<p align="center">
<img src="https://stuff.charm.sh/termenv.png" width="480" alt="termenv Logo">
<br />
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<br />
<img src="https://github.com/muesli/termenv/raw/master/examples/hello-world/hello-world.png" alt="Example terminal output">
</p>
`termenv` lets you safely use advanced styling options on the terminal. It
gathers information about the terminal environment in terms of its ANSI & color
support and offers you convenient methods to colorize and style your output,
without you having to deal with all kinds of weird ANSI escape sequences and
color conversions.
## Features
- RGB/TrueColor support
- Detects the supported color range of your terminal
- Automatically converts colors to the best matching, available colors
- Terminal theme (light/dark) detection
- Chainable syntax
- Nested styles
## Installation
```bash
go get github.com/muesli/termenv
```
## Usage
```go
output := termenv.NewOutput(os.Stdout)
```
`termenv` queries the terminal's capabilities it is running in, so you can
safely use advanced features, like RGB colors or ANSI styles. `output.Profile`
returns the supported profile:
- `termenv.Ascii` - no ANSI support detected, ASCII only
- `termenv.ANSI` - 16 color ANSI support
- `termenv.ANSI256` - Extended 256 color ANSI support
- `termenv.TrueColor` - RGB/TrueColor support
Alternatively, you can use `termenv.EnvColorProfile` which evaluates the
terminal like `ColorProfile`, but also respects the `NO_COLOR` and
`CLICOLOR_FORCE` environment variables.
You can also query the terminal for its color scheme, so you know whether your
app is running in a light- or dark-themed environment:
```go
// Returns terminal's foreground color
color := output.ForegroundColor()
// Returns terminal's background color
color := output.BackgroundColor()
// Returns whether terminal uses a dark-ish background
darkTheme := output.HasDarkBackground()
```
### Manual Profile Selection
If you don't want to rely on the automatic detection, you can manually select
the profile you want to use:
```go
output := termenv.NewOutput(os.Stdout, termenv.WithProfile(termenv.TrueColor))
```
## Colors
`termenv` supports multiple color profiles: Ascii (black & white only),
ANSI (16 colors), ANSI Extended (256 colors), and TrueColor (24-bit RGB). Colors
will automatically be degraded to the best matching available color in the
desired profile:
`TrueColor` => `ANSI 256 Colors` => `ANSI 16 Colors` => `Ascii`
```go
s := output.String("Hello World")
// Supports hex values
// Will automatically degrade colors on terminals not supporting RGB
s.Foreground(output.Color("#abcdef"))
// but also supports ANSI colors (0-255)
s.Background(output.Color("69"))
// ...or the color.Color interface
s.Foreground(output.FromColor(color.RGBA{255, 128, 0, 255}))
// Combine fore- & background colors
s.Foreground(output.Color("#ffffff")).Background(output.Color("#0000ff"))
// Supports the fmt.Stringer interface
fmt.Println(s)
```
## Styles
You can use a chainable syntax to compose your own styles:
```go
s := output.String("foobar")
// Text styles
s.Bold()
s.Faint()
s.Italic()
s.CrossOut()
s.Underline()
s.Overline()
// Reverse swaps current fore- & background colors
s.Reverse()
// Blinking text
s.Blink()
// Combine multiple options
s.Bold().Underline()
```
## Template Helpers
`termenv` provides a set of helper functions to style your Go templates:
```go
// load template helpers
f := output.TemplateFuncs()
tpl := template.New("tpl").Funcs(f)
// apply bold style in a template
bold := `{{ Bold "Hello World" }}`
// examples for colorized templates
col := `{{ Color "#ff0000" "#0000ff" "Red on Blue" }}`
fg := `{{ Foreground "#ff0000" "Red Foreground" }}`
bg := `{{ Background "#0000ff" "Blue Background" }}`
// wrap styles
wrap := `{{ Bold (Underline "Hello World") }}`
// parse and render
tpl, err = tpl.Parse(bold)
var buf bytes.Buffer
tpl.Execute(&buf, nil)
fmt.Println(&buf)
```
Other available helper functions are: `Faint`, `Italic`, `CrossOut`,
`Underline`, `Overline`, `Reverse`, and `Blink`.
## Positioning
```go
// Move the cursor to a given position
output.MoveCursor(row, column)
// Save the cursor position
output.SaveCursorPosition()
// Restore a saved cursor position
output.RestoreCursorPosition()
// Move the cursor up a given number of lines
output.CursorUp(n)
// Move the cursor down a given number of lines
output.CursorDown(n)
// Move the cursor up a given number of lines
output.CursorForward(n)
// Move the cursor backwards a given number of cells
output.CursorBack(n)
// Move the cursor down a given number of lines and place it at the beginning
// of the line
output.CursorNextLine(n)
// Move the cursor up a given number of lines and place it at the beginning of
// the line
output.CursorPrevLine(n)
```
## Screen
```go
// Reset the terminal to its default style, removing any active styles
output.Reset()
// RestoreScreen restores a previously saved screen state
output.RestoreScreen()
// SaveScreen saves the screen state
output.SaveScreen()
// Switch to the altscreen. The former view can be restored with ExitAltScreen()
output.AltScreen()
// Exit the altscreen and return to the former terminal view
output.ExitAltScreen()
// Clear the visible portion of the terminal
output.ClearScreen()
// Clear the current line
output.ClearLine()
// Clear a given number of lines
output.ClearLines(n)
// Set the scrolling region of the terminal
output.ChangeScrollingRegion(top, bottom)
// Insert the given number of lines at the top of the scrollable region, pushing
// lines below down
output.InsertLines(n)
// Delete the given number of lines, pulling any lines in the scrollable region
// below up
output.DeleteLines(n)
```
## Session
```go
// SetWindowTitle sets the terminal window title
output.SetWindowTitle(title)
// SetForegroundColor sets the default foreground color
output.SetForegroundColor(color)
// SetBackgroundColor sets the default background color
output.SetBackgroundColor(color)
// SetCursorColor sets the cursor color
output.SetCursorColor(color)
// Hide the cursor
output.HideCursor()
// Show the cursor
output.ShowCursor()
// Copy to clipboard
output.Copy(message)
// Trigger notification
output.Notify(title, body)
```
## Mouse
```go
// Enable X10 mouse mode, only button press events are sent
output.EnableMousePress()
// Disable X10 mouse mode
output.DisableMousePress()
// Enable Mouse Tracking mode
output.EnableMouse()
// Disable Mouse Tracking mode
output.DisableMouse()
// Enable Hilite Mouse Tracking mode
output.EnableMouseHilite()
// Disable Hilite Mouse Tracking mode
output.DisableMouseHilite()
// Enable Cell Motion Mouse Tracking mode
output.EnableMouseCellMotion()
// Disable Cell Motion Mouse Tracking mode
output.DisableMouseCellMotion()
// Enable All Motion Mouse mode
output.EnableMouseAllMotion()
// Disable All Motion Mouse mode
output.DisableMouseAllMotion()
```
## Bracketed Paste
```go
// Enables bracketed paste mode
termenv.EnableBracketedPaste()
// Disables bracketed paste mode
termenv.DisableBracketedPaste()
```
## Terminal Feature Support
### Color Support
- 24-bit (RGB): alacritty, foot, iTerm, kitty, Konsole, st, tmux, vte-based, wezterm, Windows Terminal
- 8-bit (256): rxvt, screen, xterm, Apple Terminal
- 4-bit (16): Linux Console
### Control Sequences
<details>
<summary>Click to show feature matrix</summary>
| Terminal | Query Color Scheme | Query Cursor Position | Set Window Title | Change Cursor Color | Change Default Foreground Setting | Change Default Background Setting | Bracketed Paste |
| ---------------- | :----------------: | :-------------------: | :--------------: | :-----------------: | :-------------------------------: | :-------------------------------: | :-------------: |
| alacritty | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| foot | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| kitty | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| Konsole | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ |
| rxvt | ❌ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| urxvt | ❌ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| screen | ⛔[^mux] | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ |
| st | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| tmux | ⛔[^mux] | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| vte-based[^vte] | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| wezterm | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| xterm | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ✅ |
| Linux Console | ❌ | ✅ | ⛔ | ❌ | ❌ | ❌ | ❌ |
| Apple Terminal | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ |
| iTerm | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ✅ |
| Windows cmd | ❌ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ |
| Windows Terminal | ❌ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
[^vte]: This covers all vte-based terminals, including Gnome Terminal, guake, Pantheon Terminal, Terminator, Tilix, XFCE Terminal.
[^mux]: Unavailable as multiplexers (like tmux or screen) can be connected to multiple terminals (with different color settings) at the same time.
You can help improve this list! Check out [how to](ansi_compat.md) and open an issue or pull request.
</details>
### System Commands
<details>
<summary>Click to show feature matrix</summary>
| Terminal | Copy to Clipboard (OSC52) | Hyperlinks (OSC8) | Notifications (OSC777) |
| ---------------- | :-----------------------: | :---------------: | :--------------------: |
| alacritty | ✅ | ❌[^alacritty] | ❌ |
| foot | ✅ | ✅ | ✅ |
| kitty | ✅ | ✅ | ✅ |
| Konsole | ❌[^konsole] | ✅ | ❌ |
| rxvt | ❌ | ❌ | ❌ |
| urxvt | ✅[^urxvt] | ❌ | ✅ |
| screen | ✅ | ❌[^screen] | ❌ |
| st | ✅ | ❌ | ❌ |
| tmux | ✅ | ❌[^tmux] | ❌ |
| vte-based[^vte] | ❌[^vte] | ✅ | ❌ |
| wezterm | ✅ | ✅ | ❌ |
| xterm | ✅ | ❌ | ❌ |
| Linux Console | ⛔ | ⛔ | ❌ |
| Apple Terminal | ✅[^apple] | ❌ | ❌ |
| iTerm | ✅ | ✅ | ❌ |
| Windows cmd | ❌ | ❌ | ❌ |
| Windows Terminal | ✅ | ✅ | ❌ |
[^vte]: This covers all vte-based terminals, including Gnome Terminal, guake, Pantheon Terminal, Terminator, Tilix, XFCE Terminal. OSC52 is not supported, see [issue#2495](https://gitlab.gnome.org/GNOME/vte/-/issues/2495).
[^urxvt]: Workaround for urxvt not supporting OSC52. See [this](https://unix.stackexchange.com/a/629485) for more information.
[^konsole]: OSC52 is not supported, for more info see [bug#372116](https://bugs.kde.org/show_bug.cgi?id=372116).
[^apple]: OSC52 works with a [workaround](https://github.com/roy2220/osc52pty).
[^tmux]: OSC8 is not supported, for more info see [issue#911](https://github.com/tmux/tmux/issues/911).
[^screen]: OSC8 is not supported, for more info see [bug#50952](https://savannah.gnu.org/bugs/index.php?50952).
[^alacritty]: OSC8 is not supported, for more info see [issue#922](https://github.com/alacritty/alacritty/issues/922).
</details>
## Platform Support
`termenv` works on Unix systems (like Linux, macOS, or BSD) and Windows. While
terminal applications on Unix support ANSI styling out-of-the-box, on Windows
you need to enable ANSI processing in your application first:
```go
restoreConsole, err := termenv.EnableVirtualTerminalProcessing(termenv.DefaultOutput())
if err != nil {
panic(err)
}
defer restoreConsole()
```
The above code is safe to include on non-Windows systems or when os.Stdout does
not refer to a terminal (e.g. in tests).
## Color Chart
You can find the source code used to create this chart in `termenv`'s examples.
## Related Projects
- [reflow](https://github.com/muesli/reflow) - ANSI-aware text operations
- [Lip Gloss](https://github.com/charmbracelet/lipgloss) - style definitions for nice terminal layouts 👄
- [ansi](https://github.com/muesli/ansi) - ANSI sequence helpers
## termenv in the Wild
Need some inspiration or just want to see how others are using `termenv`? Check
out these projects:
- [Bubble Tea](https://github.com/charmbracelet/bubbletea) - a powerful little TUI framework 🏗
- [Glamour](https://github.com/charmbracelet/glamour) - stylesheet-based markdown rendering for your CLI apps 💇🏻♀️
- [Glow](https://github.com/charmbracelet/glow) - a markdown renderer for the command-line 💅🏻
- [duf](https://github.com/muesli/duf) - Disk Usage/Free Utility - a better 'df' alternative
- [gitty](https://github.com/muesli/gitty) - contextual information about your git projects
- [slides](https://github.com/maaslalani/slides) - terminal-based presentation tool
## Feedback
Got some feedback or suggestions? Please open an issue or drop me a note!
- [Twitter](https://twitter.com/mueslix)
- [The Fediverse](https://mastodon.social/@fribbledom)
## License
[MIT](https://github.com/muesli/termenv/raw/master/LICENSE)