure that we can update dependencies to pick up security fixes and new features, and it allows us to adopt changes (such as library and language features) that are only supported in newer versions of Go.

Tcell includes enhanced support for Unicode, including wide characters and grapheme clusters, provided your terminal can support them.

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. On output Tcell even makes use of the alternate character set to facilitate drawing certain characters.

Tcell also has richer support for a larger number of special keys that some terminals can send. On modern terminal emulators we can also support a rich set of modifiers, and can discriminate between e.g. CTRL-I and TAB. (This does require the terminal emulator to support one of the modern keyboard protocols.)

Tcell supports enhanced mouse tracking mode, so your application can receive regular mouse motion events, click-drag, and wheel events, if your terminal supports it.

Internally Tcell uses UTF-8, just like Go. However, Tcell understands how to convert to and from other character sets, using the capabilities of the golang.org/x/text/encoding packages. Your application must supply them, as the full set of the most common ones bloats the program by about 2 MB. If you're lazy, and want them all anyway, see the encoding sub-directory.

The Put() API takes a string, which should be legal UTF-8, and displays the first grapheme cluster (which may composed of multiple runes). It returns the actual width displayed, which can be used to advance the column positiion for the next display grapheme. Alternatively, PutStr() or PutStrStyled() can be used to display a single line of text (which will be clipped at the edge of the screen).

If a second character is displayed immediately in the cell adjacent to a wide character (offset by one instead of by two), then the results are undefined.

Tcell assumes the ANSI/XTerm color palette for up to 256 colors, although terminals such as legacy ANSI terminals may only support 8 colors.

Tcell supports 24-bit color! (That is, if your terminal can support it.)

There are a few ways you can enable (or disable) 24-bit color.

• You can force this one by setting the COLORTERM environment variable to truecolor. This environment variable is frequently set by terminal emulators that support 24-bit color.

• On Windows, 24-bit color support is assumed. (All modern Windows terminal emulators support it.)

• If you set your TERM environment variable to a value with the suffix -truecolor or -direct, then 24-bit color compatible with XTerm and ECMA-48 will be assumed.

• You can disable 24-bit color by setting TCELL_TRUECOLOR=disable in your environment.

When using 24-bit color, programs will display the colors that the programmer intended, overriding any "themes" the user may have set in their 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.

Mouse tracking, buttons, and even wheel mice are supported on most terminal emulators, as well as Windows.

Terminals that support support it, can use bracketed paste. See EnablePaste() for details.

There are a number of changes in Tcell version 3, which break compatibility with version 2 and version 1.

Your application will almost certainly need some minor updates to work with version 3.

Please see the CHANGESv3 document for a list.

Everything works using pure Go on mainstream platforms. Esoteric platforms (e.g. zOS or AIX) are supported on a best-effort only basis. Pull requests to fix any issues found are welcome!

Modern Windows is supported. Please see the README-windows document for much more detailed information.

WASM is supported, but needs additional setup detailed in README-wasm.

Plan 9 is supported on a best-effort basis. Please see the README-plan document for more information.

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 Inc. offers direct support, and custom development around Tcell on an hourly basis.