Color

Color is a fork of the popular fatih/color package, with added support for 256 + RGB + Hex formats.

go get github.com/bcicen/color

Examples

Standard colors

// Print with default helper functions
color.Cyan("Prints text in cyan.")

// A newline will be appended automatically
color.Blue("Prints %s in blue.", "text")

// These are using the default foreground colors
color.Red("We have red")
color.Magenta("And many others ..")

Extended colors

mint := color.Must(color.NewHex("#b5e9c6"))
pink := color.NewRGB(232, 181, 215)

fmt.Println(mint.Sprintf("such"), pink.Sprintf("color"))

// add background color
mint = mint.Merge(color.Must(color.NewBgHex("#607c78")))
pink = pink.Merge(color.Must(color.NewBgHex("607c78"))) // # prefix optional
fmt.Println(mint.Sprintf("such"), pink.Sprintf("color"))

Produces:

Mix and reuse colors

// Create a new color object
c := color.New(color.FgCyan).Add(color.Underline)
c.Println("Prints cyan text with an underline.")

// Or just add them to New()
d := color.New(color.FgCyan, color.Bold)
d.Printf("This prints bold cyan %s\n", "too!.")

// Mix up foreground and background colors, create new mixes!
red := color.New(color.FgRed)

boldRed := red.Add(color.Bold)
boldRed.Println("This will print text in bold red.")

whiteBackground := red.Add(color.BgWhite)
whiteBackground.Println("Red text with white background.")

Use your own output (io.Writer)

// Use your own io.Writer output
color.New(color.FgBlue).Fprintln(myWriter, "blue color!")

blue := color.New(color.FgBlue)
blue.Fprint(writer, "This will print text in blue.")

Custom print functions (PrintFunc)

// Create a custom print function for convenience
red := color.New(color.FgRed).PrintfFunc()
red("Warning")
red("Error: %s", err)

// Mix up multiple attributes
notice := color.New(color.Bold, color.FgGreen).PrintlnFunc()
notice("Don't forget this...")

Custom fprint functions (FprintFunc)

blue := color.New(FgBlue).FprintfFunc()
blue(myWriter, "important notice: %s", stars)

// Mix up with multiple attributes
success := color.New(color.Bold, color.FgGreen).FprintlnFunc()
success(myWriter, "Don't forget this...")

Insert into noncolor strings (SprintFunc)

// Create SprintXxx functions to mix strings with other non-colorized strings:
yellow := color.New(color.FgYellow).SprintFunc()
red := color.New(color.FgRed).SprintFunc()
fmt.Printf("This is a %s and this is %s.\n", yellow("warning"), red("error"))

info := color.New(color.FgWhite, color.BgGreen).SprintFunc()
fmt.Printf("This %s rocks!\n", info("package"))

// Use helper functions
fmt.Println("This", color.RedString("warning"), "should be not neglected.")
fmt.Printf("%v %v\n", color.GreenString("Info:"), "an important message.")

// Windows supported too! Just don't forget to change the output to color.Output
fmt.Fprintf(color.Output, "Windows support: %s", color.GreenString("PASS"))

Plug into existing code

// Use handy standard colors
color.Set(color.FgYellow)

fmt.Println("Existing text will now be in yellow")
fmt.Printf("This one %s\n", "too")

color.Unset() // Don't forget to unset

// You can mix up parameters
color.Set(color.FgMagenta, color.Bold)
defer color.Unset() // Use it in your function

fmt.Println("All text will now be bold magenta.")

Disable/Enable color

There might be a case where you want to explicitly disable/enable color output. the go-isatty package will automatically disable color output for non-tty output streams (for example if the output were piped directly to less)

Color has support to disable/enable colors both globally and for single color definitions. For example suppose you have a CLI app and a --no-color bool flag. You can easily disable the color output with:

var flagNoColor = flag.Bool("no-color", false, "Disable color output")

if *flagNoColor {
	color.NoColor = true // disables colorized output
}

It also has support for single color definitions (local). You can disable/enable color output on the fly:

c := color.New(color.FgCyan)
c.Println("Prints cyan text")

c.DisableColor()
c.Println("This is printed without any color")

c.EnableColor()
c.Println("This prints again cyan...")

Todo

Save/Return previous values
Evaluate fmt.Formatter interface

Credits

Fatih Arslan
Windows support via @mattn: colorable

License

The MIT License (MIT) - see LICENSE.md for more details

bcicen / color