Class: Pdfrb::Document::Fonts

Inherits:
Object
  • Object
show all
Defined in:
lib/pdfrb/document/fonts.rb

Constant Summary collapse

STANDARDS = 
%w[
  Helvetica Helvetica-Bold Helvetica-Oblique Helvetica-BoldOblique
  Times-Roman Times-Bold Times-Italic Times-BoldItalic
  Courier Courier-Bold Courier-Oblique Courier-BoldOblique
  Symbol ZapfDingbats
].freeze
NO_ENCODING_FONTS = 
%w[Symbol ZapfDingbats].freeze
DEFAULT_WIDTH = 
500

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(document) ⇒ Fonts

Returns a new instance of Fonts.



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# File 'lib/pdfrb/document/fonts.rb', line 20

def initialize(document)
  @document = document
  @next_id = 1
  @registry = {}
  @encodings = {}
  @font_dicts = {}
  @afm_metrics = {}
  @used_codepoints = Hash.new { |h, k| h[k] = Set.new }
  @font_streams = {}
end

Instance Attribute Details

#document ⇒ Object (readonly)

Returns the value of attribute document.



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# File 'lib/pdfrb/document/fonts.rb', line 18

def document
  @document
end

Class Method Details

.build_tounicode(doc) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 190

def self.build_tounicode(doc)
  cmap_body = build_tounicode_cmap
  stream = doc.add({ Length: cmap_body.bytesize }, type: Pdfrb::Model::Cos::Stream)
  stream.stream = cmap_body
  stream
end

.build_tounicode_cmap ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 197

def self.build_tounicode_cmap
  lines = []
  lines << "/CIDInit /ProcSet findresource begin"
  lines << "12 dict begin"
  lines << "begincmap"
  lines << "/CIDSystemInfo << /Registry (Adobe) /Ordering (UCS) /Supplement 0 >> def"
  lines << "/CMapName /Adobe-Identity-UCS def"
  lines << "/CMapType 2 def"
  lines << "1 begincodespacerange"
  lines << "<00> <FF>"
  lines << "endcodespacerange"
  table = Pdfrb::Font::Encoding::WinAnsiEncoding::TABLE
  pairs = []
  table.each_with_index { |cp, byte| pairs << format("<%02X> <%04X>", byte, cp) if cp }
  pairs.each_slice(100) do |chunk|
    lines << "#{chunk.length} beginbfchar"
    lines.concat(chunk)
    lines << "endbfchar"
  end
  lines << "endcmap"
  lines << "CMapName currentdict /CMap defineresource pop"
  lines << "end"
  lines << "end"
  "#{lines.join("\n")}\n"
end

.loaders ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 164

def loaders; @loaders ||= []; end

.register_loader(loader) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 165

def register_loader(loader); loaders.unshift(loader); end

Instance Method Details

#[](name) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 54

def [](name); @registry[name]; end

#add(name_or_io) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 31

def add(name_or_io, **)
  name = font_name_for(name_or_io)
  cached = @registry[name]
  return cached if cached

  resource = next_resource_name
  font_dict = register_font(resource, name, **)
  @encodings[resource] = font_dict&.value&.[](:Encoding)
  @font_dicts[resource] = font_dict
  load_afm_metrics(resource, name)
  if @pending_io_data
    load_ttf_metrics(resource, @pending_io_data) unless @afm_metrics[resource]
    @font_streams[resource] = @pending_io_data
    @pending_io_data = nil
  end
  @pending_subtype = nil
  if @afm_metrics[resource] && font_dict&.value&.[](:Widths)
    font_dict.value[:Widths] = @afm_metrics[resource][:widths]
  end
  @registry[name] = resource
  resource
end

#each ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 56

def each(&)
  return enum_for(:each) unless block_given?

  @registry.each(&)
  self
end

#embedded?(resource) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/document/fonts.rb', line 137

def embedded?(resource)
  dict = @font_dicts[resource]
  return false unless dict

  desc = dict.value[:FontDescriptor]
  return false unless desc

  desc = document.object(desc) if desc.is_a?(Pdfrb::Model::Reference)
  desc&.value&.key?(:FontFile2)
end

#encodable?(text, resource) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/document/fonts.rb', line 83

def encodable?(text, resource); !encode_text(text, resource).include?("?"); end

#encode_text(text, resource) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 75

def encode_text(text, resource)
  text.to_s.each_codepoint { |cp| @used_codepoints[resource] << cp }
  enc = @encodings[resource]
  return text.to_s.b unless enc

  Pdfrb::Font::Encoding.encode(enc, text.to_s)
end

#encoding_for(resource) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 73

def encoding_for(resource); @encodings[resource]; end

#glyph_width(resource, codepoint) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 113

def glyph_width(resource, codepoint)
  metrics = @afm_metrics[resource]
  return DEFAULT_WIDTH unless metrics

  cp = codepoint.is_a?(String) ? (codepoint.each_codepoint.first || 0) : codepoint.to_i
  return 0 if cp > 255

  metrics[:widths][cp] || 0
end

#glyph_widths(resource, codepoints) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 123

def glyph_widths(resource, codepoints)
  cps = codepoints.is_a?(String) ? codepoints.each_codepoint.to_a : codepoints
  cps.map { |cp| glyph_width(resource, cp) }
end

#measure_text(text, font:, size:) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 85

def measure_text(text, font:, size:)
  return 0 unless text && size

  metrics = @afm_metrics[font]
  return text.to_s.length * size.to_f * 0.5 unless metrics

  total = text.to_s.each_char.sum do |ch|
    byte = ch.bytes.first || 0
    metrics[:widths][byte] || DEFAULT_WIDTH
  end
  total * size.to_f / 1000.0
end

#metrics_for(resource) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 128

def metrics_for(resource); @afm_metrics[resource]; end

#register_usage(font_dict, text) ⇒ Object

Record that text was drawn with font_dict so the write-time subsetter knows which codepoints each embedded font must retain.



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# File 'lib/pdfrb/document/fonts.rb', line 68

def register_usage(font_dict, text)
  resource = @font_dicts.key(font_dict)
  track(resource, text) if resource
end

#subset_fonts! ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 148

def subset_fonts!
  @font_streams.each do |resource, data|
    next unless valid_font_data?(data)

    codepoints = @used_codepoints[resource]
    next if codepoints.empty?

    begin
      subset_font(resource, data, codepoints)
    rescue StandardError
      next
    end
  end
end

#text_width(text, _resource, size:) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 98

def text_width(text, _resource, size:)
  return 0 unless text && size

  res = @afm_metrics[_resource] ? _resource : (@registry[_resource.to_s] || _resource)
  metrics = @afm_metrics[res]
  return text.to_s.length * size.to_f * 0.5 unless metrics

  upem = metrics[:units_per_em] || 1000
  total = text.to_s.each_char.sum do |ch|
    byte = ch.bytes.first || 0
    metrics[:widths][byte] || DEFAULT_WIDTH
  end
  total * size.to_f / upem.to_f
end

#used_codepoints(resource) ⇒ Object 



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# File 'lib/pdfrb/document/fonts.rb', line 63

def used_codepoints(resource); @used_codepoints[resource]; end

#valid_font_data?(data) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/document/fonts.rb', line 130

def valid_font_data?(data)
  return false unless data.is_a?(String) && data.bytesize >= 4

  magic = data.byteslice(0, 4)
  ["ttcf".b, "\x00\x01\x00\x00".b, "OTTO".b, "true".b, "typ1".b].include?(magic)
end