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

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 64

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

  metrics_path = File.join(File.dirname(__FILE__), "..","afm","#{font.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 77

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]
  else
    raise ArgumentError, "Unknown glyph width for #{code_point} #{@font.basefont}"
  end
end