multicolor

package
v0.5.2 Latest Latest
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 Go to latest Published: Jul 22, 2020 License: MIT Imports: 7 Imported by: 2

Documentation

Overview

Package multicolor is a complement to github.com/fatih/color.

Description

It allows working with colors and attributes by using their string names. It also provides various print functions (Sprint, Sprintf, Sprintln, Print, Printf, Println, ErrorPrint, ErrorPrintf and Println) to let users provides colors and attributes before the actual text they want to print.

Use it as io.Writer

Color objects defined by fatih cannot be used to configure a stream. With multicolor, Color objects can be configured as out stream or error stream. 

import (
    "github.com/coveooss/multilogger/color"
    "github.com/fatih/color"
)

var (
    Println      = multicolor.Println
    ErrorPrintln = multicolor.ErrorPrintln
)

func main() {
    // You can use a color object to write your output.
    multicolor.New("Yellow", "BgBlue").SetOut()
    Println("Hello world!")

    // You can also convert a Color object from fatih package and use it as a stream.
    multicolor.NewColorWriter(color.New(color.FgRed)).SetError()
    ErrorPrintln("There is something wrong!")
}

Example

Here is a complete example: 

import (
    "github.com/coveooss/multilogger/color"
    "github.com/fatih/color"
)

var Println = multicolor.Println

func main() {
    // You can use a color object to write your output.
    c := multicolor.New("Red", "BgWhite")
    c.Println("Hello world!")

    // Or you can directly supply your color to the global Print and ErrorPrint functions.
    // Multiple attributes can be combined, they will be ignored if they are not supported on your OS.
    multicolor.Println("BgBlue, Underline, CrossedOut, Faint, BlinkSlow, Italic", "The sky is blue.")
    fmt.Println("Hello, I should be in Hi Green.")

    // It is also possible to set the colors for all following outputs. The color setting
    // will then remain until another color is sent to the same output.
    multicolor.Set("HiGreen")

    // It is possible to use a mix of strings, multicolor.Attribute or color.Attribute (from fatih)
    // to configure your color object.
    // You can configure the default out stream to always print in color.
    multicolor.New(multicolor.BgGreen, color.FgWhite, "underline").SetOut()
    Println("I will be printed in color")
}

The attributes name are not case significant. Any attributes defined in the constants can be used as string. For simplicity, it is allowed to forget the prefix FG to specify foreground colors. 

Blue      = FgBlue
HiMagenta = FgHiMagenta

Index

Examples

Constants

View Source 
const (
	Reset attribute = iota
	Bold
	Faint
	Italic
	Underline
	BlinkSlow
	BlinkRapid
	ReverseVideo
	Concealed
	CrossedOut
)

The following constant are copied from the color package in order to get the actual string names.

View Source 
const (
	FgBlack attribute = iota + 30
	FgRed
	FgGreen
	FgYellow
	FgBlue
	FgMagenta
	FgCyan
	FgWhite
)

Foreground attributes

View Source 
const (
	FgHiBlack attribute = iota + 90
	FgHiRed
	FgHiGreen
	FgHiYellow
	FgHiBlue
	FgHiMagenta
	FgHiCyan
	FgHiWhite
)

Foreground attributes high intensity

View Source 
const (
	BgBlack attribute = iota + 40
	BgRed
	BgGreen
	BgYellow
	BgBlue
	BgMagenta
	BgCyan
	BgWhite
)

Background attributes

View Source 
const (
	BgHiBlack attribute = iota + 100
	BgHiRed
	BgHiGreen
	BgHiYellow
	BgHiBlue
	BgHiMagenta
	BgHiCyan
	BgHiWhite
)

Background attributes high intensity

Variables

View Source 
var (
	Black     = color.Black
	Red       = color.Red
	Green     = color.Green
	Yellow    = color.Yellow
	Blue      = color.Blue
	Magenta   = color.Magenta
	Cyan      = color.Cyan
	White     = color.White
	HiBlack   = color.HiBlack
	HiRed     = color.HiRed
	HiGreen   = color.HiGreen
	HiYellow  = color.HiYellow
	HiBlue    = color.HiBlue
	HiMagenta = color.HiMagenta
	HiCyan    = color.HiCyan
	HiWhite   = color.HiWhite

	BlackString     = color.BlackString
	RedString       = color.RedString
	GreenString     = color.GreenString
	YellowString    = color.YellowString
	BlueString      = color.BlueString
	MagentaString   = color.MagentaString
	CyanString      = color.CyanString
	WhiteString     = color.WhiteString
	HiBlackString   = color.HiBlackString
	HiRedString     = color.HiRedString
	HiGreenString   = color.HiGreenString
	HiYellowString  = color.HiYellowString
	HiBlueString    = color.HiBlueString
	HiMagentaString = color.HiMagentaString
	HiCyanString    = color.HiCyanString
	HiWhiteString   = color.HiWhiteString

	Unset = color.Unset
)

Imports fatih/color functions into the current package.

Functions

func ErrorPrint 

func ErrorPrint(args ...interface{}) (int, error)

ErrorPrint call standard fmt.Printf function but using the color out stream.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetError(os.Stdout)

// Print is used to output to a color stream.
ErrorPrint("Yellow", "Hello")

// It behaves like regular fmt.Print.
ErrorPrint("red", "This", "is", "concatenated", 1, 2, 3)

Output:

HelloThisisconcatenated1 2 3

func ErrorPrintf 

func ErrorPrintf(args ...interface{}) (int, error)

ErrorPrintf call standard fmt.Printf function but using the color out stream.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetError(os.Stdout)

// ErrorPrintf is used to output to a color stream.
ErrorPrintf("Yellow", "Hello")

// It behaves like regular fmt.Printf.
// It must have a format string if there is more that one argument after the attributes.
ErrorPrintf("red", "Hello %s %d\n", "world", 123)

// Otherwise, the result is far from beautiful ;-).
ErrorPrintf("red", "Hello", "world!", 1, math.Pi)

Output:

HelloHello world 123
Hello%!!(MISSING)(EXTRA string=world!, int=1, float64=3.141592653589793)

func ErrorPrintln 

func ErrorPrintln(args ...interface{}) (int, error)

ErrorPrintln call standard fmt.Println function but using the color out stream.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetError(os.Stdout)

// ErrorPrintln is used to output to a color stream.
ErrorPrintln("Yellow", "Hello")

// It behaves like regular fmt.Println.
ErrorPrintln("red", "This", "is", "not", "concatenated", 1, 2, 3)

Output:

Hello
This is not concatenated 1 2 3

func FormatMessage 

func FormatMessage(args ...interface{}) string

FormatMessage analyses the arguments to determine if Sprintf or Sprintln should be used.

func Print 

func Print(args ...interface{}) (int, error)

Print call standard fmt.Printf function but using the color out stream.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetOut(os.Stdout)

// Print is used to output to a color stream.
Print("Yellow", "Hello")

// It behaves like regular fmt.Print.
Print("red", "This", "is", "concatenated", 1, 2, 3)

Output:

HelloThisisconcatenated1 2 3

func Printf 

func Printf(args ...interface{}) (int, error)

Printf behave as Printf, it expects to have a format string after the color attributes.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetOut(os.Stdout)

// Printf is used to output to a color stream.
Printf("Yellow", "Hello")

// It behaves like regular fmt.Printf.
// It must have a format string if there is more that one argument after the attributes.
Printf("red", "Hello %s %d\n", "world", 123)

// Otherwise, the result is far from beautiful ;-).
Printf("red", "Hello", "world!", 1, math.Pi)

Output:

HelloHello world 123
Hello%!!(MISSING)(EXTRA string=world!, int=1, float64=3.141592653589793)

func Println 

func Println(args ...interface{}) (int, error)

Println call standard fmt.Println function but using the color out stream.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetOut(os.Stdout)

// Print is used to output to a color stream.
Println("Yellow", "Hello")

// It behaves like regular fmt.Println.
Println("red", "This", "is", "not", "concatenated", 1, 2, 3)

Output:

Hello
This is not concatenated 1 2 3

func Sprint 

func Sprint(args ...interface{}) string

Sprint returns a string formated with attributes that are supplied before.

Example 
// Sprint is also very flexible.

// You can use Sprint to format a message in color by prefixing the real text by color attributes.
fmt.Println(Sprint("Yellow", color.Underline, "Hello"))

// As with New, you can mix strings & color attribute. You can also use Sprint like a Sprintf function.
// Color attributes following the message are not considered as attributes and are simply printed.
fmt.Println(Sprint("yellow+underline", color.BlinkRapid, "color1=%v color2=%s", color.BgBlue, "red"))

// If the arguments are not compatible with Sprintf, the result shows the error.
fmt.Println(Sprint("HiRed", "Faint", "Wrong format %d %s", color.BgCyan))

// As with fmt.Sprint, strings are concatenated and first element following a string is also concatenated.
fmt.Println(Sprint("Red, CrossedOut", color.BlinkRapid, "Hello", color.BgMagenta, "red", "BOLD", 1, 2, 3))

Output:

Hello
color1=44 color2=red
Wrong format %d %s46
Hello45redBOLD1 2 3

func Sprintf 

func Sprintf(args ...interface{}) string

Sprintf returns a string formated with attributes that are supplied before.

func Sprintln 

func Sprintln(args ...interface{}) string

Sprintln returns a string formated with attributes that are supplied before.

Example 
// Sprint is also very flexible.

// You can use Sprint to format a message in color by prefixing the real text by color attributes.
fmt.Print(Sprintln("Yellow", color.Underline, "Hello"))

// As with New, you can mix strings & color attribute. You can also use Sprint like a Sprintf function.
// Color attributes following the message are not considered as attributes and are simply printed.
fmt.Print(Sprintln("yellow+underline", color.BlinkRapid, "color1=%v color2=%s", color.BgBlue, "red"))

// If the format argument appears to have a format, the function behave like a fmt.Sprintf followed by a fmt.Sprintln.
fmt.Print(Sprintln("HiRed", "Faint", "Background Hi Magenta is %d", color.BgHiMagenta))

// If the arguments are not compatible with Sprintf, the result shows the error.
fmt.Print(Sprintln("HiRed", "Faint", "Wrong format %d %s", color.BgCyan))

// As with fmt.Sprintln, all elements are separated by a space.
fmt.Print(Sprintln("Red, CrossedOut", color.BlinkRapid, "Hello", color.BgMagenta, "red", "BOLD", 1, 2, 3))

Output:

Hello
color1=44 color2=red
Background Hi Magenta is 105
Wrong format %d %s46
Hello 45 red BOLD 1 2 3

Types

type Attribute 

type Attribute = color.Attribute

Attribute is a copy of fatih/Attribute used to generate stringable attributes.

func Attributes 

func Attributes(attributes ...interface{}) []Attribute

Attributes convert any object representation to valid color attributes. It will panic if an invalid attribute is provided.

func TryConvertAttributes 

func TryConvertAttributes(attributes ...interface{}) ([]Attribute, error)

TryConvertAttributes tries to convert any object representation to valid color attribute. It returns an error if some parameters cannot be converted to valid attributes.

type Color 

type Color = color.Color

Color is imported from fatih/color.

type ColorWriter 

type ColorWriter struct {
	*color.Color
	// contains filtered or unexported fields
}

ColorWriter is used as a regular color.Color object, but it is able to be used as io.Writer.

func New 

func New(attributes ...interface{}) *ColorWriter

New returns a ColorWriter build from supplied attribute names. This function will panic if invalid attributes are supplied.

Example 
// It accepts an enumeration of attributes.
writer := New(color.FgGreen, color.Underline)
fmt.Printf("%+v", *writer.Color)

Output:

{params:[32 4] noColor:<nil>}
Example (Error) 
// But it panics if you supplied invalid attribute.
func() {
	defer func() { fmt.Println(recover()) }()
	color := New("red, invalid | rouge")
	fmt.Printf("%+v", color)
}()

Output:

Attribute not found invalid
Attribute not found rouge
Example (Mixup) 
// It can also mix strings and attributes
writer := New(color.BgRed, "crossedout")
fmt.Printf("%+v", *writer.Color)

Output:

{params:[41 9] noColor:<nil>}
Example (String_separated) 
// Or separated by any non letter. Case is also non significant.
writer := New("RED | underline, CrossedOUT+BgYellow")
fmt.Printf("%+v", *writer.Color)

Output:

{params:[31 4 9 43] noColor:<nil>}
Example (With_array) 
// It also accepts an array of attributes.
writer := New([]color.Attribute{color.FgGreen, color.Underline})
fmt.Printf("%+v", *writer.Color)

Output:

{params:[32 4] noColor:<nil>}
Example (With_strings) 
// It also accepts a list of string attributes.
writer := New("FgHiGreen", "Underline", "BgYellow")
fmt.Printf("%+v", *writer.Color)

Output:

{params:[92 4 43] noColor:<nil>}

func NewColorWriter 

func NewColorWriter(c *color.Color) *ColorWriter

NewColorWriter creates a writeable color from a fatih Color object.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetOut(os.Stdout)

c := color.New(color.FgYellow, color.BgHiWhite, color.Italic)
SetOut(NewColorWriter(c))
Println("I should be colored")

Output:

I should be colored

func Set 

func Set(attributes ...interface{}) *ColorWriter

Set changes the current output color for all following output to stdout. This function will panic if invalid attributes are supplied.

Example 
// It accepts an enumeration of attributes.
Set("Red+BgYellow", color.Underline)
fmt.Println("I should be colored")

// But it panics if you supplied invalid attribute.
func() {
	defer func() { fmt.Println(recover()) }()
	Set("red, invalid | rouge")
}()

Output:

I should be colored
Attribute not found invalid
Attribute not found rouge

func SetError 

func SetError(out io.Writer) *ColorWriter

SetError lets the user redefine the default writer used to print to stderr. This writer will then be used by functions multicolor.ErrorPrint, multicolor.ErrorPrintf and multicolor.ErrorPrintln.

The function returns the result color object if it is a colorable stream, otherwise, it returns nil.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetError(os.Stdout)

SetError(New("BgRed+Green"))
ErrorPrintln("I should be colored")

Output:

I should be colored

func SetOut 

func SetOut(out io.Writer) *ColorWriter

SetOut lets the user redefine the default writer used to print to stdout. This writer will then be used by functions multicolor.Print, multicolor.Printf and multicolor.Println.

The function returns the result color object if it is a colorable stream, otherwise, it returns nil.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetOut(os.Stdout)

SetOut(New("BgGreen+Yellow"))
Println("I should be colored")

Output:

I should be colored

func TryNew 

func TryNew(attributes ...interface{}) (*ColorWriter, error)

TryNew returns a ColorWriter build from supplied attribute names. If attributes cannot be converted into valid Attribute, an error is returned.

Example 
// You can avoid panic by using TryNew.
if _, err := TryNew("FgBLUE Another invalid color BGYellow"); err != nil {
	fmt.Println(err)
}

Output:

Attribute not found Another
Attribute not found invalid
Attribute not found color

func TrySet 

func TrySet(attributes ...interface{}) (*ColorWriter, error)

TrySet changes the current output color for all following output to stdout. If attributes cannot be converted into valid Attribute, an error is returned.

Example 
// You can avoid panic by using TrySet.
if _, err := TrySet("FgBLUE Another invalid color BGYellow"); err != nil {
	fmt.Println(err)
}

Output:

Attribute not found Another
Attribute not found invalid
Attribute not found color

func (*ColorWriter) SetError 

func (c *ColorWriter) SetError() *ColorWriter

SetError uses the current color as the default stderr for multicolor.ErrorPrint functions.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetOut(os.Stdout)
SetError(os.Stdout)

// SetOut can be called as a method on a Color object. It can even be used directly
// on the same line.
New("BgGreen+Yellow").SetError().Println("Hello!")
ErrorPrint("I should be colored")
Println(", while I shouldn't")

Output:

Hello!
I should be colored, while I shouldn't

func (*ColorWriter) SetOut 

func (c *ColorWriter) SetOut() *ColorWriter

SetOut uses the current color as the default stdout for multicolor.Print functions.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetOut(os.Stdout)

// SetOut can be called as a method on a Color object. It can even be used directly
// on the same line.
New("BgGreen+Yellow").SetOut().Println("Hello!")
Println("I should be colored")

Output:

Hello!
I should be colored

func (*ColorWriter) Write 

func (c *ColorWriter) Write(p []byte) (n int, err error)

Writer is the implementation of io.Writer. You should not call directly this function. The function will fail if called directly on a stream that have not been configured as out stream.

Example 
// We set the output because go test framework redirect os.Stdout and ignore os.Stderr
SetOut(os.Stdout)

color := New("BgGreen+Yellow")
n, err := color.Write([]byte("Not set yet\n"))
fmt.Printf("n=%d, err=%v\n", n, err)

color = color.SetOut()
n, err = color.Write([]byte("Should be ok\n"))
fmt.Printf("n=%d, err=%v\n", n, err)

Output:

n=0, err=Color is not configured as writer, call SetOut or SetError before using it
Should be ok
n=13, err=<nil>

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