subtable.rb in ttfunk-1.8.0

- old
+ new

@@ -3,25 +3,58 @@
 require_relative '../../reader'
 
 module TTFunk
   class Table
     class Cmap
+      # Character to Glyph Index encoding record.
+      # This class can be extended with a format-specific
+      #
+      # @see TTFunk::Table::Cmap::Format00
+      # @see TTFunk::Table::Cmap::Format04
+      # @see TTFunk::Table::Cmap::Format06
+      # @see TTFunk::Table::Cmap::Format10
+      # @see TTFunk::Table::Cmap::Format12
       class Subtable
         include Reader
 
+        # Platform ID.
+        # @return [Integer]
         attr_reader :platform_id
+
+        # Platform-specific encoding ID.
+        # @return [Integere]
         attr_reader :encoding_id
+
+        # Record encoding format.
+        # @return [Integer]
         attr_reader :format
 
+        # Most used encoding mappings.
         ENCODING_MAPPINGS = {
           mac_roman: { platform_id: 1, encoding_id: 0 }.freeze,
           # Use microsoft unicode, instead of generic unicode, for optimal
           # Windows support
           unicode: { platform_id: 3, encoding_id: 1 }.freeze,
-          unicode_ucs4: { platform_id: 3, encoding_id: 10 }.freeze
+          unicode_ucs4: { platform_id: 3, encoding_id: 10 }.freeze,
         }.freeze
 
+        # Encode encoding record.
+        #
+        # @param charmap [Hash{Integer => Integer}] keys are code points in the
+        #   used encoding, values are Unicode code points.
+        # @param encoding [Symbol] - one of the encodign mapping in
+        #   {ENCODING_MAPPINGS}
+        # @return [Hash]
+        #   * `:platform_id` (<tt>Integer</tt>) - Platform ID of this encoding record.
+        #   * `:encoding_id` (<tt>Integer</tt>) - Encodign ID of this encoding record.
+        #   * `:subtable` (<tt>String</tt>) - encoded encoding record.
+        #   * `:max_glyph_id` (<tt>Integer</tt>) - maximum glyph ID in this encoding
+        #     record.
+        #   * `:charmap` (<tt>Hash{Integer => Hash}</tt>) - keys are codepoints in this
+        #     encoding record, values are hashes:
+        #     * `:new` - new glyph ID.
+        #     * `:old` - glyph ID in the original font.
         def self.encode(charmap, encoding)
           case encoding
           when :mac_roman
             result = Format00.encode(charmap)
           when :unicode
@@ -41,15 +74,17 @@
             encoding_id: mapping[:encoding_id],
             subtable: [
               mapping[:platform_id],
               mapping[:encoding_id],
               12,
-              result[:subtable]
-            ].pack('nnNA*')
+              result[:subtable],
+            ].pack('nnNA*'),
           )
         end
 
+        # @param file [TTFunk::File]
+        # @param table_start [Integer]
         def initialize(file, table_start)
           @file = file
           @platform_id, @encoding_id, @offset = read(8, 'nnN')
           @offset += table_start
 
@@ -66,19 +101,28 @@
 
             parse_cmap!
           end
         end
 
+        # Is this an encoding record for Unicode?
+        #
+        # @return [Boolean]
         def unicode?
-          platform_id == 3 && (encoding_id == 1 || encoding_id == 10) &&
-            format != 0 ||
-            platform_id.zero? && format != 0
+          (platform_id == 3 && (encoding_id == 1 || encoding_id == 10) && format != 0) ||
+            (platform_id.zero? && format != 0)
         end
 
+        # Is this encoding record format supported?
+        #
+        # @return [Boolean]
         def supported?
           false
         end
 
+        # Get glyph ID for character code.
+        #
+        # @param _code [Integer] character code.
+        # @return [Integer] glyph ID.
         def [](_code)
           raise NotImplementedError, "cmap format #{@format} is not supported"
         end
 
         private