Rainbow is a ruby gem for colorizing printed text on ANSI terminals.
It provides a string presenter object, which adds several methods to your strings for wrapping them in ANSI escape codes. These codes when printed in a terminal change text attributes like text color, background color, intensity etc.
To make your string colored wrap it with Rainbow() presenter and call
.color(<color name>) on it.
require 'rainbow'
puts Rainbow("this is red").red + " and " + Rainbow("this on yellow bg").bg(:yellow) + " and " + Rainbow("even bright underlined!").underline.bright
# => "\e[31mthis is red\e[0m and \e[43mthis on yellow bg\e[0m and \e[4m\e[1meven bright underlined!\e[0m"
Rainbow presenter adds the following methods to presented string:
color(c)(withforeground, andfgaliases)background(c)(withbgalias)brightunderlineblinkinversehidefaint(not well supported by terminal emulators)italic(not well supported by terminal emulators)cross_out,strike
Text color can also be changed by calling a method named by a color:
blackredgreenyellowbluemagentacyanwhiteaquasilveraliceblueindianred
All of the methods return self (the presenter object) so you can chain method
calls:
Rainbow("hola!").blue.bright.underlineIf you want to use the Refinements version, you can:
require 'rainbow/refinement'
using Rainbow
puts "Hi!".greenHere's an IRB session example:
>> 'Hello, World!'.blue.bright.underline
NoMethodError: undefined method `blue' for "Hello, World!":String
(ripl):1:in `<main>'
>> using Rainbow
=> main
>> 'Hello, World!'.blue.bright.underline
=> "\e[34m\e[1m\e[4mHello, World!\e[0m"
Both color and background accept color specified in any
of the following ways:
-
ANSI color number (where 0 is black, 1 is red, 2 is green and so on):
Rainbow("hello").color(1) -
ANSI color name or X11 color name as a symbol:
Rainbow("hello").color(:yellow). This can be simplified toRainbow("hello").yellowSee Color list for all available color names.
Note that ANSI colors can be changed in accordance with terminal setting.
But X11 color is just a syntax sugar for RGB triplet. So you always see what you specified. -
RGB triplet as separate values in the range 0-255:
Rainbow("hello").color(115, 23, 98) -
RGB triplet as a hex string:
Rainbow("hello").color("FFC482")orRainbow("hello").color("#FFC482")
When you specify a color with a RGB triplet rainbow finds the nearest match from 256 colors palette. Note that it requires a 256-colors capable terminal to display correctly.
You can pick a random color with Rainbow, it's a one-liner:
colors = Range.new(0,7).to_a
"whoop dee doop".chars.map { |char| Rainbow(char).color(colors.sample) }.join
# => "\e[36mw\e[0m\e[37mh\e[0m\e[34mo\e[0m\e[34mo\e[0m\e[37mp\e[0m\e[34m \e[0m\e[36md\e[0m\e[33me\e[0m\e[34me\e[0m\e[37m \e[0m\e[32md\e[0m\e[35mo\e[0m\e[33mo\e[0m\e[36mp\e[0m"
colors = [:aliceblue, :antiquewhite, :aqua, :aquamarine, :azure, :beige, :bisque, :blanchedalmond, :blueviolet]
"whoop dee doop".chars.map { |char| Rainbow(char).color(colors.sample) }.join
# => "\e[38;5;135mw\e[0m\e[38;5;230mh\e[0m\e[38;5;231mo\e[0m\e[38;5;135mo\e[0m\e[38;5;231mp\e[0m\e[38;5;231m \e[0m\e[38;5;122md\e[0m\e[38;5;231me\e[0m\e[38;5;231me\e[0m\e[38;5;230m \e[0m\e[38;5;122md\e[0m\e[38;5;51mo\e[0m\e[38;5;51mo\e[0m\e[38;5;51mp\e[0m"Rainbow can be enabled/disabled globally by setting:
Rainbow.enabled = true/falseWhen disabled all the methods return an unmodified string
(Rainbow("hello").red == "hello").
It's enabled by default, unless STDOUT/STDERR is not a TTY or a terminal is dumb.
Rainbow() and Rainbow.enabled operate on the global Rainbow wrapper
instance. If you would like to selectively enable/disable coloring in separate
parts of your application you can get a new Rainbow wrapper instance for each
of them and control the state of coloring during the runtime.
rainbow_one = Rainbow.new
rainbow_two = Rainbow.new
rainbow_one.enabled = false
Rainbow("hello").red # => "\e[31mhello\e[0m" ("hello" if not on TTY)
rainbow_one.wrap("hello").red # => "hello"
rainbow_two.wrap("hello").red # => "\e[31mhello\e[0m" ("hello" if not on TTY)By default each new instance inherits enabled/disabled state from the global
Rainbow.enabled.
This feature comes handy for example when you have multiple output formatters in your application and some of them print to a terminal but others write to a file. Normally rainbow would detect that STDIN/STDERR is a TTY and would colorize all the strings, even the ones that go through file writing formatters. You can easily solve that by disabling coloring for the Rainbow instances that are used by formatters with file output.
Add it to your Gemfile:
gem 'rainbow'Or just install it via rubygems:
gem install rainbowblack, red, green, yellow, blue, magenta, cyan, white
aliceblue, antiquewhite, aqua, aquamarine, azure, beige, bisque,
blanchedalmond, blueviolet, brown, burlywood, cadetblue, chartreuse,
chocolate, coral, cornflower, cornsilk, crimson, darkblue,
darkcyan, darkgoldenrod, darkgray, darkgreen, darkkhaki,
darkmagenta, darkolivegreen, darkorange, darkorchid, darkred,
darksalmon, darkseagreen, darkslateblue, darkslategray, darkturquoise,
darkviolet, deeppink, deepskyblue, dimgray, dodgerblue, firebrick,
floralwhite, forestgreen, fuchsia, gainsboro, ghostwhite, gold,
goldenrod, gray, greenyellow, honeydew, hotpink, indianred,
indigo, ivory, khaki, lavender, lavenderblush, lawngreen,
lemonchiffon, lightblue, lightcoral, lightcyan, lightgoldenrod,
lightgray, lightgreen, lightpink, lightsalmon, lightseagreen,
lightskyblue, lightslategray, lightsteelblue, lightyellow, lime,
limegreen, linen, maroon, mediumaquamarine, mediumblue,
mediumorchid, mediumpurple, mediumseagreen, mediumslateblue,
mediumspringgreen, mediumturquoise, mediumvioletred, midnightblue,
mintcream, mistyrose, moccasin, navajowhite, navyblue, oldlace,
olive, olivedrab, orange, orangered, orchid, palegoldenrod,
palegreen, paleturquoise, palevioletred, papayawhip, peachpuff,
peru, pink, plum, powderblue, purple, rebeccapurple, rosybrown,
royalblue, saddlebrown, salmon, sandybrown, seagreen, seashell,
sienna, silver, skyblue, slateblue, slategray, snow, springgreen,
steelblue, tan, teal, thistle, tomato, turquoise, violet,
webgray, webgreen, webmaroon, webpurple, wheat, whitesmoke,
yellowgreen
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