Class: Color::Palette::AdobeColor

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/extensions/pdf-writer/color/palette/adobecolor.rb

Overview

A class that can read an Adobe Color palette file (used for Photoshop swatches) and provide a Hash-like interface to the contents. Not all colour formats in ACO files are supported. Based largely off the information found by Larry Tesler.

Not all Adobe Color files have named colours; all named entries are returned as an array.

pal = Color::Palette::AdobeColor.from_file(my_aco_palette)
pal[0]          => Color::RGB<...>
pal["white"]    => [ Color::RGB<...> ]
pal["unknown"]  => [ Color::RGB<...>, Color::RGB<...>, ... ]

AdobeColor palettes are always indexable by insertion order (an integer key).

Version 2 palettes use UTF-16 colour names.

Constant Summary collapse

UwToSw =

Use this to convert the unsigned word to the signed word, if necessary.

proc { |n| (n >= (2 ** 16)) ? n - (2 ** 32) : n }

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#all?, #any?, #collect, #detect, #each_with_index, #find_all, #group_by, #inject, #max, #member?, #min, #sort, #sort_by, #to_a, #to_set

Constructor Details

#initialize(palette) ⇒ AdobeColor

Create a new AdobeColor palette from the palette file as a string.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 58

def initialize(palette)
  @colors     = []
  @names      = {}
  @statistics = Hash.new(0)
  @lost       = []
  @order      = []
  @version    = nil

  class << palette
    def readwords(count = 1)
      @offset ||= 0
      raise IndexError if @offset >= self.size
      val = self[@offset, count * 2]
      raise IndexError if val.nil? or val.size < (count * 2)
      val = val.unpack("n" * count)
      @offset += count * 2
      val
    end

    def readutf16(count = 1)
      @offset ||= 0
      raise IndexError if @offset >= self.size
      val = self[@offset, count * 2]
      raise IndexError if val.nil? or val.size < (count * 2)
      @offset += count * 2
      val
    end
  end

  @version, count = palette.readwords 2

  raise "Unknown AdobeColor palette version #@version." unless @version.between?(1, 2)

  count.times do
    space, w, x, y, z = palette.readwords 5
    name = nil
    if @version == 2
      raise IndexError unless palette.readwords == [ 0 ]
      len = palette.readwords
      name = palette.readutf16(len[0] - 1)
      raise IndexError unless palette.readwords == [ 0 ]
    end

    color = case space
            when 0 then # RGB
              @statistics[:rgb] += 1

              Color::RGB.new(w / 256, x / 256, y / 256)
            when 1 then # HS[BV] -- Convert to RGB
              @statistics[:hsb] += 1

              h = w / 65535.0
              s = x / 65535.0
              v = y / 65535.0

              if defined?(Color::HSB)
                Color::HSB.from_fraction(h, s, v)
              else
                @statistics[:converted] += 1
                if Color.near_zero_or_less?(s)
                  Color::RGB.from_fraction(v, v, v)
                else
                  if Color.near_one_or_more?(h)
                    vh = 0
                  else
                    vh = h * 6.0
                  end

                  vi = vh.floor
                  v1 = v.to_f * (1 - s.to_f)
                  v2 = v.to_f * (1 - s.to_f * (vh - vi))
                  v3 = v.to_f * (1 - s.to_f * (1 - (vh - vi)))

                  case vi
                  when 0 then Color::RGB.from_fraction(v, v3, v1)
                  when 1 then Color::RGB.from_fraction(v2, v, v1)
                  when 2 then Color::RGB.from_fraction(v1, v, v3)
                  when 3 then Color::RGB.from_fraction(v1, v2, v)
                  when 4 then Color::RGB.from_fraction(v3, v1, v)
                  else Color::RGB.from_fraction(v, v1, v2)
                  end
                end
              end
            when 2 then # CMYK
              @statistics[:cmyk] += 1
              Color::CMYK.from_percent(100 - (w / 655.35),
                                       100 - (x / 655.35),
                                       100 - (y / 655.35),
                                       100 - (z / 655.35))
            when 7 then # L*a*b*
              @statistics[:lab] += 1

              l = [w, 10000].min / 100.0
              a = [[-12800, UwToSw[x]].max, 12700].min / 100.0
              b = [[-12800, UwToSw[x]].max, 12700].min / 100.0

              if defined? Color::Lab
                Color::Lab.new(l, a, b)
              else
                [ space, w, x, y, z ]
              end
            when 8 then # Grayscale
              @statistics[:gray] += 1

              g = [w, 10000].min / 100.0
              Color::GrayScale.new(g)
            when 9 then # Wide CMYK
              @statistics[:wcmyk] += 1

              c = [w, 10000].min / 100.0
              m = [x, 10000].min / 100.0
              y = [y, 10000].min / 100.0
              k = [z, 10000].min / 100.0
              Color::CMYK.from_percent(c, m, y, k)
            else
              @statistics[space] += 1
              [ space, w, x, y, z ]
            end

    @order << [ color, name ]

    if color.kind_of? Array
      @lost << color
    else
      @colors << color

      if name
        @names[name] ||= []
        @names[name] << color
      end
    end
  end
end

Instance Attribute Details

#lost ⇒ Object (readonly)

Contains the “lost” colours in the palette. These colours could not be properly loaded (e.g., L*a*b* is not supported by Color, so it is “lost”) or are not understood by the algorithms.



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

def lost
  @lost
end

#statistics ⇒ Object (readonly)

Returns statistics about the nature of the colours loaded.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 48

def statistics
  @statistics
end

#version ⇒ Object (readonly)

Returns the value of attribute version.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 222

def version
  @version
end

Class Method Details

.from_file(filename) ⇒ Object

Create an AdobeColor palette object from the named file.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 37

def from_file(filename)
  File.open(filename, "rb") { |io| Color::Palette::AdobeColor.from_io(io) }
end

.from_io(io) ⇒ Object

Create an AdobeColor palette object from the provided IO.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 42

def from_io(io)
  Color::Palette::AdobeColor.new(io.read)
end

Instance Method Details

#[](key) ⇒ Object

If a Numeric key is provided, the single colour value at that position will be returned. If a String key is provided, the colour set (an array) for that colour name will be returned.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 200

def [](key)
  if key.kind_of?(Numeric)
    @colors[key]
  else
    @names[key]
  end
end

#each ⇒ Object

Loops through each colour.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 209

def each
  @colors.each { |el| yield el }
end

#each_name ⇒ Object

Loops through each named colour set.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 214

def each_name #:yields color_name, color_set:#
  @names.each { |color_name, color_set| yield color_name, color_set }
end

#size ⇒ Object 



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 218

def size
  @colors.size
end

#to_aco(version = @version) ⇒ Object

:nodoc:



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 224

def to_aco(version = @version) #:nodoc:
  res = ""

  res << [ version, @order.size ].pack("nn")

  @order.each do |cnpair|
    color, name = *cnpair

    # Note: HSB and CMYK formats are lost by the conversions performed on
    # import. They are turned into RGB and WCMYK, respectively.

    cstr = case color
           when Array
             color
           when Color::RGB
             r = [(color.red * 256).round, 65535].min
             g = [(color.green * 256).round, 65535].min
             b = [(color.blue * 256).round, 65535].min
             [ 0, r, g, b, 0 ]
           when Color::GrayScale
             g = [(color.gray * 100).round, 10000].min
             [ 8, g, 0, 0, 0 ]
           when Color::CMYK
             c = [(color.cyan * 100).round, 10000].min
             m = [(color.magenta * 100).round, 10000].min
             y = [(color.yellow * 100).round, 10000].min
             k = [(color.black * 100).round, 10000].min
             [ 9, c, m, y, k ]
           end
    cstr = cstr.pack("nnnnn")

    nstr = ""

    if version == 2
      if (name.size / 2 * 2) == name.size # only where s[0] == byte!
        nstr << [ 0, (name.size / 2) + 1 ].pack("nn")
        nstr << name
        nstr << [ 0 ].pack("n")
      else
        nstr << [ 0, 1, 0 ].pack("nnn")
      end
    end

    res << cstr << nstr
  end

  res
end

#values_at(*selectors) ⇒ Object

Provides the colour or colours at the provided selectors.



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# File 'lib/extensions/pdf-writer/color/palette/adobecolor.rb', line 193

def values_at(*selectors)
  @colors.values_at(*selectors)
end