color.go

Documentation: github.com/henvic/httpretty/internal/color

     1  // Package color can be used to add color to your terminal using ANSI escape code (or sequences).
     2  //
     3  // See https://en.wikipedia.org/wiki/ANSI_escape_code
     4  // Copy modified from https://github.com/fatih/color
     5  // Copyright 2013 Fatih Arslan
     6  package color
     7  
     8  import (
     9  	"fmt"
    10  	"strconv"
    11  	"strings"
    12  )
    13  
    14  // Attribute defines a single SGR (Select Graphic Rendition) code.
    15  type Attribute int
    16  
    17  // Base attributes
    18  const (
    19  	Reset Attribute = iota
    20  	Bold
    21  	Faint
    22  	Italic
    23  	Underline
    24  	BlinkSlow
    25  	BlinkRapid
    26  	ReverseVideo
    27  	Concealed
    28  	CrossedOut
    29  )
    30  
    31  // Foreground text colors
    32  const (
    33  	FgBlack Attribute = iota + 30
    34  	FgRed
    35  	FgGreen
    36  	FgYellow
    37  	FgBlue
    38  	FgMagenta
    39  	FgCyan
    40  	FgWhite
    41  )
    42  
    43  // Foreground Hi-Intensity text colors
    44  const (
    45  	FgHiBlack Attribute = iota + 90
    46  	FgHiRed
    47  	FgHiGreen
    48  	FgHiYellow
    49  	FgHiBlue
    50  	FgHiMagenta
    51  	FgHiCyan
    52  	FgHiWhite
    53  )
    54  
    55  // Background text colors
    56  const (
    57  	BgBlack Attribute = iota + 40
    58  	BgRed
    59  	BgGreen
    60  	BgYellow
    61  	BgBlue
    62  	BgMagenta
    63  	BgCyan
    64  	BgWhite
    65  )
    66  
    67  // Background Hi-Intensity text colors
    68  const (
    69  	BgHiBlack Attribute = iota + 100
    70  	BgHiRed
    71  	BgHiGreen
    72  	BgHiYellow
    73  	BgHiBlue
    74  	BgHiMagenta
    75  	BgHiCyan
    76  	BgHiWhite
    77  )
    78  
    79  const (
    80  	escape   = "\x1b"
    81  	unescape = "\\x1b"
    82  )
    83  
    84  // Format text for terminal.
    85  // You can pass an arbitrary number of Attribute or []Attribute followed by any other values,
    86  // that can either be a string or something else (that is converted to string using fmt.Sprint).
    87  func Format(s ...interface{}) string {
    88  	if len(s) == 0 {
    89  		return ""
    90  	}
    91  
    92  	params := []Attribute{}
    93  	in := -1
    94  
    95  	for i, v := range s {
    96  		switch vt := v.(type) {
    97  		case []Attribute:
    98  			if in == -1 {
    99  				params = append(params, vt...)
   100  			} else {
   101  				s[i] = printExtraColorAttribute(v)
   102  			}
   103  		case Attribute:
   104  			if in == -1 {
   105  				params = append(params, vt)
   106  			} else {
   107  				s[i] = printExtraColorAttribute(v)
   108  			}
   109  		default:
   110  			if in == -1 {
   111  				in = i
   112  			}
   113  		}
   114  	}
   115  
   116  	if in == -1 || len(s[in:]) == 0 {
   117  		return ""
   118  	}
   119  	return wrap(params, fmt.Sprint(s[in:]...))
   120  }
   121  
   122  func printExtraColorAttribute(v interface{}) string {
   123  	return fmt.Sprintf("(EXTRA color.Attribute=%v)", v)
   124  }
   125  
   126  // StripAttributes from input arguments and return unformatted text.
   127  func StripAttributes(s ...interface{}) (raw string) {
   128  	in := -1
   129  	for i, v := range s {
   130  		switch v.(type) {
   131  		case []Attribute, Attribute:
   132  			if in != -1 {
   133  				s[i] = printExtraColorAttribute(v)
   134  			}
   135  		default:
   136  			if in == -1 {
   137  				in = i
   138  			}
   139  		}
   140  	}
   141  	if in == -1 {
   142  		in = 0
   143  	}
   144  	return fmt.Sprint(s[in:]...)
   145  }
   146  
   147  // Escape text for terminal.
   148  func Escape(s string) string {
   149  	return strings.Replace(s, escape, unescape, -1)
   150  }
   151  
   152  // sequence returns a formated SGR sequence to be plugged into a "\x1b[...m"
   153  // an example output might be: "1;36" -> bold cyan.
   154  func sequence(params []Attribute) string {
   155  	format := make([]string, len(params))
   156  	for i, v := range params {
   157  		format[i] = strconv.Itoa(int(v))
   158  	}
   159  
   160  	return strings.Join(format, ";")
   161  }
   162  
   163  // wrap the s string with the colors attributes.
   164  func wrap(params []Attribute, s string) string {
   165  	return fmt.Sprintf("%s[%sm%s%s[%dm", escape, sequence(params), s, escape, Reset)
   166  }
   167
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