Class: Abachrome::Converters::LrgbToXyz

Inherits:
Base
  • Object
show all
Defined in:
lib/abachrome/converters/lrgb_to_xyz.rb

Instance Attribute Summary

Attributes inherited from Base

#from_space, #to_space

Class Method Summary collapse

Methods inherited from Base

#can_convert?, #convert, find_converter, #initialize, raise_unless, register

Constructor Details

This class inherits a constructor from Abachrome::Converters::Base

Class Method Details

.convert(lrgb_color) ⇒ Abachrome::Color

Converts a color from linear RGB color space to XYZ color space.

This method implements the linear RGB to XYZ transformation using the standard transformation matrix for the sRGB color space with D65 white point. The XYZ color space is the CIE 1931 color space that forms the basis for most other color space definitions and serves as a device-independent reference.

the same alpha as the input color

Raises:

  • (ArgumentError) —

    If the input color is not in linear RGB color space



15
16
17
18
19
20
21
22
23
24
25
26
 
# File 'lib/abachrome/converters/lrgb_to_xyz.rb', line 15

def self.convert(lrgb_color)
  raise_unless lrgb_color, :lrgb

  r, g, b = lrgb_color.coordinates.map { |_| AbcDecimal(_) }

  # Linear RGB to XYZ transformation matrix (sRGB/D65)
  x = (r * AD("0.4124564")) + (g * AD("0.3575761")) + (b * AD("0.1804375"))
  y = (r * AD("0.2126729")) + (g * AD("0.7151522")) + (b * AD("0.0721750"))
  z = (r * AD("0.0193339")) + (g * AD("0.1191920")) + (b * AD("0.9503041"))

  Color.new(ColorSpace.find(:xyz), [x, y, z], lrgb_color.alpha)
end