Class: Color::YIQ

Inherits:
Object
  • Object
show all
Defined in:
lib/color/yiq.rb,
lib/color.rb

Overview

A colour object representing YIQ (NTSC) colour encoding.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(y = 0, i = 0, q = 0) ⇒ YIQ

Creates a YIQ colour object from percentages 0 .. 100.

Color::YIQ.new(10, 20, 30)



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# File 'lib/color/yiq.rb', line 28

def initialize(y = 0, i = 0, q = 0)
  @y = y / 100.0
  @i = i / 100.0
  @q = q / 100.0
end

Instance Attribute Details

#i ⇒ Object

Returns the value of attribute i.



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# File 'lib/color/yiq.rb', line 61

def i
  @i
end

#q ⇒ Object

Returns the value of attribute q.



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# File 'lib/color/yiq.rb', line 61

def q
  @q
end

#y ⇒ Object

Returns the value of attribute y.



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# File 'lib/color/yiq.rb', line 61

def y
  @y
end

Class Method Details

.from_fraction(y = 0, i = 0, q = 0) ⇒ Object

Creates a YIQ colour object from fractional values 0 .. 1.

Color::YIQ.new(0.3, 0.2, 0.1)



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# File 'lib/color/yiq.rb', line 17

def self.from_fraction(y = 0, i = 0, q = 0)
  color = Color::YIQ.new
  color.y = y
  color.i = i
  color.q = q
  color
end

Instance Method Details

#==(other) ⇒ Object

Compares the other colour to this one. The other colour will be converted to YIQ before comparison, so the comparison between a YIQ colour and a non-YIQ colour will be approximate and based on the other colour’s #to_yiq conversion. If there is no #to_yiq conversion, this will raise an exception. This will report that two YIQ values are equivalent if all component colours are within 1e-4 (0.0001) of each other.



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# File 'lib/color/yiq.rb', line 41

def ==(other)
  other = other.to_yiq
  other.kind_of?(Color::YIQ) and
  ((@y - other.y).abs <= 1e-4) and
  ((@i - other.i).abs <= 1e-4) and
  ((@q - other.q).abs <= 1e-4) 
end

#brightness ⇒ Object 



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# File 'lib/color/yiq.rb', line 53

def brightness
  @y
end

#to_grayscale ⇒ Object Also known as: to_greyscale 



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# File 'lib/color/yiq.rb', line 56

def to_grayscale
  Color::GrayScale.new(@y)
end

#to_yiq ⇒ Object 



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# File 'lib/color/yiq.rb', line 49

def to_yiq
  self
end