Class: HexaPDF::Font::Type1Wrapper

Inherits:
Object
  • Object
show all
Defined in:
lib/hexapdf/font/type1_wrapper.rb

Overview

This class wraps a generic Type1 font object and provides the methods needed for working with the font in a PDF context.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(document, font, pdf_object: nil, custom_encoding: false) ⇒ Type1Wrapper

Creates a new Type1Wrapper object wrapping the Type1 font.

The optional argument pdf_object can be used to set the PDF font object that this wrapper should be associated with. If no object is set, a suitable one is automatically created.

If pdf_object is provided, the PDF object’s encoding is used. Otherwise, the WinAnsiEncoding or, for ‘Special’ fonts, the font’s internal encoding is used. The optional argument custom_encoding can be set to true so that a custom encoding is used (only respected if pdf_object is not provided).



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# File 'lib/hexapdf/font/type1_wrapper.rb', line 119

def initialize(document, font, pdf_object: nil, custom_encoding: false)
  @wrapped_font = font
  @pdf_object = pdf_object || create_pdf_object(document)
  @missing_glyph_callable = document.config['font.on_missing_glyph']

  if pdf_object
    @encoding = pdf_object.encoding
    @max_code = 255 # Encoding is not modified
  elsif custom_encoding
    @encoding = Encoding::Base.new
    @encoding.code_to_name[32] = :space
    @max_code = 32 # 32 = space
  elsif @wrapped_font.metrics.character_set == 'Special'
    @encoding = @wrapped_font.encoding
    @max_code = 255 # Encoding is not modified
  else
    @encoding = Encoding.for_name(:WinAnsiEncoding)
    @max_code = 255 # Encoding is not modified
  end

  @zapf_dingbats_opt = {zapf_dingbats: (@wrapped_font.font_name == 'ZapfDingbats')}
  @name_to_glyph = {}
  @codepoint_to_glyph = {}
  @encoded_glyphs = {}
end

Instance Attribute Details

#pdf_object ⇒ Object (readonly)

Returns the PDF object associated with the wrapper.



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# File 'lib/hexapdf/font/type1_wrapper.rb', line 108

def pdf_object
  @pdf_object
end

#wrapped_font ⇒ Object (readonly)

Returns the wrapped Type1 font object.



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# File 'lib/hexapdf/font/type1_wrapper.rb', line 105

def wrapped_font
  @wrapped_font
end

Instance Method Details

#decode_utf8(str) ⇒ Object

Returns an array of glyph objects representing the characters in the UTF-8 encoded string.

If a Unicode codepoint is not available as glyph object, it is tried to map the codepoint using the font’s internal encoding. This is useful, for example, for the ZapfDingbats font to use ASCII characters for accessing the glyphs.



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# File 'lib/hexapdf/font/type1_wrapper.rb', line 173

def decode_utf8(str)
  str.codepoints.map! do |c|
    @codepoint_to_glyph[c] ||=
      begin
        name = Encoding::GlyphList.unicode_to_name(+'' << c, **@zapf_dingbats_opt)
        if @wrapped_font.metrics.character_set == 'Special' &&
            (name == :'.notdef' || !@wrapped_font.metrics.character_metrics.key?(name))
          name = @encoding.name(c)
        end
        name = +"u" << c.to_s(16).rjust(6, '0') if name == :'.notdef'
        glyph(name)
      end
  end
end

#encode(glyph) ⇒ Object

Encodes the glyph and returns the code string.



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# File 'lib/hexapdf/font/type1_wrapper.rb', line 189

def encode(glyph)
  @encoded_glyphs[glyph.name] ||=
    begin
      if glyph.name == @wrapped_font.missing_glyph_id
        raise HexaPDF::Error, "Glyph for #{glyph.str.inspect} missing"
      end
      code = @encoding.code(glyph.name)
      if code
        code.chr.freeze
      elsif @max_code < 255
        @max_code += 1
        @encoding.code_to_name[@max_code] = glyph.name
        @max_code.chr.freeze
      else
        raise HexaPDF::Error, "Type1 encoding has no codepoint for #{glyph.name}"
      end
    end
end

#font_type ⇒ Object

Returns the type of the font, i.e. :Type1.



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# File 'lib/hexapdf/font/type1_wrapper.rb', line 146

def font_type
  :Type1
end

#glyph(name) ⇒ Object

Returns a Glyph object for the given glyph name.



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# File 'lib/hexapdf/font/type1_wrapper.rb', line 156

def glyph(name)
  @name_to_glyph[name] ||=
    begin
      str = Encoding::GlyphList.name_to_unicode(name, **@zapf_dingbats_opt)
      if @wrapped_font.metrics.character_metrics.key?(name)
        Glyph.new(@wrapped_font, name, str)
      else
        @missing_glyph_callable.call(str, font_type, @wrapped_font)
      end
    end
end

#scaling_factor ⇒ Object

Returns 1 since all Type1 fonts use 1000 units for the em-square.



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# File 'lib/hexapdf/font/type1_wrapper.rb', line 151

def scaling_factor
  1
end