Class: Babushka::ANSI

Inherits:
Object show all
Defined in:
lib/babushka/ansi.rb

Constant Summary collapse

BG_OFFSET = 
10
COLOR_REGEX = 
/black|gr[ae]y|red|green|yellow|blue|pink|cyan|white/
FG_REGEX = 
/\b#{COLOR_REGEX}\b/
BG_REGEX = 
/\bon_#{COLOR_REGEX}\b/
CTRL_REGEX = 
/\bbold|underlined?|blink(ing)?|reversed?\b/
COLOR_OFFSETS = 
{
  # This is actually "bright black", i.e. black (30) plus brightness (60),
  # which almost all terminals render as grey.
  'gray' => 90, 'grey' => 90,
  'black' => 30,
  'red' => 31,
  'green' => 32,
  'yellow' => 33,
  'blue' => 34,
  'pink' => 35,
  'cyan' => 36,
  'white' => 37
}
CTRL_OFFSETS = 
{
  'bold' => 1,
  'underline' => 4, 'underlined' => 4,
  'blink' => 5, 'blinking' => 5,
  'reverse' => 7, 'reversed' => 7
}

Class Method Summary collapse

Class Method Details

.bg_for(desc) ⇒ Object 


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# File 'lib/babushka/ansi.rb', line 58

def self.bg_for desc
  offset = fg_for((desc[BG_REGEX] || '').sub(/^on_/, ''))
  offset + BG_OFFSET unless offset.nil?
end

.ctrl_for(desc) ⇒ Object 


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# File 'lib/babushka/ansi.rb', line 63

def self.ctrl_for desc
  CTRL_OFFSETS[desc[CTRL_REGEX]]
end

.escape_for(description) ⇒ Object 


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# File 'lib/babushka/ansi.rb', line 43

def self.escape_for description
  # Make "on_grey" etc single words, so the foreground regex doesn't match.
  desc = description.strip.gsub(/\bon /, 'on_')
  # If we're on a linux pty, substitute 'bold black' for 'bright black'.
  desc = desc.gsub(/\bgrey\b/, 'bold black') if linux_pty?

  codes = [fg_for(desc), bg_for(desc), ctrl_for(desc)]

  "\e[#{codes.compact.join(';')}m"
end

.fg_for(desc) ⇒ Object 


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# File 'lib/babushka/ansi.rb', line 54

def self.fg_for desc
  COLOR_OFFSETS[desc[FG_REGEX]]
end

.linux_pty? ⇒ Boolean

Returns:

  • (Boolean) 

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# File 'lib/babushka/ansi.rb', line 67

def self.linux_pty?
  STDOUT.tty? && (ENV['TERM'] == 'linux')
end

.using_colour? ⇒ Boolean

Returns:

  • (Boolean) 

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# File 'lib/babushka/ansi.rb', line 71

def self.using_colour?
  # This means "colour", not "no colour". The "no_" is the flippable bit.
  Babushka::Base.cmdline.opts[:"[no_]color"]
end

.wrap(text, description) ⇒ Object

Wraps text with ANSI escape codes to render it as described in description. Some examples:

Babushka::ANSI.wrap('babushka', 'green')            #=> "\e[32mbabushka\e[m"
Babushka::ANSI.wrap('babushka', 'on grey')          #=> "\e[100mbabushka\e[m"
Babushka::ANSI.wrap('babushka', 'underlined blue')  #=> "\e[34;4mbabushka\e[m"
Babushka::ANSI.wrap('babushka', 'reverse')          #=> "\e[7mbabushka\e[m"


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# File 'lib/babushka/ansi.rb', line 35

def self.wrap text, description
  if !using_colour?
    text
  else
    "#{escape_for(description)}#{text}\e[m"
  end
end