Module: TTFunk::Table::Cmap::Format06

Defined in:
lib/ttfunk/table/cmap/format06.rb

Overview

Format 6: Trimmed table mapping.

This module conditionally extends Subtable.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#code_map ⇒ Hash{Integer => Integer} (readonly)

Code map.

Returns:

  • (Hash{Integer => Integer})
Source Code
lib/ttfunk/table/cmap/format06.rb, line 16
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def code_map

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  @code_map

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end

#language ⇒ Integer (readonly)

Language.

Returns:

  • (Integer)
Source Code
lib/ttfunk/table/cmap/format06.rb, line 12
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def language

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  @language

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end

Class Method Details

.encode(charmap) ⇒ Hash

Encode the encoding record to format 6.

Parameters:

  • charmap (Hash{Integer => Integer}) —

    a hash mapping character codes to glyph IDs from the original font.

Returns:

  • (Hash) —
    • :charmap (Hash{Integer => Hash}) keys are the characrers in charset, values are hashes:
      • :old (Integer) - glyph ID in the original font.
      • :new (Integer) - glyph ID in the subset font. that maps the characters in charmap to a
    • :subtable (String) - serialized encoding record.
    • :max_glyph_id (Integer) - maximum glyph ID in the new font.
Source Code
lib/ttfunk/table/cmap/format06.rb, line 30
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def self.encode(charmap)

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  next_id = 0

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  glyph_map = { 0 => 0 }

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  sorted_chars = charmap.keys.sort

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  low_char = sorted_chars.first

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  high_char = sorted_chars.last

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  entry_count = 1 + high_char - low_char

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  glyph_indexes = Array.new(entry_count, 0)

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  new_map =

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    charmap.keys.sort.each_with_object({}) do |code, map|

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      glyph_map[charmap[code]] ||= next_id += 1

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      map[code] = { old: charmap[code], new: glyph_map[charmap[code]] }

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      glyph_indexes[code - low_char] = glyph_map[charmap[code]]

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    end

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  subtable = [

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    6, 10 + (entry_count * 2), 0, low_char, entry_count, *glyph_indexes,

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  ].pack('n*')

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  { charmap: new_map, subtable: subtable, max_glyph_id: next_id + 1 }

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end







    
  


  

    
Instance Method Details


    
      

  

  
    #[](code)  ⇒ Integer 
  

  

  


  

    
Get glyph ID for character code.



  





  

Parameters:


    
  
    
  • 
      
        code
      
      
        (Integer)
      
      
      
        —
        
    character code.
    

    
      
    
    • 
  




Returns:


    
  
    
  • 
      
      
        (Integer)
      
      
      
        —
        
    glyph ID.
    

    
      
    
    • 
  







  Source Code
  
lib/ttfunk/table/cmap/format06.rb, line 58

  
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def [](code)

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  @code_map[code] || 0

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end







    
      

  

  
    #supported?  ⇒ true 
  

  

  


  

    
Is this encoding record format supported?



  





  


Returns:


    
  
    
  • 
      
      
        (true)
      
      
      
    
    • 
  







  Source Code
  
lib/ttfunk/table/cmap/format06.rb, line 65

  
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def supported?

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  true

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end