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# coding: utf-8
# frozen_string_literal: true
require 'afm'
require 'pdf/reader/synchronized_cache'
class PDF::Reader
module WidthCalculator
# 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
class BuiltIn
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
]
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
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
private
def control_character?(code_point)
@font.encoding.int_to_name(code_point).first.to_s[/\Acontrol..\Z/]
end
def extract_basefont(font_name)
if BUILTINS.include?(font_name)
font_name
else
"Times-Roman"
end
end
end
end
end
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