resolves asciidoctor#155 support CMYK color values

- parse CMYK color values in theme
- parse CMYK color values in formatted text
- avoid redundant processing of color values when loading theme
- mixin color types into color values
- show example of CMYK value in default theme
- code formatting

data/themes/default-theme.yml

@@ -28,7 +28,13 @@ page:
   # size can be a named size (e.g., A4) or custom dimensions (e.g., [8.25in, 11.69in])
   size: Letter
 base:
+  # color as hex string (leading # is optional)
   font_color: 333333
+  # color as RGB array
+  #font_color: [51, 51, 51]
+  # color as CMYK array (approximated)
+  #font_color: [0, 0, 0, 0.92]
+  #font_color: [0, 0, 0, 92%]
   font_family: NotoSerif
   # choose one of these font_size/line_height_length combinations
   #font_size: 14

lib/asciidoctor-pdf/converter.rb

@@ -1185,6 +1185,7 @@ def convert_inline_button node
 
   def convert_inline_callout node
     if (conum_color = @theme.conum_font_color)
+      # NOTE CMYK value gets flattened here, but is restored by formatted text parser
       %(<color rgb="#{conum_color}">#{conum_glyph node.text.to_i}</color>)
     else
       node.text
@@ -1196,6 +1197,7 @@ def convert_inline_footnote node
       #text = node.document.footnotes.find {|fn| fn.index == index }.text
       %( [#{node.text}])
     elsif node.type == :xref
+      # NOTE footnote reference not found
       %( <color rgb="FF0000">[#{node.text}]</color>)
     end
   end
@@ -1437,6 +1439,7 @@ def layout_prose string, opts = {}
     if (anchor = opts.delete :anchor)
       # FIXME won't work if inline_format is true; should instead pass through as attribute w/ link color set
       if (link_color = opts.delete :link_color)
+        # NOTE CMYK value gets flattened here, but is restored by formatted text parser
         string = %(<a anchor="#{anchor}"><color rgb="#{link_color}">#{string}</color></a>)
       else
         string = %(<a anchor="#{anchor}">#{string}</a>)
@@ -1522,6 +1525,7 @@ def layout_toc_level sections, num_levels, line_metrics, dot_width, num_front_ma
       # NOTE we do some cursor hacking here so the dots don't affect vertical alignment
       start_page_number = page_number
       start_cursor = cursor
+      # NOTE CMYK value gets flattened here, but is restored by formatted text parser
       typeset_text %(<a anchor="#{sect_anchor = (sect.attr 'anchor') || sect.id}"><color rgb="#{toc_font_color}">#{sect_title}</color></a>), line_metrics, inline_format: true
       # we only write the label if this is a dry run
       unless scratch?

lib/asciidoctor-pdf/prawn_ext/extensions.rb

@@ -347,8 +347,8 @@ def fill_absolute_bounds f_color = fill_color
   # color, stroke color and line width on the document are restored.
   #
   def fill_and_stroke_bounds f_color = fill_color, s_color = stroke_color, options = {}
-    no_fill = (f_color.nil? || f_color.to_s == 'transparent')
-    no_stroke = (s_color.nil? || s_color.to_s == 'transparent')
+    no_fill = !f_color || f_color == 'transparent'
+    no_stroke = !s_color || s_color == 'transparent'
     return if no_fill && no_stroke
     save_graphics_state do
       radius = options[:radius] || 0

lib/asciidoctor-pdf/prawn_ext/formatted_text/transform.rb

@@ -51,6 +51,7 @@ def apply(parsed)
           previous_fragment_is_text = false
         end
       when :text, :entity
+        # TODO could avoid this redundant type check by splitting :text and :entity cases
         node_text = if node_type == :text
           node[:value]
         elsif node_type == :entity
@@ -111,12 +112,25 @@ def build_fragment(fragment, tag_name = nil, attrs = {})
     when :color
       if !fragment[:color]
         if (rgb = attrs[:rgb])
-          if rgb[0] == '#'
-            rgb = rgb[1..-1]
+          case rgb.chr
+          when '#'
+            fragment[:color] = rgb[1..-1]
+          when '['
+            # treat value as CMYK array (e.g., "[50, 100, 0, 0]")
+            fragment[:color] = rgb[1..-1].chomp(']').split(', ').map(&:to_i)
+            # ...or we could honor an rgb array too
+            #case (vals = rgb[1..-1].chomp(']').split(', ')).size
+            #when 4
+            #  fragment[:color] = vals.map(&:to_i)
+            #when 3
+            #  fragment[:color] = vals.map {|e| '%02X' % e.to_i }.join
+            #end
+          else
+            fragment[:color] = rgb
           end
-          fragment[:color] = rgb
+        # QUESTION should we even support r,g,b and c,m,y,k as individual values?
         elsif (r = attrs[:r]) && (g = attrs[:g]) && (b = attrs[:b])
-          fragment[:color] = [r, g, b].map {|e| '%02x' % e.to_i }.join
+          fragment[:color] = [r, g, b].map {|e| '%02X' % e.to_i }.join
         elsif (c = attrs[:c]) && (m = attrs[:m]) && (y = attrs[:y]) && (k = attrs[:k])
           fragment[:color] = [c.to_i, m.to_i, y.to_i, k.to_i]
         end

lib/asciidoctor-pdf/theme_loader.rb

@@ -5,30 +5,45 @@
 module Asciidoctor
 module Pdf
 class ThemeLoader
-  DataDir = ::File.expand_path ::File.join(::File.dirname(__FILE__), '..', '..', 'data')
-  ThemesDir = ::File.join DataDir, 'themes'
-  FontsDir = ::File.join DataDir, 'fonts'
+  DataDir = ::File.expand_path(::File.join(::File.dirname(__FILE__), '..', '..', 'data'))
+  ThemesDir = ::File.join(DataDir, 'themes')
+  FontsDir = ::File.join(DataDir, 'fonts')
   HexColorValueRx = /_color: (?<quote>"|'|)#?(?<value>[A-Za-z0-9]{3,6})\k<quote>$/
 
+  module ColorValue; end
+
+  class HexColorValue < String
+    include ColorValue
+  end
+
+  # A marker module for a normalized CMYK array
+  # Prevents normalizing CMYK value more than once
+  module CmykColorValue
+    include ColorValue
+    def to_s
+      %([#{join ', '}])
+    end
+  end
+
   def self.resolve_theme_file theme_name = nil, theme_path = nil
     theme_name ||= 'default'
     # if .yml extension is given, assume it's a full file name
-    if theme_name.end_with? '.yml'
+    if theme_name.end_with?('.yml')
       # FIXME restrict to jail!
       # QUESTION why are we not using expand_path in this case?
-      theme_path ? (::File.join theme_path, theme_name) : theme_name
+      theme_path ? ::File.join(theme_path, theme_name) : theme_name
     else
       # QUESTION should we append '-theme.yml' or just '.yml'?
-      ::File.expand_path %(#{theme_name}-theme.yml), (theme_path || ThemesDir)
+      ::File.expand_path(%(#{theme_name}-theme.yml), (theme_path || ThemesDir))
     end
   end
 
   def self.resolve_theme_asset asset_path, theme_path = nil
-    ::File.expand_path asset_path, (theme_path || ThemesDir)
+    ::File.expand_path(asset_path, (theme_path || ThemesDir))
   end
 
   def self.load_theme theme_name = nil, theme_path = nil
-    load_file (resolve_theme_file theme_name, theme_path)
+    load_file(resolve_theme_file(theme_name, theme_path))
   end
 
   def self.load_file filename
@@ -37,15 +52,15 @@ def self.load_file filename
   end
 
   def load hash
-    hash.inject(::OpenStruct.new) do |s, (k, v)|
-      if v.kind_of? ::Hash
-        v.each do |k2, v2|
-          s[%(#{k}_#{k2})] = (k2.end_with? '_color') ? to_hex(evaluate(v2, s)) : evaluate(v2, s)
+    hash.inject(::OpenStruct.new) do |data, (key, val)|
+      if ::Hash === val
+        val.each do |key2, val2|
+          data[%(#{key}_#{key2})] = key2.end_with?('_color') ? to_color(evaluate(val2, data)) : evaluate(val2, data)
         end
       else
-        s[k] = (k.end_with? '_color') ? to_hex(evaluate(v, s)) : evaluate(v, s)
+        data[key] = key.end_with?('_color') ? to_color(evaluate(val, data)) : evaluate(val, data)
       end
-      s
+      data
     end
   end
 
@@ -62,20 +77,18 @@ def evaluate expr, vars
     end
   end
 
+  # NOTE assume expr is a String
   def expand_vars expr, vars
-    if expr.include? '$'
-      if (expr.start_with? '$') && (expr.match /^\$([a-z0-9_]+)$/)
-        vars[$1]
-      else
-        expr.gsub(/\$([a-z0-9_]+)/) { vars[$1] }
-      end
+    return expr unless expr.include? '$'
+    if expr.start_with?('$') && expr.match(/^\$([a-z0-9_]+)$/)
+      vars[$1]
     else
-      expr
+      expr.gsub(/\$([a-z0-9_]+)/) { vars[$1] }
     end
   end
 
   def evaluate_math expr
-    return expr unless ::String === expr
+    return expr if !(::String === expr) || ColorValue === expr
     original = expr
     # FIXME quick HACK to turn a single negative number into an expression
     expr = %(1 - #{expr[1..-1]}) if expr.start_with?('-')
@@ -108,35 +121,70 @@ def evaluate_math expr
       expr = result
       break if unchanged
     end
-    if (expr.end_with? ')') && (expr.match /^(round|floor|ceil)\(/)
+    if expr.end_with?(')') && expr.match(/^(round|floor|ceil)\(/)
       op = $1
       offset = op.length + 1
       expr = expr[offset...-1].to_f.send(op.to_sym)
     end
-    if original == expr
-      expr
+    if expr == original
+      original
     else
-      if ((int_val = expr.to_i) == (float_val = expr.to_f))
-        int_val
-      else
-        float_val
-      end
+      (int_val = expr.to_i) == (flt_val = expr.to_f) ? int_val : flt_val
     end
   end
 
-  def to_hex value
-    str = value.to_s
-    return str if str == 'transparent'
-    hex = case str.size
+  def to_color value
+    case value
+    when ColorValue
+      # already converted
+      return value
+    when ::String
+      if value == 'transparent'
+        # FIXME should we have a TransparentColorValue class?
+        return HexColorValue.new(value)
+      elsif value.size == 6
+        return HexColorValue.new(value.upcase)
+      end
+    when ::Array
+      case value.size
+      # CMYK value
+      when 4
+        value = value.map {|e|
+          if ::Numeric === e
+            e = e * 100.0 unless e > 1
+          else
+            e = e.to_s.chomp('%').to_f
+          end
+          (e == (int_e = e.to_i)) ? int_e : e
+        }
+        if value == [0, 0, 0, 0]
+          return HexColorValue.new('FFFFFF')
+        else
+          value.extend CmykColorValue
+          return value
+        end
+      # RGB value
+      when 3
+        return HexColorValue.new(value.map {|e| '%02X' % e}.join)
+      # Nonsense array value; flatten to string
+      else
+        value = value.join
+      end
+    else
+      # Unknown type; coerce to a string
+      value = %(#{value})
+    end
+    value = case value.size
     when 6
-      str
+      value
     when 3
-      str.each_char.map {|it| it * 2 }.join 
+      # expand hex shorthand (e.g., f00 -> ff0000)
+      value.each_char.map {|c| c * 2 }.join
     else
-      # CAUTION: YAML will misinterpret values with leading zeros (e.g., 000011) that are not quoted (aside from 000000)
-      str[0..5].rjust(6, '0')
+      # truncate or pad with leading zeros (e.g., ff -> 0000ff)
+      value[0..5].rjust 6, '0'
     end
-    hex.upcase
+    HexColorValue.new(value.upcase)
   end
 end
 end