class PDF::Reader::WidthCalculator::BuiltIn

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

Public Class Methods

new(font) click to toggle source
# File lib/pdf/reader/width_calculator/built_in.rb, line 63
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

Public Instance Methods

glyph_width(code_point) click to toggle source
# File lib/pdf/reader/width_calculator/built_in.rb, line 76
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