Class: Termin::ANSIColor::RGBColorMetrics::CIELab::CIELabTriple

Inherits:
Struct
  • Object
show all
Extended by:
Termin::ANSIColor::RGBColorMetricsHelpers::NormalizeRGBTriple
Includes:
Termin::ANSIColor::RGBColorMetricsHelpers::WeightedEuclideanDistance
Defined in:
lib/termin/ansicolor/rgb_color_metrics.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Methods included from Termin::ANSIColor::RGBColorMetricsHelpers::WeightedEuclideanDistance

#weighted_euclidean_distance_to

Instance Attribute Details

#a ⇒ Object

Returns the value of attribute a

Returns:

  • (Object) —

    the current value of a



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# File 'lib/termin/ansicolor/rgb_color_metrics.rb', line 123

def a
  @a
end

#b ⇒ Object

Returns the value of attribute b

Returns:

  • (Object) —

    the current value of b



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# File 'lib/termin/ansicolor/rgb_color_metrics.rb', line 123

def b
  @b
end

#l ⇒ Object

Returns the value of attribute l

Returns:

  • (Object) —

    the current value of l



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# File 'lib/termin/ansicolor/rgb_color_metrics.rb', line 123

def l
  @l
end

Class Method Details

.from_rgb_triple(rgb_triple) ⇒ Object 



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# File 'lib/termin/ansicolor/rgb_color_metrics.rb', line 127

def self.from_rgb_triple(rgb_triple)
  r, g, b = normalize_rgb_triple rgb_triple

  x =  0.436052025 * r + 0.385081593 * g + 0.143087414 * b
  y =  0.222491598 * r + 0.71688606  * g + 0.060621486 * b
  z =  0.013929122 * r + 0.097097002 * g + 0.71418547  * b

  xr = x / 0.964221
  yr = y
  zr = z / 0.825211

  eps = 216.0 / 24389
  k = 24389.0 / 27

  fx = xr > eps ? xr ** (1.0 / 3) : (k * xr + 16) / 116
  fy = yr > eps ? yr ** (1.0 / 3) : (k * yr + 16) / 116
  fz = zr > eps ? zr ** (1.0 / 3) : (k * zr + 16) / 116

  l = 2.55 * ((116 * fy) - 16)
  a = 500 * (fx - fy)
  b = 200 * (fy - fz)

  new(l.round, a.round, b.round)
end