Class: Color

Inherits:
Object show all
Defined in:
lib/iron/web/color.rb

Overview

Implements a color (r,g,b + a) with conversion to/from web format (eg #aabbcc), and with a number of utilities to lighten, darken and blend values.

Constant Summary collapse

HEXVAL =

Table for conversion to hex

(('0'..'9').to_a).concat(('A'..'F').to_a).freeze
BRIGHTNESS_DEFAULT =

Default value for #darken, #lighten etc.

0.2
WHITE =

Some constants for general use

Color.new(255,255,255).freeze
BLACK = 
Color.new(0,0,0).freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Color

Construct ourselves from whatever is passed in



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# File 'lib/iron/web/color.rb', line 15

def initialize(*args)
  @r = 255
  @g = 255
  @b = 255
  @a = 255

  if args.size.between?(3,4)
    self.r = args[0]
    self.g = args[1]
    self.b = args[2]
    self.a = args[3] if args[3]
  else
    set(*args)
  end
end

Instance Attribute Details

#a ⇒ Object

Basic attributes - holds each channel as 0-255 fixnum



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# File 'lib/iron/web/color.rb', line 7

def a
  @a
end

#b ⇒ Object

Basic attributes - holds each channel as 0-255 fixnum



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# File 'lib/iron/web/color.rb', line 7

def b
  @b
end

#g ⇒ Object

Basic attributes - holds each channel as 0-255 fixnum



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# File 'lib/iron/web/color.rb', line 7

def g
  @g
end

#r ⇒ Object

Basic attributes - holds each channel as 0-255 fixnum



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# File 'lib/iron/web/color.rb', line 7

def r
  @r
end

Class Method Details

.average(col1, col2) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 229

def self.average(col1, col2)
  self.blend(col1, col2, 0.5)
end

.blend(col1, col2, amt) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 223

def self.blend(col1, col2, amt)
  col1 = Color.parse(col1)
  col2 = Color.parse(col2)
  col1.blend(col2, amt)
end

.lookup_callback ⇒ Object

Get the lookup callback, if any



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# File 'lib/iron/web/color.rb', line 65

def self.lookup_callback
  @lookup_callback
end

.lookup_callback=(callback) ⇒ Object

Assigns a callback lambda to convert symbols into parse-able values. Sample usage:

Color.lookup_callback = lambda {|val| Settings[:site][:colors].get!(val) }
rgb(:off_white)  # => '#f8f0ee'



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# File 'lib/iron/web/color.rb', line 60

def self.lookup_callback=(callback)
  @lookup_callback = callback
end

.parse(*args) ⇒ Object

Attempt to read in a string and parse it into values



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# File 'lib/iron/web/color.rb', line 70

def self.parse(*args)
  case args.size

  when 0 then
    return nil

  when 1 then
    val = args[0]

    # Trivial parse... :-)
    return val if val.is_a?(Color)

    # Lookup site settings if symbol
    if val.is_a?(Symbol)
      callback = Color.lookup_callback
      return callback.nil? ? nil : self.parse(callback.call(val))
    end

    # Single value, assume grayscale
    return Color.new(val, val, val) if val.is_a?(Fixnum)

    # Assume string
    str = val.to_s.upcase
    str = str[/[0-9A-F]{3,8}/] || ''
    case str.size
    when 3, 4 then
      r, g, b, a = str.scan(/[0-9A-F]/)
    when 6, 8 then
      r, g, b, a = str.scan(/[0-9A-F]{2}/)
    else
      return nil
    end
    a = 255 if a.nil?

    return Color.new(r,g,b,a)

  when 3,4 then
    return Color.new(*args)

  end
  nil
end

Instance Method Details

#==(val) ⇒ Object

Test for equality, accepts string vals as well, eg Color.new(‘aaa’) == ‘#AAAAAA’ => true



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# File 'lib/iron/web/color.rb', line 44

def ==(val)
  val = Color.parse(val)
  return false if val.nil?
  return r == val.r && g == val.g && b == val.b && a == val.a
end

#blend(other, amt) ⇒ Object

Blend to a color amt % towards another color value



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# File 'lib/iron/web/color.rb', line 207

def blend(other, amt)
  other = Color.parse(other)
  return Color.new(self) if amt <= 0 || other.nil?
  return Color.new(other) if amt >= 1.0
  val = Color.new(self)
  val.r += ((other.r - val.r)*amt).to_i
  val.g += ((other.g - val.g)*amt).to_i
  val.b += ((other.b - val.b)*amt).to_i
  val
end

#blend!(other, amt) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 218

def blend!(other, amt)
  set(blend(other, amt))
  self
end

#brightness ⇒ Object

Compute our overall brightness, using perception-based weighting, from 0.0 to 1.0



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# File 'lib/iron/web/color.rb', line 189

def brightness
  (0.2126 * self.r + 0.7152 * self.g + 0.0722 * self.b) / 255.0
end

#contrast(amt = BRIGHTNESS_DEFAULT) ⇒ Object

Go towards middle of brightness scale, based on whether color is dark or light.



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# File 'lib/iron/web/color.rb', line 174

def contrast(amt = BRIGHTNESS_DEFAULT)
  dark? ? lighten(amt) : darken(amt)
end

#contrast!(amt = BRIGHTNESS_DEFAULT) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 178

def contrast!(amt = BRIGHTNESS_DEFAULT)
  set(contrast(amt))
  self
end

#dark? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/iron/web/color.rb', line 193

def dark?
  brightness < 0.5
end

#darken(amt = BRIGHTNESS_DEFAULT) ⇒ Object

Darken color by amt



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# File 'lib/iron/web/color.rb', line 158

def darken(amt = BRIGHTNESS_DEFAULT)
  return self if amt <= 0
  return BLACK if amt >= 1.0
  val = Color.new(self)
  val.r -= (val.r * amt).to_i
  val.g -= (val.g * amt).to_i
  val.b -= (val.b * amt).to_i
  val
end

#darken!(amt = BRIGHTNESS_DEFAULT) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 168

def darken!(amt = BRIGHTNESS_DEFAULT)
  set(darken(amt))
  self
end

#grayscale ⇒ Object

Convert to grayscale



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# File 'lib/iron/web/color.rb', line 184

def grayscale
  Color.new(self.brightness)
end

#grayscale! ⇒ Object 



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# File 'lib/iron/web/color.rb', line 201

def grayscale!
  set(grayscale)
  self
end

#grayscale? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/iron/web/color.rb', line 137

def grayscale?
  @r == @g && @g == @b
end

#inspect ⇒ Object 



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# File 'lib/iron/web/color.rb', line 113

def inspect
  to_s
end

#light? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/iron/web/color.rb', line 197

def light?
  !dark?
end

#lighten(amt = BRIGHTNESS_DEFAULT) ⇒ Object

Lighten color by amt



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# File 'lib/iron/web/color.rb', line 142

def lighten(amt = BRIGHTNESS_DEFAULT)
  return self if amt <= 0
  return WHITE if amt >= 1.0
  val = Color.new(self)
  val.r += ((255-val.r) * amt).to_i
  val.g += ((255-val.g) * amt).to_i
  val.b += ((255-val.b) * amt).to_i
  val
end

#lighten!(amt = BRIGHTNESS_DEFAULT) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 152

def lighten!(amt = BRIGHTNESS_DEFAULT)
  set(lighten(amt))
  self
end

#opaque? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/iron/web/color.rb', line 129

def opaque?
  @a == 255
end

#set(*args) ⇒ Object

All-purpose setter - pass in another Color, ‘#000000’, rgb vals… whatever



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# File 'lib/iron/web/color.rb', line 32

def set(*args)
  val = Color.parse(*args)
  unless val.nil?
    self.r = val.r
    self.g = val.g
    self.b = val.b
    self.a = val.a
  end
  self
end

#to_rgb(add_hash = true) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 121

def to_rgb(add_hash = true)
  (add_hash ? '#' : '') + to_hex(r) + to_hex(g) + to_hex(b)
end

#to_rgba(add_hash = true) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 125

def to_rgba(add_hash = true)
  to_rgb(add_hash) + to_hex(a)
end

#to_s(add_hash = true) ⇒ Object 



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# File 'lib/iron/web/color.rb', line 117

def to_s(add_hash = true)
  trans? ? to_rgba(add_hash) : to_rgb(add_hash)
end

#trans? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/iron/web/color.rb', line 133

def trans?
  @a != 255
end