Class: Color::YIQ

Inherits:
Object show all
Defined in:
lib/extensions/pdf-writer/color/yiq.rb,
lib/extensions/pdf-writer/color.rb

Overview

A colour object representing YIQ (NTSC) colour encoding.

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)



29
30
31
32
33
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 29

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



18
19
20
21
22
23
24
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 18

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 COLOR_TOLERANCE of each other.



42
43
44
45
46
47
48
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 42

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

#brightness ⇒ Object 



54
55
56
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 54

def brightness
  @y
end

#i ⇒ Object 



68
69
70
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 68

def i
  @i
end

#i=(ii) ⇒ Object 



71
72
73
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 71

def i=(ii)
  @i = Color.normalize(ii)
end

#inspect ⇒ Object 



81
82
83
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 81

def inspect
  "YIQ [%.2f%%, %.2f%%, %.2f%%]" % [ @y * 100, @i * 100, @q * 100 ]
end

#q ⇒ Object 



74
75
76
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 74

def q
  @q
end

#q=(qq) ⇒ Object 



77
78
79
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 77

def q=(qq)
  @q = Color.normalize(qq)
end

#to_grayscale ⇒ Object Also known as: to_greyscale 



57
58
59
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 57

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

#to_yiq ⇒ Object 



50
51
52
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 50

def to_yiq
  self
end

#y ⇒ Object 



62
63
64
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 62

def y
  @y
end

#y=(yy) ⇒ Object 



65
66
67
 
# File 'lib/extensions/pdf-writer/color/yiq.rb', line 65

def y=(yy)
  @y = Color.normalize(yy)
end