Class: Prawn::Font::AFM

Inherits:

Prawn::Font

• Object
• Prawn::Font
• Prawn::Font::AFM

show all

Defined in:

lib/prawn/font/afm.rb

Constant Summary

BUILT_INS =

%w[ Courier Helvetica Times-Roman Symbol ZapfDingbats
Courier-Bold Courier-Oblique Courier-BoldOblique
Times-Bold Times-Italic Times-BoldItalic
Helvetica-Bold Helvetica-Oblique Helvetica-BoldOblique ]

Instance Attribute Summary (collapse)

• - (Object) attributes readonly

  :nodoc:.

Attributes inherited from Prawn::Font

#family, #name, #options

Class Method Summary (collapse)

• + (Object) metrics_path

Instance Method Summary (collapse)

• - (Object) bbox

  The font bbox, as an array of integers.

• - (Object) character_count(str)

  Returns the number of characters in str (a WinAnsi-encoded string).

• - (Object) compute_width_of(string, options = {})

  NOTE: String must be encoded as WinAnsi.

• - (Object) encode_text(text, options = {})

  Perform any changes to the string that need to happen before it is rendered to the canvas.

• - (Boolean) glyph_present?(char)
• - (Boolean) has_kerning_data?

  Returns true if the font has kerning data, false otherwise.

• - (AFM) initialize(document, name, options = {}) constructor

  :nodoc:.

• - (Object) normalize_encoding(text)

  built-in fonts only work with winansi encoding, so translate the string.

• - (Boolean) unicode?

Methods inherited from Prawn::Font

#add_to_current_page, #ascender, #descender, #height, #height_at, #identifier_for, #inspect, #line_gap, load, #normalize_encoding!

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# File 'lib/prawn/font/afm.rb', line 38

def initialize(document, name, options={}) #:nodoc:
  unless BUILT_INS.include?(name)
    raise Prawn::Errors::UnknownFont, "#{name} is not a known font."
  end

  super

  @@winansi   ||= Prawn::Encoding::WinAnsi.new # parse data/encodings/win_ansi.txt once only
  @@font_data ||= SynchronizedCache.new        # parse each ATM font file once only

  file_name = @name.dup
  file_name << ".afm" unless file_name =~ /\.afm$/
  file_name = file_name[0] == ?/ ? file_name : find_font(file_name)

  font_data = @@font_data[file_name] ||= ::AFM::Font.new(file_name)
  @glyph_table     = build_glyph_table(font_data)
  @kern_pairs      = font_data.kern_pairs
  @kern_pair_table = build_kern_pair_table(@kern_pairs)
  @attributes      = font_data.metadata

  @ascender  = @attributes["Ascender"].to_i
  @descender = @attributes["Descender"].to_i
  @line_gap  = Float(bbox[3] - bbox[1]) - (@ascender - @descender)
end

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# File 'lib/prawn/font/afm.rb', line 36

def attributes
  @attributes
end

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# File 'lib/prawn/font/afm.rb', line 24

def self.metrics_path
  if m = ENV['METRICS']
    @metrics_path ||= m.split(':')
  else
    @metrics_path ||= [
      ".", "/usr/lib/afm",
      "/usr/local/lib/afm",
      "/usr/openwin/lib/fonts/afm",
       Prawn::DATADIR+'/fonts']
  end
end

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# File 'lib/prawn/font/afm.rb', line 65

def bbox
  @bbox ||= @attributes['FontBBox'].split(/\s+/).map { |e| Integer(e) }
end

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# File 'lib/prawn/font/afm.rb', line 102

def character_count(str)
  str.length
end

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# File 'lib/prawn/font/afm.rb', line 70

def compute_width_of(string, options={}) #:nodoc:
  scale = (options[:size] || size) / 1000.0

  if options[:kerning]
    strings, numbers = kern(string).partition { |e| e.is_a?(String) }
    total_kerning_offset = numbers.inject(0.0) { |s,r| s + r }
    (unscaled_width_of(strings.join) - total_kerning_offset) * scale
  else
    unscaled_width_of(string) * scale
  end
end

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# File 'lib/prawn/font/afm.rb', line 118

def encode_text(text, options={})
  [[0, options[:kerning] ? kern(text) : text]]
end

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# File 'lib/prawn/font/afm.rb', line 122

def glyph_present?(char)
  if char == "_"
    true
  else
    normalize_encoding(char) != "_"
  end
end

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# File 'lib/prawn/font/afm.rb', line 84

def has_kerning_data?
  @kern_pairs.any?
end

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# File 'lib/prawn/font/afm.rb', line 92

def normalize_encoding(text) 
  enc = @@winansi
  text.unpack("U*").collect { |i| enc[i] }.pack("C*")
rescue ArgumentError
  raise Prawn::Errors::IncompatibleStringEncoding,
    "Arguments to text methods must be UTF-8 encoded"
end

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# File 'lib/prawn/font/afm.rb', line 20

def unicode?
  false
end