Class: TTFunk::Subset::CodePage

Inherits:
Base
  • Object
show all
Defined in:
lib/ttfunk/subset/code_page.rb

Overview

A subset that uses standard code page encoding.

Direct Known Subclasses

MacRoman, Windows1252

Constant Summary

Constants inherited from Base

Base::MICROSOFT_PLATFORM_ID, Base::MS_SYMBOL_ENCODING_ID

Instance Attribute Summary collapse

Attributes inherited from Base

#original

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Base

#collect_glyphs, #encode, #encoder_klass, #glyphs, #microsoft_symbol?, #new_to_old_glyph, #old_to_new_glyph, #unicode?, #unicode_cmap

Constructor Details

#initialize(original, code_page, encoding) ⇒ CodePage

Returns a new instance of CodePage.

Parameters:

  • original (TTFunk::File)
  • code_page (Integer)
  • encoding (Encoding, String, Symbol)
Source Code
lib/ttfunk/subset/code_page.rb, line 47
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def initialize(original, code_page, encoding)

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  super(original)

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  @code_page = code_page

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  @encoding = encoding

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  @subset = Array.new(256)

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  @from_unicode_cache = {}

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  use(space_char_code)

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end

Instance Attribute Details

#code_page ⇒ Integer (readonly)

Code page used in this subset. This is used for proper OS/2 table encoding.

Returns:

  • (Integer)
Source Code
lib/ttfunk/subset/code_page.rb, line 38
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def code_page

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  @code_page

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end

#encoding ⇒ Encoding, ... (readonly)

Encoding used in this subset.

Returns:

  • (Encoding, String, Symbol)
Source Code
lib/ttfunk/subset/code_page.rb, line 42
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def encoding

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  @encoding

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end

Class Method Details

.unicode_mapping_for(encoding) ⇒ Hash{Integer => Integer}

Get a mapping from an encoding to Unicode

Parameters:

  • encoding (Encoding, String, Symbol)

Returns:

  • (Hash{Integer => Integer})
Source Code
lib/ttfunk/subset/code_page.rb, line 16
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def unicode_mapping_for(encoding)

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  mapping_cache[encoding] ||=

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    (0..255).each_with_object({}) do |c, ret|

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      codepoint =

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        c.chr(encoding)

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          .encode(Encoding::UTF_8, undef: :replace, replace: '')

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          .codepoints

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          .first

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      ret[c] = codepoint if codepoint

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    end

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end

Instance Method Details

#covers?(character) ⇒ Boolean

Can this subset include the character? This depends on the encoding used in this subset.

Parameters:

  • character (Integer) —

    Unicode codepoint

Returns:

  • (Boolean)
Source Code
lib/ttfunk/subset/code_page.rb, line 77
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def covers?(character)

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  !from_unicode(character).nil?

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end

#from_unicode(character) ⇒ Integer?

Get character code for Unicode codepoint.

Parameters:

  • character (Integer) —

    Unicode codepoint

Returns:

  • (Integer, nil)
Source Code
lib/ttfunk/subset/code_page.rb, line 94
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def from_unicode(character)

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  @from_unicode_cache[character] ||= (+'' << character).encode!(encoding).ord

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rescue Encoding::UndefinedConversionError

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  nil

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end

#includes?(character) ⇒ Boolean

Does this subset actually has the character?

Parameters:

  • character (Integer) —

    Unicode codepoint

Returns:

  • (Boolean)
Source Code
lib/ttfunk/subset/code_page.rb, line 85
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def includes?(character)

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  code = from_unicode(character)

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  code && @subset[code]

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end

#new_cmap_table ⇒ TTFunk::Table::Cmap

Get cmap table for this subset.

Returns:

Source Code
lib/ttfunk/subset/code_page.rb, line 103
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def new_cmap_table

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  @new_cmap_table ||=

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    begin

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      mapping = {}

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      @subset.each_with_index do |unicode, roman|

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        mapping[roman] = unicode_cmap[unicode]

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      end

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      TTFunk::Table::Cmap.encode(mapping, :mac_roman)

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    end

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end







    
      

  

  
    #original_glyph_ids  ⇒ Array<Integer> 
  

  

  


  

    
Get the list of Glyph IDs from the original font that are in this
subset.



  





  


Returns:


    
  
    
  • 
      
      
        (Array<Integer>)
      
      
      
    
    • 
  







  Source Code
  
lib/ttfunk/subset/code_page.rb, line 120

  
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def original_glyph_ids

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  ([0] + @subset.map { |unicode| unicode && unicode_cmap[unicode] })

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    .compact.uniq.sort

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end







    
      

  

  
    #space_char_code  ⇒ Integer? 
  

  

  


  

    
Get a chacter code for Space in this subset



  





  


Returns:


    
  
    
  • 
      
      
        (Integer, nil)
      
      
      
    
    • 
  







  Source Code
  
lib/ttfunk/subset/code_page.rb, line 128

  
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def space_char_code

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  @space_char_code ||= from_unicode(Unicode::SPACE_CHAR)

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end







    
      

  

  
    #to_unicode_map  ⇒ Hash 
  

  

  


  

    
Get a mapping from this subset to Unicode.



  





  


Returns:


    
  
    
  • 
      
      
        (Hash)
      
      
      
    
    • 
  







  Source Code
  
lib/ttfunk/subset/code_page.rb, line 59

  
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def to_unicode_map

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  self.class.unicode_mapping_for(encoding)

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    .select { |codepoint, _unicode| @subset[codepoint] }

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end







    
      

  

  
    #use(character)  ⇒ void 
  

  

  


  

    
This method returns an undefined value.
Add a character to subset.



  





  

Parameters:


    
  
    
  • 
      
        character
      
      
        (Integer)
      
      
      
        —
        
    Unicode codepoint
    

    
      
    
    • 
  








  Source Code
  
lib/ttfunk/subset/code_page.rb, line 68

  
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def use(character)

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  @subset[from_unicode(character)] = character

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end