package color
import (
"fmt"
"os"
"strconv"
"strings"
"github.com/mattn/go-colorable"
"github.com/mattn/go-isatty"
)
// NoColor defines if the output is colorized or not. It's dynamically set to
// false or true based on the stdout's file descriptor referring to a terminal
// or not. This is a global option and affects all colors. For more control
// over each color block use the methods DisableColor() individually.
var NoColor = !isatty.IsTerminal(os.Stdout.Fd())
// Color defines a custom color object which is defined by SGR parameters.
type Color struct {
params []Attribute
noColor *bool
}
// Attribute defines a single SGR Code
type Attribute int
const escape = "\x1b"
// Base attributes
const (
Reset Attribute = iota
Bold
Faint
Italic
Underline
BlinkSlow
BlinkRapid
ReverseVideo
Concealed
CrossedOut
)
// Foreground text colors
const (
FgBlack Attribute = iota + 30
FgRed
FgGreen
FgYellow
FgBlue
FgMagenta
FgCyan
FgWhite
)
// Foreground Hi-Intensity text colors
const (
FgHiBlack Attribute = iota + 90
FgHiRed
FgHiGreen
FgHiYellow
FgHiBlue
FgHiMagenta
FgHiCyan
FgHiWhite
)
// Background text colors
const (
BgBlack Attribute = iota + 40
BgRed
BgGreen
BgYellow
BgBlue
BgMagenta
BgCyan
BgWhite
)
// Background Hi-Intensity text colors
const (
BgHiBlack Attribute = iota + 100
BgHiRed
BgHiGreen
BgHiYellow
BgHiBlue
BgHiMagenta
BgHiCyan
BgHiWhite
)
// New returns a newly created color object.
func New(value ...Attribute) *Color {
c := &Color{params: make([]Attribute, 0)}
c.Add(value...)
return c
}
// Set sets the given parameters immediately. It will change the color of
// output with the given SGR parameters until color.Unset() is called.
func Set(p ...Attribute) *Color {
c := New(p...)
c.Set()
return c
}
// Unset resets all escape attributes and clears the output. Usually should
// be called after Set().
func Unset() {
if NoColor {
return
}
fmt.Fprintf(Output, "%s[%dm", escape, Reset)
}
// Set sets the SGR sequence.
func (c *Color) Set() *Color {
if c.isNoColorSet() {
return c
}
fmt.Fprintf(Output, c.format())
return c
}
func (c *Color) unset() {
if c.isNoColorSet() {
return
}
Unset()
}
// Add is used to chain SGR parameters. Use as many as parameters to combine
// and create custom color objects. Example: Add(color.FgRed, color.Underline).
func (c *Color) Add(value ...Attribute) *Color {
c.params = append(c.params, value...)
return c
}
func (c *Color) prepend(value Attribute) {
c.params = append(c.params, 0)
copy(c.params[1:], c.params[0:])
c.params[0] = value
}
// Output defines the standard output of the print functions. By default
// os.Stdout is used.
var Output = colorable.NewColorableStdout()
// Print formats using the default formats for its operands and writes to
// standard output. Spaces are added between operands when neither is a
// string. It returns the number of bytes written and any write error
// encountered. This is the standard fmt.Print() method wrapped with the given
// color.
func (c *Color) Print(a ...interface{}) (n int, err error) {
c.Set()
defer c.unset()
return fmt.Fprint(Output, a...)
}
// Printf formats according to a format specifier and writes to standard output.
// It returns the number of bytes written and any write error encountered.
// This is the standard fmt.Printf() method wrapped with the given color.
func (c *Color) Printf(format string, a ...interface{}) (n int, err error) {
c.Set()
defer c.unset()
return fmt.Fprintf(Output, format, a...)
}
// Println formats using the default formats for its operands and writes to
// standard output. Spaces are always added between operands and a newline is
// appended. It returns the number of bytes written and any write error
// encountered. This is the standard fmt.Print() method wrapped with the given
// color.
func (c *Color) Println(a ...interface{}) (n int, err error) {
c.Set()
defer c.unset()
return fmt.Fprintln(Output, a...)
}
// PrintFunc returns a new function that prints the passed arguments as
// colorized with color.Print().
func (c *Color) PrintFunc() func(a ...interface{}) {
return func(a ...interface{}) { c.Print(a...) }
}
// PrintfFunc returns a new function that prints the passed arguments as
// colorized with color.Printf().
func (c *Color) PrintfFunc() func(format string, a ...interface{}) {
return func(format string, a ...interface{}) { c.Printf(format, a...) }
}
// PrintlnFunc returns a new function that prints the passed arguments as
// colorized with color.Println().
func (c *Color) PrintlnFunc() func(a ...interface{}) {
return func(a ...interface{}) { c.Println(a...) }
}
// SprintFunc returns a new function that returns colorized strings for the
// given arguments with fmt.Sprint(). Useful to put into or mix into other
// string. Windows users should use this in conjuction with color.Output, example:
//
// put := New(FgYellow).SprintFunc()
// fmt.Fprintf(color.Output, "This is a %s", put("warning"))
func (c *Color) SprintFunc() func(a ...interface{}) string {
return func(a ...interface{}) string {
return c.wrap(fmt.Sprint(a...))
}
}
// SprintfFunc returns a new function that returns colorized strings for the
// given arguments with fmt.Sprintf(). Useful to put into or mix into other
// string. Windows users should use this in conjuction with color.Output.
func (c *Color) SprintfFunc() func(format string, a ...interface{}) string {
return func(format string, a ...interface{}) string {
return c.wrap(fmt.Sprintf(format, a...))
}
}
// SprintlnFunc returns a new function that returns colorized strings for the
// given arguments with fmt.Sprintln(). Useful to put into or mix into other
// string. Windows users should use this in conjuction with color.Output.
func (c *Color) SprintlnFunc() func(a ...interface{}) string {
return func(a ...interface{}) string {
return c.wrap(fmt.Sprintln(a...))
}
}
// sequence returns a formated SGR sequence to be plugged into a "\x1b[...m"
// an example output might be: "1;36" -> bold cyan
func (c *Color) sequence() string {
format := make([]string, len(c.params))
for i, v := range c.params {
format[i] = strconv.Itoa(int(v))
}
return strings.Join(format, ";")
}
// wrap wraps the s string with the colors attributes. The string is ready to
// be printed.
func (c *Color) wrap(s string) string {
if c.isNoColorSet() {
return s
}
return c.format() + s + c.unformat()
}
func (c *Color) format() string {
return fmt.Sprintf("%s[%sm", escape, c.sequence())
}
func (c *Color) unformat() string {
return fmt.Sprintf("%s[%dm", escape, Reset)
}
// DisableColor disables the color output. Useful to not change any existing
// code and still being able to output. Can be used for flags like
// "--no-color". To enable back use EnableColor() method.
func (c *Color) DisableColor() {
c.noColor = boolPtr(true)
}
// EnableColor enables the color output. Use it in conjuction with
// DisableColor(). Otherwise this method has no side effects.
func (c *Color) EnableColor() {
c.noColor = boolPtr(false)
}
func (c *Color) isNoColorSet() bool {
// check first if we have user setted action
if c.noColor != nil {
return *c.noColor
}
// if not return the global option, which is disabled by default
return NoColor
}
// Equals returns a boolean value indicating whether two colors are equal.
func (c *Color) Equals(c2 *Color) bool {
if len(c.params) != len(c2.params) {
return false
}
for _, attr := range c.params {
if !c2.attrExists(attr) {
return false
}
}
return true
}
func (c *Color) attrExists(a Attribute) bool {
for _, attr := range c.params {
if attr == a {
return true
}
}
return false
}
func boolPtr(v bool) *bool {
return &v
}
// Black is an convenient helper function to print with black foreground. A
// newline is appended to format by default.
func Black(format string, a ...interface{}) { printColor(format, FgBlack, a...) }
// Red is an convenient helper function to print with red foreground. A
// newline is appended to format by default.
func Red(format string, a ...interface{}) { printColor(format, FgRed, a...) }
// Green is an convenient helper function to print with green foreground. A
// newline is appended to format by default.
func Green(format string, a ...interface{}) { printColor(format, FgGreen, a...) }
// Yellow is an convenient helper function to print with yellow foreground.
// A newline is appended to format by default.
func Yellow(format string, a ...interface{}) { printColor(format, FgYellow, a...) }
// Blue is an convenient helper function to print with blue foreground. A
// newline is appended to format by default.
func Blue(format string, a ...interface{}) { printColor(format, FgBlue, a...) }
// Magenta is an convenient helper function to print with magenta foreground.
// A newline is appended to format by default.
func Magenta(format string, a ...interface{}) { printColor(format, FgMagenta, a...) }
// Cyan is an convenient helper function to print with cyan foreground. A
// newline is appended to format by default.
func Cyan(format string, a ...interface{}) { printColor(format, FgCyan, a...) }
// White is an convenient helper function to print with white foreground. A
// newline is appended to format by default.
func White(format string, a ...interface{}) { printColor(format, FgWhite, a...) }
func printColor(format string, p Attribute, a ...interface{}) {
if !strings.HasSuffix(format, "\n") {
format += "\n"
}
c := &Color{params: []Attribute{p}}
c.Printf(format, a...)
}
// BlackString is an convenient helper function to return a string with black
// foreground.
func BlackString(format string, a ...interface{}) string {
return New(FgBlack).SprintfFunc()(format, a...)
}
// RedString is an convenient helper function to return a string with red
// foreground.
func RedString(format string, a ...interface{}) string {
return New(FgRed).SprintfFunc()(format, a...)
}
// GreenString is an convenient helper function to return a string with green
// foreground.
func GreenString(format string, a ...interface{}) string {
return New(FgGreen).SprintfFunc()(format, a...)
}
// YellowString is an convenient helper function to return a string with yellow
// foreground.
func YellowString(format string, a ...interface{}) string {
return New(FgYellow).SprintfFunc()(format, a...)
}
// BlueString is an convenient helper function to return a string with blue
// foreground.
func BlueString(format string, a ...interface{}) string {
return New(FgBlue).SprintfFunc()(format, a...)
}
// MagentaString is an convenient helper function to return a string with magenta
// foreground.
func MagentaString(format string, a ...interface{}) string {
return New(FgMagenta).SprintfFunc()(format, a...)
}
// CyanString is an convenient helper function to return a string with cyan
// foreground.
func CyanString(format string, a ...interface{}) string {
return New(FgCyan).SprintfFunc()(format, a...)
}
// WhiteString is an convenient helper function to return a string with white
// foreground.
func WhiteString(format string, a ...interface{}) string {
return New(FgWhite).SprintfFunc()(format, a...)
}
