Class: TTFunk::Subset::Unicode8Bit

Inherits:
Base
  • Object
show all
Defined in:
lib/ttfunk/subset/unicode_8bit.rb

Overview

An 8-bit Unicode-based subset. It can include any Unicode character but limits number of characters so that the could be encoded by a single byte.

Constant Summary

Constants inherited from Base

Base::MICROSOFT_PLATFORM_ID, Base::MS_SYMBOL_ENCODING_ID

Instance Attribute Summary

Attributes inherited from Base

#original

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_cmap

Constructor Details

#initialize(original) ⇒ Unicode8Bit

Returns a new instance of Unicode8Bit.

Parameters:

Source Code
lib/ttfunk/subset/unicode_8bit.rb, line 12
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def initialize(original)

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  super

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  @subset = { 0x20 => 0x20 }

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  @unicodes = { 0x20 => 0x20 }

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  @next = 0x21 # apparently, PDF's don't like to use chars between 0-31

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end

Instance Method Details

#covers?(character) ⇒ Boolean

Can this subset include the character?

Parameters:

  • character (Integer) —

    Unicode codepoint

Returns:

  • (Boolean)
Source Code
lib/ttfunk/subset/unicode_8bit.rb, line 49
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def covers?(character)

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  @unicodes.key?(character) || @next < 256

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end

#from_unicode(character) ⇒ Integer

Get character code for Unicode codepoint.

Parameters:

  • character (Integer) —

    Unicode codepoint

Returns:

  • (Integer)
Source Code
lib/ttfunk/subset/unicode_8bit.rb, line 65
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def from_unicode(character)

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  @unicodes[character]

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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/unicode_8bit.rb, line 57
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def includes?(character)

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  @unicodes.key?(character)

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end

#new_cmap_table ⇒ TTFunk::Table::Cmap

Get cmap table for this subset.

Returns:

Source Code
lib/ttfunk/subset/unicode_8bit.rb, line 72
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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_object({}) do |(code, unicode), map|

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          map[code] = unicode_cmap[unicode]

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          map

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        end

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      # since we're mapping a subset of the unicode glyphs into an

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      # arbitrary 256-character space, the actual encoding we're

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      # using is irrelevant. We choose MacRoman because it's a 256-character

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      # encoding that happens to be well-supported in both TTF and

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      # PDF formats.

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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/unicode_8bit.rb, line 94

  
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def original_glyph_ids

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  ([0] + @unicodes.keys.map { |unicode| unicode_cmap[unicode] }).uniq.sort

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end







    
      

  

  
    #to_unicode_map  ⇒ Hash{Integer => Integer} 
  

  

  


  

    
Get a mapping from this subset to Unicode.



  





  


Returns:


    
  
    
  • 
      
      
        (Hash{Integer => Integer})
      
      
      
    
    • 
  







  Source Code
  
lib/ttfunk/subset/unicode_8bit.rb, line 29

  
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def to_unicode_map

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  @subset.dup

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end







    
      

  

  
    #unicode?  ⇒ true 
  

  

  


  

    
Is this a Unicode-based subset?



  





  


Returns:


    
  
    
  • 
      
      
        (true)
      
      
      
    
    • 
  







  Source Code
  
lib/ttfunk/subset/unicode_8bit.rb, line 22

  
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def unicode?

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  true

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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/unicode_8bit.rb, line 37

  
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def use(character)

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  unless @unicodes.key?(character)

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    @subset[@next] = character

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    @unicodes[character] = @next

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    @next += 1

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  end

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end