module Color

Constants

COLOR_EPSILON: The maximum “resolution” for colour math; if any value is less than or equal to this value, it is treated as zero.
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.
COLOR_VERSION
GreyScale: A colour object representing shades of grey. Used primarily in PDF document creation.

Public Class Methods

near_one?(value) click to toggle source

Returns true if the value is within COLOR_EPSILON of one.

# File lib/color.rb, line 46
def near_one?(value)
  near_zero?(value - 1.0)
end

near_one_or_more?(value) click to toggle source

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

# File lib/color.rb, line 52
def near_one_or_more?(value)
  (value > 1.0 or near_one?(value))
end

near_zero?(value) click to toggle source

Returns true if the value is less than COLOR_EPSILON.

# File lib/color.rb, line 35
def near_zero?(value)
  (value.abs <= COLOR_EPSILON)
end

near_zero_or_less?(value) click to toggle source

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

# File lib/color.rb, line 41
def near_zero_or_less?(value)
  (value < 0.0 or near_zero?(value))
end

new(values, mode = :rgb) click to toggle source

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.

# File lib/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) click to toggle source

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

# File lib/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

Also aliased as: normalize_fractional

normalize_16bit(value)

Alias for: normalize_word

normalize_8bit(value)

Alias for: normalize_byte

normalize_byte(value) click to toggle source

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

# File lib/color.rb, line 81
def normalize_byte(value)
  normalize_to_range(value, 0..255).to_i
end

Also aliased as: normalize_8bit

normalize_fractional(value)

Alias for: normalize

normalize_to_range(value, range) click to toggle source

# File lib/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) click to toggle source

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

# File lib/color.rb, line 87
def normalize_word(value)
  normalize_to_range(value, 0..65535).to_i
end

Also aliased as: normalize_16bit