Class: Color::Grayscale

Inherits:
Data
  • Object
show all
Includes:
Color
Defined in:
lib/color/grayscale.rb,
lib/color.rb

Overview

Grayscale is a color object representing shades of gray as a ratio of black to white, where 0% (0.0) gray is black and 100% (1.0) gray is white.

Grayscale colors are immutable Data class instances. Array deconstruction is ‘[gray]` and hash deconstruction is `gray:`. See #g, #gray.

Constant Summary

Constants included from Color

EPSILON, TOLERANCE, VERSION

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Color

#==, #css_value, #map, #map_with, normalize, #scale, translate_range, #zip

Constructor Details

#initialize(g:) ⇒ Grayscale

Creates a grayscale color object from a fractional value (0.0 .. 1.0).

“‘ruby Color::Grayscale.from_fraction(0.5) Color::Grayscale.new(0.5) Color::Grayscale[g: 0.5] “`



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# File 'lib/color/grayscale.rb', line 65

def initialize(g:)
  super(g: normalize(g))
end

Instance Attribute Details

#g ⇒ Object (readonly) Also known as: brightness

Returns the value of attribute g

Returns:

  • (Object) —

    the current value of g



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# File 'lib/color.rb', line 46

def g
  @g
end

Class Method Details

.from_percentage(*args, **kwargs) ⇒ Object Also known as: from_values

Creates a grayscale color object from a percentage value (0.0 .. 100.0).

“‘ruby Color::Grayscale.from_percentage(50) # => Grayscale [0.50%] Color::Grayscale.from_values(50) # => Grayscale [0.50%] “`

:call-seq:

from_percentage(g)
from_percentage(g:)
from_values(g)
from_values(g:)



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# File 'lib/color/grayscale.rb', line 37

def self.from_percentage(*args, **kwargs)
  g =
    case [args, kwargs]
    in [[g], {}]
      g
    in [[], {g:}]
      g
    else
      new(*args, **kwargs)
    end

  new(g: g / 100.0)
end

Instance Method Details

#coerce(other) ⇒ Object

Coerces the other Color object to grayscale.



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# File 'lib/color/grayscale.rb', line 71

def coerce(other) = other.to_grayscale

#components ⇒ Object

:nodoc:



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# File 'lib/color/grayscale.rb', line 168

def components = 1 # :nodoc:

#css(alpha: nil) ⇒ Object

Present the color as a CSS ‘rgb` color with optional `alpha`.

“‘ruby Color::Grayscale.css # => rgb(50.00% 50.00% 50.00%) Color::Grayscale.css(alpha: 0.75) # => rgb(50.00% 50.00% 50.00% / 0.75) “`



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# File 'lib/color/grayscale.rb', line 122

def css(alpha: nil)
  params = ([css_value(gray, :percent)] * 3).join(" ")
  params = "#{params} / #{css_value(alpha)}" if alpha

  "rgb(#{params})"
end

#darken_by(percent) ⇒ Object

Darken the grayscale color by the stated percent.



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# File 'lib/color/grayscale.rb', line 135

def darken_by(percent) = Color::Grayscale.from_fraction([g - (g * (percent / 100.0)), 0.0].max)

#deconstruct_keys(_keys) ⇒ Object 



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# File 'lib/color/grayscale.rb', line 162

def deconstruct_keys(_keys) = {g:, gray:}

#gray ⇒ Object 



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# File 'lib/color/grayscale.rb', line 141

def gray = g * 100.0

#html ⇒ Object

Present the color as an HTML/CSS color string (e.g., ‘#dddddd`).



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# File 'lib/color/grayscale.rb', line 111

def html
  "##{("%02x" % translate_range(g, to: 0.0..255.0)) * 3}"
end

#inspect ⇒ Object

:nodoc:



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# File 'lib/color/grayscale.rb', line 144

def inspect = "Grayscale [%.2f%%]" % [gray] # :nodoc:

#lighten_by(percent) ⇒ Object

Lightens the grayscale color by the stated percent.



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# File 'lib/color/grayscale.rb', line 131

def lighten_by(percent) = Color::Grayscale.from_fraction([g + (g * (percent / 100.0)), 1.0].min)

#pretty_print(q) ⇒ Object

:nodoc:



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# File 'lib/color/grayscale.rb', line 147

def pretty_print(q) # :nodoc:
  q.text "Grayscale"
  q.breakable
  q.group 2, "[", "]" do
    q.text "%.2f%%" % gray
  end
end

#to_a ⇒ Object Also known as: deconstruct

:nodoc:



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# File 'lib/color/grayscale.rb', line 156

def to_a = [gray] # :nodoc:

#to_cmyk ⇒ Object

Convert Grayscale to Color::CMYK.



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# File 'lib/color/grayscale.rb', line 75

def to_cmyk(...) = Color::CMYK.from_fraction(0, 0, 0, 1.0 - g.to_f)

#to_grayscale ⇒ Object 



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# File 'lib/color/grayscale.rb', line 82

def to_grayscale(...) = self

#to_hsl ⇒ Object

Converts Grayscale to Color::HSL.



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# File 'lib/color/grayscale.rb', line 103

def to_hsl(...) = Color::HSL.from_fraction(0, 0, g)

#to_internal ⇒ Object

:nodoc:



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# File 'lib/color/grayscale.rb', line 165

def to_internal = [g] # :nodoc:

#to_lab ⇒ Object

Converts Grayscale to Color::CIELAB via Color::RGB.



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# File 'lib/color/grayscale.rb', line 107

def to_lab(...) = to_rgb(...).to_lab(...)

#to_rgb ⇒ Object

Convert Grayscale to Color::RGB.



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# File 'lib/color/grayscale.rb', line 79

def to_rgb(...) = Color::RGB.from_fraction(g, g, g)

#to_xyz ⇒ Object

Converts Grayscale to Color::XYZ via Color::RGB.



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# File 'lib/color/grayscale.rb', line 86

def to_xyz(...) = to_rgb(...).to_xyz(...)

#to_yiq ⇒ Object

Convert Grayscale to Color::YIQ.

This approximates the actual value, as I and Q are calculated by treating the grayscale value as a RGB value. The Y (intensity or brightness) value is the same as the grayscale value.



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# File 'lib/color/grayscale.rb', line 94

def to_yiq(...)
  y = g
  i = (g * 0.596) + (g * -0.275) + (g * -0.321)
  q = (g * 0.212) + (g * -0.523) + (g * 0.311)
  Color::YIQ.from_fraction(y, i, q)
end