Module: Rich::Palettes

Defined in:
lib/rich/_palettes.rb

Overview

Color palette definitions for terminal color systems. Provides lookup tables for standard 16-color, 256-color (8-bit), and Windows console color palettes.

Constant Summary collapse

STANDARD_PALETTE =

Standard 16-color ANSI palette (colors 0-15) These are the typical default colors, but terminals may customize them

[
  ColorTriplet.new(0, 0, 0),        # 0: Black
  ColorTriplet.new(128, 0, 0),      # 1: Red
  ColorTriplet.new(0, 128, 0),      # 2: Green
  ColorTriplet.new(128, 128, 0),    # 3: Yellow
  ColorTriplet.new(0, 0, 128),      # 4: Blue
  ColorTriplet.new(128, 0, 128),    # 5: Magenta
  ColorTriplet.new(0, 128, 128),    # 6: Cyan
  ColorTriplet.new(192, 192, 192),  # 7: White
  ColorTriplet.new(128, 128, 128),  # 8: Bright Black (Gray)
  ColorTriplet.new(255, 0, 0),      # 9: Bright Red
  ColorTriplet.new(0, 255, 0),      # 10: Bright Green
  ColorTriplet.new(255, 255, 0),    # 11: Bright Yellow
  ColorTriplet.new(0, 0, 255),      # 12: Bright Blue
  ColorTriplet.new(255, 0, 255),    # 13: Bright Magenta
  ColorTriplet.new(0, 255, 255),    # 14: Bright Cyan
  ColorTriplet.new(255, 255, 255)   # 15: Bright White
].freeze
WINDOWS_PALETTE =

Windows Console palette (slightly different from ANSI standard)

[
  ColorTriplet.new(12, 12, 12),     # 0: Black
  ColorTriplet.new(197, 15, 31),    # 1: Red
  ColorTriplet.new(19, 161, 14),    # 2: Green
  ColorTriplet.new(193, 156, 0),    # 3: Yellow
  ColorTriplet.new(0, 55, 218),     # 4: Blue
  ColorTriplet.new(136, 23, 152),   # 5: Magenta
  ColorTriplet.new(58, 150, 221),   # 6: Cyan
  ColorTriplet.new(204, 204, 204),  # 7: White
  ColorTriplet.new(118, 118, 118),  # 8: Bright Black (Gray)
  ColorTriplet.new(231, 72, 86),    # 9: Bright Red
  ColorTriplet.new(22, 198, 12),    # 10: Bright Green
  ColorTriplet.new(249, 241, 165),  # 11: Bright Yellow
  ColorTriplet.new(59, 120, 255),   # 12: Bright Blue
  ColorTriplet.new(180, 0, 158),    # 13: Bright Magenta
  ColorTriplet.new(97, 214, 214),   # 14: Bright Cyan
  ColorTriplet.new(242, 242, 242)   # 15: Bright White
].freeze
EIGHT_BIT_PALETTE =

Generate the 256-color (8-bit) palette Colors 0-15: Standard colors Colors 16-231: 6x6x6 color cube Colors 232-255: Grayscale ramp

begin
  palette = []

  # Colors 0-15: Standard palette
  STANDARD_PALETTE.each { |color| palette << color }

  # Colors 16-231: 6x6x6 color cube
  # Each component can be 0, 95, 135, 175, 215, or 255
  cube_values = [0, 95, 135, 175, 215, 255]
  (0...6).each do |r|
    (0...6).each do |g|
      (0...6).each do |b|
        palette << ColorTriplet.new(cube_values[r], cube_values[g], cube_values[b])
      end
    end
  end

  # Colors 232-255: Grayscale ramp (24 shades, excluding black and white)
  (0...24).each do |i|
    gray = 8 + i * 10
    palette << ColorTriplet.new(gray, gray, gray)
  end

  palette.freeze
end

Class Method Summary collapse

Class Method Details

.get_eight_bit(index) ⇒ ColorTriplet

Get a color from the 8-bit palette

Parameters:

  • index (Integer) —

    Color index (0-255)

Returns:



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# File 'lib/rich/_palettes.rb', line 129

def get_eight_bit(index)
  EIGHT_BIT_PALETTE[index.clamp(0, 255)]
end

.get_standard(index) ⇒ ColorTriplet

Get a color from the standard palette

Parameters:

  • index (Integer) —

    Color index (0-15)

Returns:



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# File 'lib/rich/_palettes.rb', line 136

def get_standard(index)
  STANDARD_PALETTE[index.clamp(0, 15)]
end

.get_windows(index) ⇒ ColorTriplet

Get a color from the Windows palette

Parameters:

  • index (Integer) —

    Color index (0-15)

Returns:



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# File 'lib/rich/_palettes.rb', line 143

def get_windows(index)
  WINDOWS_PALETTE[index.clamp(0, 15)]
end

.match_color(triplet, palette: EIGHT_BIT_PALETTE, start_index: 0, end_index: nil) ⇒ Integer

Find the closest color in a palette

Parameters:

  • triplet (ColorTriplet) —

    Color to match

  • palette (Array<ColorTriplet>) (defaults to: EIGHT_BIT_PALETTE) —

    Palette to search

  • start_index (Integer) (defaults to: 0) —

    Starting index in palette

  • end_index (Integer) (defaults to: nil) —

    Ending index in palette (exclusive)

Returns:

  • (Integer) —

    Index of closest matching color



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# File 'lib/rich/_palettes.rb', line 88

def match_color(triplet, palette: EIGHT_BIT_PALETTE, start_index: 0, end_index: nil)
  end_index ||= palette.length

  best_index = start_index
  best_distance = Float::INFINITY

  (start_index...end_index).each do |i|
    distance = triplet.weighted_distance(palette[i])
    if distance < best_distance
      best_distance = distance
      best_index = i
    end
  end

  best_index
end

.match_eight_bit(triplet) ⇒ Integer

Match to 8-bit palette (256 colors)

Parameters:

Returns:

  • (Integer) —

    8-bit color index (0-255)



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# File 'lib/rich/_palettes.rb', line 115

def match_eight_bit(triplet)
  match_color(triplet, palette: EIGHT_BIT_PALETTE, start_index: 0, end_index: 256)
end

.match_standard(triplet) ⇒ Integer

Match to standard 16-color palette

Parameters:

Returns:

  • (Integer) —

    Standard color index (0-15)



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# File 'lib/rich/_palettes.rb', line 108

def match_standard(triplet)
  match_color(triplet, palette: STANDARD_PALETTE, start_index: 0, end_index: 16)
end

.match_windows(triplet) ⇒ Integer

Match to Windows console palette

Parameters:

Returns:

  • (Integer) —

    Windows color index (0-15)



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# File 'lib/rich/_palettes.rb', line 122

def match_windows(triplet)
  match_color(triplet, palette: WINDOWS_PALETTE, start_index: 0, end_index: 16)
end