Class: LuminosityContrast::Color

Inherits:
Object
  • Object
show all
Defined in:
lib/luminosity_contrast/color.rb

Overview

Color object parses RGB formats like hex code string or array of numbers. Populates RGB attributes and provides convenience methods for comparing colors. This class is used by LuminosityContrast.ratio but can also be used on its own.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Color

Returns a new instance of Color.

Parameters:

  • args —

    a representation of an RGB color

See Also:



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# File 'lib/luminosity_contrast/color.rb', line 20

def initialize(*args)
  input = args.size == 1 ? args[0] : args
  @r, @g, @b = Color.rgb_from(input)
end

Instance Attribute Details

#b ⇒ Float (readonly)

Returns the blue component.

Returns:

  • (Float) —

    the blue component



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# File 'lib/luminosity_contrast/color.rb', line 14

class Color

  attr_reader :r, :g, :b

  # @param args a representation of an RGB color
  # @see .rgb_from
  def initialize(*args)
    input = args.size == 1 ? args[0] : args
    @r, @g, @b = Color.rgb_from(input)
  end

  # @return [Float] between 0.0 and 1.0
  # @see LuminosityContrast.relative_luminance
  def relative_luminance
    LuminosityContrast.relative_luminance(r,g,b)
  end

  # @param color [Color] a second color contrasting with this one
  # @return [Float] a ratio between 1.0 and 21.0
  # @see LuminosityContrast.ratio
  def ratio(color)
    LuminosityContrast.ratio(self, color)
  end

  # @return [Array] red, green, blue color components from 0.0 to 255.0
  def to_rgb
    [r, g, b]
  end

  class << self
    # Convert one of several RGB formats to an Array of components
    # @return [Array] red, green, blue color components from 0.0 to 255.0
    # @param input a representation of an RGB color
    # @example 3 or 6 character hex color code String
    #   rgb_from('fff')
    #   rgb_from('000000')
    # @example Array with 3 numbers between 0 and 255
    #   rgb_from([0, 127.0, 255])
    # @example a Hash with 3 numbers between 0 and 255
    #   rgb_from(r: 0, g: 127.0, b: 255)
    # @example an Object that responds to methods #r, #g, #b
    #   color = Color.new('000')
    #   rgb_from(color)
    def rgb_from(input)
      case input
      when String # hex code
        raise 'Invalid hex code' unless input =~ /\A([0-9a-f]{3}){1,2}\z/i
        rgb = if input.size == 3
          input.split('').map { |h| h * 2 }
        else
          input.scan(/.{2}/)
        end
        rgb.map { |h| h.hex.to_i }
      when Array # array of numbers
        raise 'Invalid RGB array' unless input.size == 3
        input.map(&:to_f)
      when Hash
        rgb = input.values_at(:r, :g, :b)
        raise 'Invalid RGB hash' unless rgb.size == 3
        rgb.map(&:to_f)
      else
        methods = [:r,:g, :b]
        if methods.select { |m| input.respond_to?(m) }.size == methods.size
          methods.map { |m| input.send(m) }
        else
          raise 'Invalid input'
        end
      end
    end

  end
end

#g ⇒ Float (readonly)

Returns the green component.

Returns:

  • (Float) —

    the green component



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# File 'lib/luminosity_contrast/color.rb', line 14

class Color

  attr_reader :r, :g, :b

  # @param args a representation of an RGB color
  # @see .rgb_from
  def initialize(*args)
    input = args.size == 1 ? args[0] : args
    @r, @g, @b = Color.rgb_from(input)
  end

  # @return [Float] between 0.0 and 1.0
  # @see LuminosityContrast.relative_luminance
  def relative_luminance
    LuminosityContrast.relative_luminance(r,g,b)
  end

  # @param color [Color] a second color contrasting with this one
  # @return [Float] a ratio between 1.0 and 21.0
  # @see LuminosityContrast.ratio
  def ratio(color)
    LuminosityContrast.ratio(self, color)
  end

  # @return [Array] red, green, blue color components from 0.0 to 255.0
  def to_rgb
    [r, g, b]
  end

  class << self
    # Convert one of several RGB formats to an Array of components
    # @return [Array] red, green, blue color components from 0.0 to 255.0
    # @param input a representation of an RGB color
    # @example 3 or 6 character hex color code String
    #   rgb_from('fff')
    #   rgb_from('000000')
    # @example Array with 3 numbers between 0 and 255
    #   rgb_from([0, 127.0, 255])
    # @example a Hash with 3 numbers between 0 and 255
    #   rgb_from(r: 0, g: 127.0, b: 255)
    # @example an Object that responds to methods #r, #g, #b
    #   color = Color.new('000')
    #   rgb_from(color)
    def rgb_from(input)
      case input
      when String # hex code
        raise 'Invalid hex code' unless input =~ /\A([0-9a-f]{3}){1,2}\z/i
        rgb = if input.size == 3
          input.split('').map { |h| h * 2 }
        else
          input.scan(/.{2}/)
        end
        rgb.map { |h| h.hex.to_i }
      when Array # array of numbers
        raise 'Invalid RGB array' unless input.size == 3
        input.map(&:to_f)
      when Hash
        rgb = input.values_at(:r, :g, :b)
        raise 'Invalid RGB hash' unless rgb.size == 3
        rgb.map(&:to_f)
      else
        methods = [:r,:g, :b]
        if methods.select { |m| input.respond_to?(m) }.size == methods.size
          methods.map { |m| input.send(m) }
        else
          raise 'Invalid input'
        end
      end
    end

  end
end

#r ⇒ Float (readonly)

Returns the red component.

Returns:

  • (Float) —

    the red component



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# File 'lib/luminosity_contrast/color.rb', line 14

class Color

  attr_reader :r, :g, :b

  # @param args a representation of an RGB color
  # @see .rgb_from
  def initialize(*args)
    input = args.size == 1 ? args[0] : args
    @r, @g, @b = Color.rgb_from(input)
  end

  # @return [Float] between 0.0 and 1.0
  # @see LuminosityContrast.relative_luminance
  def relative_luminance
    LuminosityContrast.relative_luminance(r,g,b)
  end

  # @param color [Color] a second color contrasting with this one
  # @return [Float] a ratio between 1.0 and 21.0
  # @see LuminosityContrast.ratio
  def ratio(color)
    LuminosityContrast.ratio(self, color)
  end

  # @return [Array] red, green, blue color components from 0.0 to 255.0
  def to_rgb
    [r, g, b]
  end

  class << self
    # Convert one of several RGB formats to an Array of components
    # @return [Array] red, green, blue color components from 0.0 to 255.0
    # @param input a representation of an RGB color
    # @example 3 or 6 character hex color code String
    #   rgb_from('fff')
    #   rgb_from('000000')
    # @example Array with 3 numbers between 0 and 255
    #   rgb_from([0, 127.0, 255])
    # @example a Hash with 3 numbers between 0 and 255
    #   rgb_from(r: 0, g: 127.0, b: 255)
    # @example an Object that responds to methods #r, #g, #b
    #   color = Color.new('000')
    #   rgb_from(color)
    def rgb_from(input)
      case input
      when String # hex code
        raise 'Invalid hex code' unless input =~ /\A([0-9a-f]{3}){1,2}\z/i
        rgb = if input.size == 3
          input.split('').map { |h| h * 2 }
        else
          input.scan(/.{2}/)
        end
        rgb.map { |h| h.hex.to_i }
      when Array # array of numbers
        raise 'Invalid RGB array' unless input.size == 3
        input.map(&:to_f)
      when Hash
        rgb = input.values_at(:r, :g, :b)
        raise 'Invalid RGB hash' unless rgb.size == 3
        rgb.map(&:to_f)
      else
        methods = [:r,:g, :b]
        if methods.select { |m| input.respond_to?(m) }.size == methods.size
          methods.map { |m| input.send(m) }
        else
          raise 'Invalid input'
        end
      end
    end

  end
end

Class Method Details

.rgb_from(input) ⇒ Array

Convert one of several RGB formats to an Array of components

Examples:

3 or 6 character hex color code String

rgb_from('fff')
rgb_from('000000')

Array with 3 numbers between 0 and 255

rgb_from([0, 127.0, 255])

a Hash with 3 numbers between 0 and 255

rgb_from(r: 0, g: 127.0, b: 255)

an Object that responds to methods #r, #g, #b

color = Color.new('000')
rgb_from(color)

Parameters:

  • input —

    a representation of an RGB color

Returns:

  • (Array) —

    red, green, blue color components from 0.0 to 255.0



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# File 'lib/luminosity_contrast/color.rb', line 57

def rgb_from(input)
  case input
  when String # hex code
    raise 'Invalid hex code' unless input =~ /\A([0-9a-f]{3}){1,2}\z/i
    rgb = if input.size == 3
      input.split('').map { |h| h * 2 }
    else
      input.scan(/.{2}/)
    end
    rgb.map { |h| h.hex.to_i }
  when Array # array of numbers
    raise 'Invalid RGB array' unless input.size == 3
    input.map(&:to_f)
  when Hash
    rgb = input.values_at(:r, :g, :b)
    raise 'Invalid RGB hash' unless rgb.size == 3
    rgb.map(&:to_f)
  else
    methods = [:r,:g, :b]
    if methods.select { |m| input.respond_to?(m) }.size == methods.size
      methods.map { |m| input.send(m) }
    else
      raise 'Invalid input'
    end
  end
end

Instance Method Details

#ratio(color) ⇒ Float

Returns a ratio between 1.0 and 21.0.

Parameters:

  • color (Color) —

    a second color contrasting with this one

Returns:

  • (Float) —

    a ratio between 1.0 and 21.0

See Also:



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# File 'lib/luminosity_contrast/color.rb', line 34

def ratio(color)
  LuminosityContrast.ratio(self, color)
end

#relative_luminance ⇒ Float

Returns between 0.0 and 1.0.

Returns:

  • (Float) —

    between 0.0 and 1.0

See Also:



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# File 'lib/luminosity_contrast/color.rb', line 27

def relative_luminance
  LuminosityContrast.relative_luminance(r,g,b)
end

#to_rgb ⇒ Array

Returns red, green, blue color components from 0.0 to 255.0.

Returns:

  • (Array) —

    red, green, blue color components from 0.0 to 255.0



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# File 'lib/luminosity_contrast/color.rb', line 39

def to_rgb
  [r, g, b]
end