Module: Color

Defined in:
lib/extensions/pdf-writer/color.rb,
lib/extensions/pdf-writer/color.rb,
lib/extensions/pdf-writer/color/grayscale.rb

Overview

Colour Management with Ruby

Defined Under Namespace

Modules: CSS, Palette Classes: CMYK, GrayScale, HSL, RGB, YIQ

Constant Summary collapse

COLOR_VERSION = 
'1.4.1'
COLOR_EPSILON =

The maximum “resolution” for colour math; if any value is less than or equal to this value, it is treated as zero.

1e-5
COLOR_TOLERANCE =

The tolerance for comparing the components of two colours. In general, colours are considered equal if all of their components are within this tolerance value of each other.

1e-4
GreyScale =

A synonym for Color::GrayScale.

GrayScale

Class Method Summary collapse

Class Method Details

.const_missing(name) ⇒ Object

:nodoc:



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# File 'lib/extensions/pdf-writer/color.rb', line 102

def self.const_missing(name) #:nodoc:
  case name
  when "VERSION", :VERSION, "COLOR_TOOLS_VERSION", :COLOR_TOOLS_VERSION
    warn "Color::#{name} has been deprecated. Use Color::COLOR_VERSION instead."
    Color::COLOR_VERSION
  else
    if Color::RGB.const_defined?(name)
      warn "Color::#{name} has been deprecated. Use Color::RGB::#{name} instead."
      Color::RGB.const_get(name)
    else
      super
    end
  end
end

.near_one?(value) ⇒ Boolean

Returns true if the value is within COLOR_EPSILON of one.

Returns:

  • (Boolean) 


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# File 'lib/extensions/pdf-writer/color.rb', line 46

def near_one?(value)
  near_zero?(value - 1.0)
end

.near_one_or_more?(value) ⇒ Boolean

Returns true if the value is within COLOR_EPSILON of one or more than one.

Returns:

  • (Boolean) 


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

def near_one_or_more?(value)
  (value > 1.0 or near_one?(value))
end

.near_zero?(value) ⇒ Boolean

Returns true if the value is less than COLOR_EPSILON.

Returns:

  • (Boolean) 


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# File 'lib/extensions/pdf-writer/color.rb', line 35

def near_zero?(value)
  (value.abs <= COLOR_EPSILON)
end

.near_zero_or_less?(value) ⇒ Boolean

Returns true if the value is within COLOR_EPSILON of zero or less than zero.

Returns:

  • (Boolean) 


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# File 'lib/extensions/pdf-writer/color.rb', line 41

def near_zero_or_less?(value)
  (value < 0.0 or near_zero?(value))
end

.new(values, mode = :rgb) ⇒ Object

Provides a thin veneer over the Color module to make it seem like this is Color 0.1.0 (a class) and not Color 1.4.1 (a module). This “constructor” will be removed in the future.

mode = :hsl

values must be an array of [ hue deg, sat %, lum % ]. A Color::HSL object will be created.

mode = :rgb

values will either be an HTML-style colour string or an array of [ red, green, blue ] (range 0 .. 255). A Color::RGB object will be created.

mode = :cmyk

values must be an array of [ cyan %, magenta %, yellow %, black % ]. A Color::CMYK object will be created.



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# File 'lib/extensions/pdf-writer/color.rb', line 128

def self.new(values, mode = :rgb)
  warn "Color.new has been deprecated. Use Color::#{mode.to_s.upcase}.new instead."
  color = case mode
          when :hsl
            Color::HSL.new(*values)
          when :rgb
            values = [ values ].flatten
            if values.size == 1
              Color::RGB.from_html(*values)
            else
              Color::RGB.new(*values)
            end
          when :cmyk
            Color::CMYK.new(*values)
          end
  color.to_hsl
end

.normalize(value) ⇒ Object Also known as: normalize_fractional

Normalizes the value to the range (0.0) .. (1.0).



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

def normalize(value)
  if near_zero_or_less? value
    0.0
  elsif near_one_or_more? value
    1.0
  else
    value
  end
end

.normalize_byte(value) ⇒ Object Also known as: normalize_8bit

Normalize the value to the range (0) .. (255).



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

def normalize_byte(value)
  normalize_to_range(value, 0..255).to_i
end

.normalize_to_range(value, range) ⇒ Object 



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

def normalize_to_range(value, range)
  range = (range.end..range.begin) if (range.end < range.begin)

  if value <= range.begin
    range.begin
  elsif value >= range.end
    range.end
  else
    value
  end
end

.normalize_word(value) ⇒ Object Also known as: normalize_16bit

Normalize the value to the range (0) .. (65535).



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# File 'lib/extensions/pdf-writer/color.rb', line 87

def normalize_word(value)
  normalize_to_range(value, 0..65535).to_i
end