Class: Compass::Colors::HSL

Inherits:
Object
  • Object
show all
Defined in:
lib/compass-colors/hsl.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(h, s, l) ⇒ HSL

Returns a new instance of HSL.



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# File 'lib/compass-colors/hsl.rb', line 53

def initialize(h, s, l)
  self.h = h
  self.s = s
  self.l = l
end

Instance Attribute Details

#h ⇒ Object

Stored in degrees [0, 360)



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# File 'lib/compass-colors/hsl.rb', line 6

def h
  @h
end

#l ⇒ Object

Stored as a number from [0,1]



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# File 'lib/compass-colors/hsl.rb', line 8

def l
  @l
end

#s ⇒ Object

Stored as a number from [0,1]



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# File 'lib/compass-colors/hsl.rb', line 8

def s
  @s
end

Class Method Details

.from_color(color) ⇒ Object 



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# File 'lib/compass-colors/hsl.rb', line 10

def self.from_color(color)
  rgb = color.respond_to?(:rgb) ? color.rgb : color.value
  from_rgb(*rgb)
end

.from_fractions(hue, saturation, lightness) ⇒ Object 



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# File 'lib/compass-colors/hsl.rb', line 49

def self.from_fractions(hue, saturation, lightness)
  HSL.new(360 * hue, saturation, lightness)
end

.from_rgb(r, g, b) ⇒ Object 



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# File 'lib/compass-colors/hsl.rb', line 15

def self.from_rgb(r, g, b)
  rgb = [r,g,b]
  rgb.map!{|c| c / 255.0}
  min_rgb = rgb.min
  max_rgb = rgb.max
  delta = max_rgb - min_rgb

  lightness = (max_rgb + min_rgb) / 2.0

  if delta < 1e-5
     hue = 0
     saturation = 0
  else
     saturation = if ( lightness < 0.5 )
        delta / ( max_rgb + min_rgb )
     else
       delta / ( 2 - max_rgb - min_rgb )
     end

     deltas = rgb.map{|c| (((max_rgb - c) / 6.0) + (delta / 2.0)) / delta}

     hue = if (rgb[0] - max_rgb).abs < 1e-5
       deltas[2] - deltas[1]
     elsif (rgb[1] - max_rgb).abs < 1e-5
       ( 1.0 / 3.0 ) + deltas[0] - deltas[2]
     else
       ( 2.0 / 3.0 ) + deltas[1] - deltas[0]
     end
     hue += 1 if hue < 0
     hue -= 1 if hue > 1
   end
   from_fractions(hue, saturation, lightness)
end

Instance Method Details

#to_color ⇒ Object 



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# File 'lib/compass-colors/hsl.rb', line 59

def to_color
  m2 = l <= 0.5 ? l * (s + 1) : l + s - l * s
  m1 = l * 2 - m2
  Sass::Script::Color.new([hue_to_rgb(m1, m2, hp + 1.0/3),
                           hue_to_rgb(m1, m2, hp),
                           hue_to_rgb(m1, m2, hp - 1.0/3)].map { |c| (c * 0xff).round })
end