Class: PDF::Reader::WidthCalculator::BuiltIn

Inherits:
Object
  • Object
show all
Defined in:
lib/pdf/reader/width_calculator/built_in.rb

Overview

Type1 fonts can be one of 14 “built in” standard fonts. In these cases, the reader is expected to have it’s own copy of the font metrics. see Section 9.6.2.2, PDF 32000-1:2008, pp 256

Constant Summary collapse

BUILTINS = 
[
  :Courier, :"Courier-Bold", :"Courier-BoldOblique", :"Courier-Oblique",
  :Helvetica, :"Helvetica-Bold", :"Helvetica-BoldOblique", :"Helvetica-Oblique",
  :Symbol,
  :"Times-Roman", :"Times-Bold", :"Times-BoldItalic", :"Times-Italic",
  :ZapfDingbats
]

Instance Method Summary collapse

Constructor Details

#initialize(font) ⇒ BuiltIn

Returns a new instance of BuiltIn.



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# File 'lib/pdf/reader/width_calculator/built_in.rb', line 23

def initialize(font)
  @font = font
  @@all_metrics ||= PDF::Reader::SynchronizedCache.new

  basefont = extract_basefont(font.basefont)
  metrics_path = File.join(File.dirname(__FILE__), "..","afm","#{basefont}.afm")

  if File.file?(metrics_path)
    @metrics = @@all_metrics[metrics_path] ||= AFM::Font.new(metrics_path)
  else
    raise ArgumentError, "No built-in metrics for #{font.basefont}"
  end
end

Instance Method Details

#glyph_width(code_point) ⇒ Object 



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# File 'lib/pdf/reader/width_calculator/built_in.rb', line 37

def glyph_width(code_point)
  return 0 if code_point.nil? || code_point < 0

  m = @metrics.char_metrics_by_code[code_point]
  if m.nil?
    names = @font.encoding.int_to_name(code_point)

    m = names.map { |name|
      @metrics.char_metrics[name.to_s]
    }.compact.first
  end

  if m
    m[:wx]
  elsif @font.widths[code_point - 1]
    @font.widths[code_point - 1]
  elsif control_character?(code_point)
    0
  else
    0
  end
end