Module: Terminal::Ansi

Defined in:
lib/terminal/ansi.rb,
lib/terminal/ansi/named_colors.rb,
lib/terminal/ansi/screen_viewer.rb

Overview

ANSI escape code generation and BBCode-to-ANSI conversion.

Provides methods for text decoration, color, cursor control, screen manipulation, hyperlinks, notifications, and progress indicators. All methods return ANSI escape sequence strings — they do not write to the terminal directly.

Colors can be specified as named symbols, 256-color indices, hex strings, or CSS/X11 color names.

Examples:

Generate ANSI codes

Terminal::Ansi[:bold, :red]   # => "\e[1;31m"
Terminal::Ansi[:on_blue]      # => "\e[44m"

BBCode to ANSI

Terminal::Ansi.bbcode('[bold]Hello[/bold]') # => "\e[1mHello\e[m"

Defined Under Namespace

Classes: ScreenViewer

Class Attribute Summary collapse

ANSI Control Code Generation collapse

BBcode Generation collapse

Tool Functions collapse

Class Attribute Details

.attributes ⇒ Array<Symbol> (readonly)

All known text attribute names (bold, italic, underline, etc.).

Returns:

  • (Array<Symbol>) 


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# File 'lib/terminal/ansi.rb', line 27

def attributes = @attributes.dup

.colors ⇒ Array<Symbol> (readonly)

All known basic color names.

Returns:

  • (Array<Symbol>) 


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# File 'lib/terminal/ansi.rb', line 33

def colors = @colors.dup

.named_colors ⇒ Array<Symbol> (readonly)

All CSS/X11 named colors.

Returns:

  • (Array<Symbol>) 


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# File 'lib/terminal/ansi.rb', line 39

def named_colors = NAMED_COLORS.keys.map!(&:to_sym)

Class Method Details

.[](*attributes) ⇒ String

Generate an ANSI escape sequence from attribute names or color indices.

Accepts symbols (:bold, :red), strings ("bold", "#ff0000"), or integers for 256-color palette (0-255 foreground, 256-511 background, 512-767 underline color).

Examples:

Named attributes

Terminal::Ansi[:bold, :italic, :green] # => "\e[1;3;32m"

256-color palette

Terminal::Ansi[196]       # foreground color 196
Terminal::Ansi[256 + 21]  # background color 21

Hex colors

Terminal::Ansi[:ff8800] # => "\e[38;2;255;136;0m"

Named CSS colors

Terminal::Ansi[:coral] # => "\e[38;2;255;127;80m"

Parameters:

  • attributes (Array<String, Symbol, Integer>) —

    ANSI attributes

Returns:

  • (String) —

    ANSI escape sequence

Raises:

  • (ArgumentError) —

    for unknown attributes



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# File 'lib/terminal/ansi.rb', line 65

def [](*attributes)
  return +'' if attributes.empty?
  "\e[#{
    attributes
      .map! do |arg|
        case arg
        when String
          @attr_str_map[arg] || _invalid(arg)
        when Symbol
          @attr_sym_map[arg] || _invalid(arg)
        when (0..255)
          "38;5;#{arg}"
        when (256..511)
          "48;5;#{arg - 256}"
        when (512..767)
          "58;5;#{arg - 512}"
        else
          _invalid(arg)
        end
      end
      .join(';')
  }m"
end

.ansi?(str) ⇒ true, false

Test whether a string contains ANSI escape codes.

Examples:

Terminal::Ansi.ansi?("\e[1mHi\e[m") # => true
Terminal::Ansi.ansi?("Hello")       # => false

Parameters:

  • str (#to_s) —

    the string to test

Returns:

  • (true, false) 


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# File 'lib/terminal/ansi.rb', line 264

def ansi?(str) = @re_test.match?(str.to_s)

.bbcode(str) ⇒ String

Convert BBCode markup to ANSI escape codes.

Tags like [bold] are converted to their ANSI equivalents; [/bold] or [/] resets. Unknown tags are left unchanged. Escape a tag with a backslash: [\\bold] renders as [bold].

Examples:

Terminal::Ansi.bbcode('[bold red]Hello[/] World')
# => "\e[1;31mHello\e[m World"

Escaped tag

Terminal::Ansi.bbcode('[\\bold]') # => "[bold]"

Parameters:

  • str (#to_s) —

    text with BBCode markup

Returns:

  • (String) —

    text with ANSI escape codes

See Also:



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# File 'lib/terminal/ansi.rb', line 191

def bbcode(str)
  str = str.to_s
  return str.dup unless str.index('[')
  str.gsub(@re_bbcode) do |match_str|
    match = Regexp.last_match(1) or next match_str
    next try_convert(match) || match_str if match[0] != '\\'
    match[0] = ''
    "[#{match}]"
  end
end

.char_repeat(count = 1) ⇒ String

Repeat the last printed character.

Parameters:

  • count (Integer) (defaults to: 1) —

    number of repetitions

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 452

def char_repeat(count = 1) = "\e[#{count}b"

.cursor_back(columns = 1) ⇒ String

Move cursor left.

Parameters:

  • columns (Integer) (defaults to: 1) —

    number of columns

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 331

def cursor_back(columns = 1) = "\e[#{columns}D"

.cursor_column(column = 1) ⇒ String

Move cursor to absolute column.

Parameters:

  • column (Integer) (defaults to: 1) —

    column number

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 349

def cursor_column(column = 1) = "\e[#{column}G"

.cursor_column_rel(column = 1) ⇒ String

Move cursor right by relative columns.

Parameters:

  • column (Integer) (defaults to: 1) —

    number of columns

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 355

def cursor_column_rel(column = 1) = "\e[#{column}a"

.cursor_down(lines = 1) ⇒ String

Move cursor down.

Parameters:

  • lines (Integer) (defaults to: 1) —

    number of lines

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 319

def cursor_down(lines = 1) = "\e[#{lines}B"

.cursor_forward(columns = 1) ⇒ String

Move cursor right.

Parameters:

  • columns (Integer) (defaults to: 1) —

    number of columns

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 325

def cursor_forward(columns = 1) = "\e[#{columns}C"

.cursor_hide ⇒ String

Hide cursor.

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 385

def cursor_hide = +CURSOR_HIDE

.cursor_next_line(lines = 1) ⇒ String

Move cursor to beginning of line, N lines down.

Parameters:

  • lines (Integer) (defaults to: 1) —

    number of lines

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 337

def cursor_next_line(lines = 1) = "\e[#{lines}E"

.cursor_pos(row, column = nil) ⇒ String

Move cursor to absolute position.

Examples:

Terminal::Ansi.cursor_pos(1, 1)  # home position
Terminal::Ansi.cursor_pos(10, 5) # row 10, column 5

Parameters:

  • row (Integer, nil) —

    row number; nil moves to home

  • column (Integer, nil) (defaults to: nil) —

    column number

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 372

def cursor_pos(row, column = nil)
  return column ? "\e[;#{column}H" : "\e[H" unless row
  column ? "\e[#{row};#{column}H" : "\e[#{row}H"
end

.cursor_prev_line(lines = 1) ⇒ String

Move cursor to beginning of line, N lines up.

Parameters:

  • lines (Integer) (defaults to: 1) —

    number of lines

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 343

def cursor_prev_line(lines = 1) = "\e[#{lines}F"

.cursor_restore_pos ⇒ String

Restore previously saved cursor position.

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 399

def cursor_restore_pos = +CURSOR_POS_RESTORE

.cursor_row_rel(row = 1) ⇒ String

Move cursor down by relative rows.

Parameters:

  • row (Integer) (defaults to: 1) —

    number of rows

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 361

def cursor_row_rel(row = 1) = "\e[#{row}e"

.cursor_save_pos ⇒ String

Save current cursor position.

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 392

def cursor_save_pos = +CURSOR_POS_SAVE

.cursor_show ⇒ String

Show cursor.

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 380

def cursor_show = +CURSOR_SHOW

.cursor_up(lines = 1) ⇒ String

Move cursor up.

Parameters:

  • lines (Integer) (defaults to: 1) —

    number of lines

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 313

def cursor_up(lines = 1) = "\e[#{lines}A"

.decorate(str, *attributes, reset: true) ⇒ String

Wrap a string with ANSI escape codes.

Examples:

Terminal::Ansi.decorate('Hello', :bold, :red)
# => "\e[1;31mHello\e[m"

Without reset

Terminal::Ansi.decorate('Hello', :bold, reset: false)
# => "\e[1mHello"

Parameters:

  • str (#to_s) —

    the string to decorate

  • attributes (Array<String, Symbol, Integer>) —

    ANSI attributes to apply

  • reset (true, false) (defaults to: true) —

    append a reset code at the end

Returns:

  • (String) —

    the decorated string



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# File 'lib/terminal/ansi.rb', line 103

def decorate(str, *attributes, reset: true)
  attributes = self[*attributes]
  attributes.empty? ? "#{str}" : "#{attributes}#{str}#{"\e[m" if reset}"
end

.escape_bbcode(str) ⇒ String

Escape BBCode tags so they render as literal text after bbcode processing.

Examples:

Terminal::Ansi.escape_bbcode('[bold]Hi[/bold]')
# => "[\\bold]Hi[\\/bold]"

Parameters:

  • str (#to_s) —

    text with BBCode markup

Returns:

  • (String) —

    text with BBCode tags escaped

See Also:



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# File 'lib/terminal/ansi.rb', line 237

def escape_bbcode(str)
  str = str.to_s
  return str.dup unless str.index('[')
  str.gsub(@re_bbcode) do |match_str|
    fc = match_str[1]
    next match_str if fc == '\\' || fc == ']'
    match = Regexp.last_match(1) or next match_str
    next match_str if (parts = match.split).empty?
    next "[\\#{match}]" if parts.all? { @attr_str_map[it] }
    match_str
  end
end

.line_erase(part = :all) ⇒ String

Erase part of the current line.

Parameters:

  • part (Symbol) (defaults to: :all) —

    area to erase: :all, :to_end, or :to_start

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 459

def line_erase(part = :all) = "\e[#{@line_erase[part]}K"

.link(url, text, **params) ⇒ String

Create a complete hyperlink (OSC 8).

Examples:

Terminal::Ansi.link('https://example.com', 'Example')

Parameters:

  • text (String) —

    the visible link text

  • url (#to_s) —

    the link URL

  • params (Hash) —

    optional link parameters (e.g., id:)

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 504

def link(url, text, **params)
  "#{link_start(url, **params)}#{text}#{LINK_END}"
end

.link_end ⇒ String

End a hyperlink.

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 491

def link_end = +LINK_END

.link_start(url, **params) ⇒ String

Note:

Supported by Ghostty, iTerm2, Kitty, Rio, Tabby, WezTerm.

Start a hyperlink (OSC 8).

Parameters:

  • url (#to_s) —

    the link URL

  • params (Hash) —

    optional link parameters (e.g., id:)

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 482

def link_start(url, **params)
  "\e]8;#{params.map { it.join('=') }.join(':')};#{url}\a"
end

.notify(text) ⇒ String

Note:

Supported by Ghostty, iTerm2, Kitty, WezTerm.

Send a desktop notification via the terminal.

Examples:

Terminal.raw_write(Terminal::Ansi.notify('Build complete!'))

Parameters:

  • text (to_s) —

    the notification text

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 516

def notify(text) = "\e]9;#{text}\a"

.plain(str) ⇒ String

Remove both BBCode tags and ANSI escape codes, returning plain text.

Examples:

Terminal::Ansi.plain('[bold]Hello[/bold]')     # => "Hello"
Terminal::Ansi.plain("\e[1mHello\e[m")         # => "Hello"

Parameters:

  • str (#to_s) —

    text with BBCode and/or ANSI codes

Returns:

  • (String) —

    plain text



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# File 'lib/terminal/ansi.rb', line 297

def plain(str)
  str = unbbcode(str)
  str.gsub!(@re_test, '') if str.index("\e")
  str
end

.progress(state, percent = 0) ⇒ String

Note:

Supported by Ghostty, iTerm2, Kitty.

Show or update a progress indicator in the terminal tab/title bar.

Examples:

Terminal.raw_write(Terminal::Ansi.progress(50))     # 50%
Terminal.raw_write(Terminal::Ansi.progress(:error)) # error state
Terminal.raw_write(Terminal::Ansi.progress(nil))    # hide

Parameters:

  • state (Symbol, Numeric, true, false) —

    progress state:

    • :show or true to show, :err/:error, :warn/:warning, :indeterminate, a Numeric (0-100) to set percentage, or any other value to hide
  • percent (#to_i) (defaults to: 0) —

    progress percentage (0-100, used with :show state)

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 535

def progress(state, percent = 0)
  case state
  when :show, true
    state = 1
  when :err, :error
    state = 2
  when :warn, :warning
    state = 4
  when Numeric
    percent, state = state, 1
  when :indeterminate
    return +PROGRESS_SHOW_INDETERMINATE
  else
    return +PROGRESS_HIDE
  end
  "\e]9;4;#{state};#{percent.to_i.clamp(0, 100)}\a"
end

.rainbow(str, frequency: 0.3, spread: 0.8, seed: 1.1) ⇒ String

Generate rainbow-colored text using true color (24-bit) ANSI codes.

Examples:

puts Terminal::Ansi.rainbow('Hello, World!')

Parameters:

  • str (#to_s) —

    text to colorize

  • frequency (Float) (defaults to: 0.3) —

    color wave frequency

  • spread (Float) (defaults to: 0.8) —

    color wave spread

  • seed (Float) (defaults to: 1.1) —

    starting position in the color cycle

Returns:

  • (String) —

    text with per-character RGB foreground colors



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# File 'lib/terminal/ansi.rb', line 154

def rainbow(str, frequency: 0.3, spread: 0.8, seed: 1.1)
  pos = -1
  @pi2_third ||= 2.0 * Math::PI / 3.0
  @pi4_third ||= 4.0 * Math::PI / 3.0
  (
    str.to_s.chars.map! do |char|
      i = (seed + ((pos += 1) / spread)) * frequency
      "\e[38;2;#{(Math.sin(i) * 255).round.abs};#{
        (Math.sin(i + @pi2_third) * 255).round.abs
      };#{(Math.sin(i + @pi4_third) * 255).round.abs}m#{char}"
    end << RESET_FG
  ).join
end

.scale(text, scale: nil, width: nil, fracn: nil, fracd: nil, vertical: nil, horizontal: nil) ⇒ String

Note:

Only supported by Kitty.

Scale text using the text sizing protocol.

Examples:

Double-height Greeting

Terminal::Ansi.scale('Hello Ruby!', scale: 2)

Half-height Greeting

Terminal::Ansi.scale('Hello Ruby!', fracn: 1, fracd: 2, vertical: :middle)

Parameters:

  • text (#to_s) —

    text to scale

  • scale (Integer, nil) (defaults to: nil) —

    scale multiplier (1-7)

  • width (Integer, nil) (defaults to: nil) —

    width mode (0-7)

  • fracn (Integer, nil) (defaults to: nil) —

    fractional numerator (0-15)

  • fracd (Integer, nil) (defaults to: nil) —

    fractional denominator (must be > fracn, max 15)

  • vertical (Symbol, Integer, nil) (defaults to: nil) —

    vertical alignment: :top, :bottom, :middle

  • horizontal (Symbol, Integer, nil) (defaults to: nil) —

    horizontal alignment: :left, :right, :center

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 575

def scale(
  text,
  scale: nil,
  width: nil,
  fracn: nil,
  fracd: nil,
  vertical: nil,
  horizontal: nil
)
  opts = scale ? ["s=#{scale.clamp(1, 7)}"] : []
  opts << "w=#{width.clamp(0, 7)}" if width
  if fracn
    opts << "n=#{fracn = fracn.clamp(0, 15)}"
    opts << "d=#{fracd.clamp(fracn + 1, 15)}" if fracd
    case vertical
    when 0, :top
      opts << 'v=0'
    when 1, :bottom
      opts << 'v=1'
    when 2, :middle
      opts << 'v=2'
    end
    case horizontal
    when 0, :left
      opts << 'h=0'
    when 1, :right
      opts << 'h=1'
    when 2, :center
      opts << 'h=2'
    end
  end
  "\e]66;#{opts.join(':')};#{text}\a"
end

.screen_alternate ⇒ String

Switch to the alternate screen buffer.

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 427

def screen_alternate = +SCREEN_ALTERNATE

.screen_alternate_off ⇒ String

Switch back from the alternate screen buffer.

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 434

def screen_alternate_off = +SCREEN_ALTERNATE_OFF

.screen_erase(part = :all) ⇒ String

Erase part of the screen.

Parameters:

  • part (Symbol) (defaults to: :all) —

    area to erase: :all, :below, :above, or :scrollback

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 406

def screen_erase(part = :all) = "\e[#{@screen_erase[part]}J"

.screen_restore ⇒ String

Restore previously saved screen state.

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 420

def screen_restore = +SCREEN_RESTORE

.screen_save ⇒ String

Save screen state.

Returns:

  • (String) —

    ANSI escape sequence

See Also:



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# File 'lib/terminal/ansi.rb', line 413

def screen_save = +SCREEN_SAVE

.screen_scroll_down(lines = 1) ⇒ String

Scroll the screen down.

Parameters:

  • lines (Integer) (defaults to: 1) —

    number of lines

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 446

def screen_scroll_down(lines = 1) = "\e[#{lines}T"

.screen_scroll_up(lines = 1) ⇒ String

Scroll the screen up.

Parameters:

  • lines (Integer) (defaults to: 1) —

    number of lines

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 440

def screen_scroll_up(lines = 1) = "\e[#{lines}S"

.title(title) ⇒ String

Note:

Supported by Hyper, iTerm2, Kitty, macOS Terminal, Tabby, WezTerm.

Set the terminal window title.

Examples:

Terminal.raw_write(Terminal::Ansi.title('My App'))

Parameters:

  • title (String) —

    the title text

Returns:

  • (String) —

    ANSI escape sequence



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# File 'lib/terminal/ansi.rb', line 470

def title(title) = "\e]0;#{title}\a"

.try_convert(attributes, separator: ' ') ⇒ String?

Try to convert a space-separated attribute string to an ANSI escape sequence.

Examples:

Terminal::Ansi.try_convert('bold red')  # => "\e[1;31m"
Terminal::Ansi.try_convert('invalid')   # => nil

Parameters:

  • attributes (#to_s) —

    space-separated attribute names

  • separator (String) (defaults to: ' ') —

    delimiter for splitting

Returns:

  • (String, nil) —

    ANSI escape sequence, or nil if any attribute is invalid



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# File 'lib/terminal/ansi.rb', line 131

def try_convert(attributes, separator: ' ')
  return unless attributes
  cache = @convert_cache[separator]
  hit = cache[key = attributes.to_s] and return hit
  cache.clear if cache.size > 1024 # cache limit
  cache[key] = unless (attributes = key.split(separator)).empty?
    # attributes.uniq!
    codes = attributes.map { @attr_str_map[it] || break }
    "\e[#{codes.join(';')}m" if codes
  end
end

.unbbcode(str) ⇒ String

Remove BBCode tags from a string, keeping the enclosed text.

Examples:

Terminal::Ansi.unbbcode('[bold]Hello[/bold]') # => "Hello"

Parameters:

  • str (#to_s) —

    text with BBCode markup

Returns:

  • (String) —

    text with tags removed

See Also:



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# File 'lib/terminal/ansi.rb', line 211

def unbbcode(str)
  str = str.to_s
  return str.dup unless str.index('[')
  str.gsub(@re_bbcode) do |match_str|
    match = Regexp.last_match(1) or next match_str
    if match[0] == '\\'
      match[0] = ''
      next "[#{match}]"
    end
    next match_str if (match = match.split).empty?
    next if match.all? { @attr_str_map[it] }
    match_str
  end
end

.undecorate(str) ⇒ String

Remove all ANSI escape codes from a string.

Examples:

Terminal::Ansi.undecorate("\e[1;31mHello\e[m")
# => "Hello"

Parameters:

  • str (#to_s) —

    the string to clean

Returns:

  • (String) —

    a copy with all ANSI codes stripped



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# File 'lib/terminal/ansi.rb', line 116

def undecorate(str)
  (str = str.to_s).index("\e") ? str.gsub(@re_test, '') : str.dup
end

.valid?(*attributes) ⇒ true, false

Check whether all given attributes are valid.

Examples:

Terminal::Ansi.valid?(:bold, :red)  # => true
Terminal::Ansi.valid?(:nope)        # => false

Parameters:

  • attributes (Array<String, Symbol, Integer>) —

    attributes to validate

Returns:

  • (true, false) 


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# File 'lib/terminal/ansi.rb', line 275

def valid?(*attributes)
  attributes.all? do |arg|
    case arg
    when String
      @attr_str_map[arg]
    when Symbol
      @attr_sym_map[arg]
    when (0..767)
      true
    end
  end
end