Class: Color::RGB

Inherits:
Object
  • Object
show all
Includes:
Loggable
Defined in:
lib/color/rgb.rb

Constant Summary collapse

RGB_VALUES = 
'([0-9a-f]{2})'
RRGGBB_REGEXP =

not supported, although in CSS: RGB_REGEXP = Regexp.new ‘(’ + RGB_VALUES + ‘)3’, Regexp::IGNORECASE

Regexp.new '^\#?' + (RGB_VALUES * 3) + '$', Regexp::IGNORECASE

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(red, green, blue) ⇒ RGB

Returns a new instance of RGB.



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# File 'lib/color/rgb.rb', line 48

def initialize(red, green, blue)
  [ [ red, "red" ], [ green, "green" ], [ blue, "blue" ] ].each do |val, str|
    Color::check_constraint(val, str, 0, 255)
  end

  @red   = red.to_i
  @green = green.to_i
  @blue  = blue.to_i
end

Instance Attribute Details

#blue ⇒ Object

Returns the value of attribute blue.



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

def blue
  @blue
end

#green ⇒ Object

Returns the value of attribute green.



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

def green
  @green
end

#red ⇒ Object

Returns the value of attribute red.



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

def red
  @red
end

Class Method Details

.matches_rgb_string?(val) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/color/rgb.rb', line 43

def matches_rgb_string?(val)
  val.kind_of?(String) && RRGGBB_REGEXP.match(val)
end

.new(*args) ⇒ Object 



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# File 'lib/color/rgb.rb', line 22

def new(*args)
  if args
    if args.size == 3
      new_orig(*args)
    elsif args.size == 1 and args[0].kind_of? String
      str = args[0].sub(%r{^\#}, '') # optional
      # str.hex does not validate, so we do here:
      if md = matches_rgb_string?(str)
        r, g, b = (1 .. 3).collect { |idx| md[idx].hex }
        new_orig r, g, b
      else
        raise RuntimeError.new("invalid RGB string '#{str}: does not match #{RRGGBB_REGEXP.source}")
      end
    else
      raise RuntimeError.new("invalid arguments '#{args.inspect}': expecting 0, 1, or 3")
    end
  else
    new_orig 0, 0, 0
  end
end

.new_orig ⇒ Object 



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# File 'lib/color/rgb.rb', line 21

alias_method :new_orig, :new

Instance Method Details

#<=>(other) ⇒ Object 



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# File 'lib/color/rgb.rb', line 66

def <=>(other)
  to_i <=> other.to_i
end

#==(other) ⇒ Object 



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# File 'lib/color/rgb.rb', line 70

def ==(other)
  to_i == other.to_i
end

#to_hsb ⇒ Object

Converts RGB to an HSB object.



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

def to_hsb
  # this is not the only implementation of RGB to HSB, but it works.

  # scale from 0..255 to 0..1
  r, g, b = [ red, green, blue ].collect { |v| v / 255.0 }

  log "r", r
  log "g", g
  log "b", b
  
  minrgb = [ r, g, b ].min
  log "minrgb", minrgb
  maxrgb = [ r, g, b ].max
  log "maxrgb", maxrgb
  delta  = maxrgb - minrgb
  log "delta", delta
  
  hue = nil
  saturation = nil
  brightness = maxrgb
  
  if delta == 0
    # this is a gray, no chroma...
    hue = 0
    saturation = 0
  else                        # chromatic data...
    saturation = delta / maxrgb

    del_red, del_green, del_blue = [ r, g, b ].collect do |v|
      (((maxrgb - v) / 6.0) + (delta / 2.0)) / delta
    end
    
    if r == maxrgb
      hue = del_blue - del_green
    elsif g == maxrgb
      hue = (1.0 / 3) + del_red - del_blue
    elsif b == maxrgb
      hue = (2.0 / 3) + del_green - del_red
    end
    
    if hue < 0
      hue += 1
    end
    
    if hue > 1
      hue -= 1
    end
  end

  log "hue", hue
  log "saturation", saturation
  log "brightness", brightness
  
  # hue is to one decimal place; saturation and brightness to three
  Color::HSB.new Color::round(hue * 360, 1), Color::round(saturation, 3), Color::round(brightness, 3)
end

#to_i ⇒ Object 



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# File 'lib/color/rgb.rb', line 62

def to_i
  (red << 16) | (green << 8) | blue
end

#to_s ⇒ Object 



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# File 'lib/color/rgb.rb', line 58

def to_s
  "#{red},#{green},#{blue}"
end