ruby/doc/reline/face.md

Face

With the Reline::Face class, you can modify the text color and text decorations in your terminal emulator. This is primarily used to customize the appearance of the method completion dialog in IRB.

Usage

ex: Change the background color of the completion dialog cyan to blue

Reline::Face.config(:completion_dialog) do |conf|
  conf.define :default, foreground: :white, background: :blue
  #                                                     ^^^^^ `:cyan` by default
  conf.define :enhanced, foreground: :white, background: :magenta
  conf.define :scrollbar, foreground: :white, background: :blue
end

If you provide the above code to an IRB session in some way, you can apply the configuration. It's generally done by writing it in .irbrc.

Regarding .irbrc, please refer to the following link: https://docs.ruby-lang.org/en/master/IRB.html

Available parameters

Reline::Face internally creates SGR (Select Graphic Rendition) code according to the block parameter of Reline::Face.config method.

Key	Value	SGR Code (numeric part following "\e[")
:foreground	:black	30
	:red	31
	:green	32
	:yellow	33
	:blue	34
	:magenta	35
	:cyan	36
	:white	37
	:bright_black	90
	:gray	90
	:bright_red	91
	:bright_green	92
	:bright_yellow	93
	:bright_blue	94
	:bright_magenta	95
	:bright_cyan	96
	:bright_white	97
:background	:black	40
	:red	41
	:green	42
	:yellow	43
	:blue	44
	:magenta	45
	:cyan	46
	:white	47
	:bright_black	100
	:gray	100
	:bright_red	101
	:bright_green	102
	:bright_yellow	103
	:bright_blue	104
	:bright_magenta	105
	:bright_cyan	106
	:bright_white	107
:style	:reset	0
	:bold	1
	:faint	2
	:italicized	3
	:underlined	4
	:slowly_blinking	5
	:blinking	5
	:rapidly_blinking	6
	:negative	7
	:concealed	8
	:crossed_out	9

• The value for :style can be both a Symbol and an Array

    # Single symbol
    conf.define :default, style: :bold
    # Array
    conf.define :default, style: [:bold, :negative]
  

• The availability of specific SGR codes depends on your terminal emulator
• You can specify a hex color code to :foreground and :background color like foreground: "#FF1020". Its availability also depends on your terminal emulator

Debugging

You can see the current Face configuration by Reline::Face.configs method

Example:

irb(main):001:0> Reline::Face.configs
=>
{:default=>
  {:default=>{:style=>:reset, :escape_sequence=>"\e[0m"},
   :enhanced=>{:style=>:reset, :escape_sequence=>"\e[0m"},
   :scrollbar=>{:style=>:reset, :escape_sequence=>"\e[0m"}},
 :completion_dialog=>
  {:default=>{:foreground=>:white, :background=>:cyan, :escape_sequence=>"\e[0m\e[37;46m"},
   :enhanced=>{:foreground=>:white, :background=>:magenta, :escape_sequence=>"\e[0m\e[37;45m"},
   :scrollbar=>{:foreground=>:white, :background=>:cyan, :escape_sequence=>"\e[0m\e[37;46m"}}}

256-Color and TrueColor

Reline will automatically detect if your terminal emulator supports truecolor with ENV['COLORTERM] in 'truecolor' | '24bit'. When this env is not set, Reline will fallback to 256-color. If your terminal emulator supports truecolor but does not set COLORTERM env, add this line to .irbrc.

Reline::Face.force_truecolor