Class: Spectrum::Palette::AdobeColor

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/spectrum/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 = Spectrum::Palette::AdobeColor.from_file(my_aco_palette)
pal[0]          => Spectrum::RGB<...>
pal["white"]    => [ Spectrum::RGB<...> ]
pal["unknown"]  => [ Spectrum::RGB<...>, Spectrum::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

Constructor Details

#initialize(palette) ⇒ AdobeColor

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



58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
 
# File 'lib/spectrum/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

              Spectrum::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?(Spectrum::HSB)
                Spectrum::HSB.from_fraction(h, s, v)
              else
                @statistics[:converted] += 1
                if Spectrum.near_zero_or_less?(s)
                  Spectrum::RGB.from_fraction(v, v, v)
                else
                  if Spectrum.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 Spectrum::RGB.from_fraction(v, v3, v1)
                  when 1 then Spectrum::RGB.from_fraction(v2, v, v1)
                  when 2 then Spectrum::RGB.from_fraction(v1, v, v3)
                  when 3 then Spectrum::RGB.from_fraction(v1, v2, v)
                  when 4 then Spectrum::RGB.from_fraction(v3, v1, v)
                  else Spectrum::RGB.from_fraction(v, v1, v2)
                  end
                end
              end
            when 2 then # CMYK
              @statistics[:cmyk] += 1
              Spectrum::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? Spectrum::Lab
                Spectrum::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
              Spectrum::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
              Spectrum::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.



52
53
54
 
# File 'lib/spectrum/palette/adobecolor.rb', line 52

def lost
  @lost
end

#statistics ⇒ Object (readonly)

Returns statistics about the nature of the colours loaded.



48
49
50
 
# File 'lib/spectrum/palette/adobecolor.rb', line 48

def statistics
  @statistics
end

#version ⇒ Object (readonly)

Returns the value of attribute version.



222
223
224
 
# File 'lib/spectrum/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.



37
38
39
 
# File 'lib/spectrum/palette/adobecolor.rb', line 37

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

.from_io(io) ⇒ Object

Create an AdobeColor palette object from the provided IO.



42
43
44
 
# File 'lib/spectrum/palette/adobecolor.rb', line 42

def from_io(io)
  Spectrum::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.



200
201
202
203
204
205
206
 
# File 'lib/spectrum/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.



209
210
211
 
# File 'lib/spectrum/palette/adobecolor.rb', line 209

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

#each_name ⇒ Object

Loops through each named colour set.



214
215
216
 
# File 'lib/spectrum/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 



218
219
220
 
# File 'lib/spectrum/palette/adobecolor.rb', line 218

def size
  @colors.size
end

#to_aco(version = @version) ⇒ Object

:nodoc:



224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
 
# File 'lib/spectrum/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 Spectrum::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 Spectrum::GrayScale
             g = [(color.gray * 100).round, 10000].min
             [ 8, g, 0, 0, 0 ]
           when Spectrum::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.



193
194
195
 
# File 'lib/spectrum/palette/adobecolor.rb', line 193

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