class Prawn::Font::AFM
@private
Constants
- BUILT_INS
Attributes
Public Class Methods
# File lib/prawn/font/afm.rb, line 32 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
Public Instance Methods
The font bbox, as an array of integers
# File lib/prawn/font/afm.rb, line 74 def bbox @bbox ||= @attributes['fontbbox'].split(/\s+/).map { |e| Integer(e) } end
Returns the number of characters in str
(a WinAnsi-encoded string).
# File lib/prawn/font/afm.rb, line 117 def character_count(str) str.length end
Perform any changes to the string that need to happen before it is rendered to the canvas. Returns an array of subset “chunks”, where each chunk is an array of two elements. The first element is the font subset number, and the second is either a string or an array (for kerned text).
For Adobe fonts, there is only ever a single subset, so the first element of the array is “0”, and the second is the string itself (or an array, if kerning is performed).
The text
parameter must be in WinAnsi encoding (cp1252).
# File lib/prawn/font/afm.rb, line 133 def encode_text(text, options={}) [[0, options[:kerning] ? kern(text) : text]] end
# File lib/prawn/font/afm.rb, line 137 def glyph_present?(char) !!normalize_encoding(char) rescue Prawn::Errors::IncompatibleStringEncoding false end
Returns true if the font has kerning data, false otherwise
# File lib/prawn/font/afm.rb, line 93 def has_kerning_data? @kern_pairs.any? end
built-in fonts only work with winansi encoding, so translate the string. Changes the encoding in-place, so the argument itself is replaced with a string in WinAnsi encoding.
# File lib/prawn/font/afm.rb, line 101 def normalize_encoding(text) text.encode("windows-1252") rescue ::Encoding::InvalidByteSequenceError, ::Encoding::UndefinedConversionError raise Prawn::Errors::IncompatibleStringEncoding, "Your document includes text that's not compatible with the Windows-1252 character set.\n"+ "If you need full UTF-8 support, use TTF fonts instead of PDF's built-in fonts\n." end
# File lib/prawn/font/afm.rb, line 111 def to_utf8(text) text.encode("UTF-8") end
# File lib/prawn/font/afm.rb, line 28 def unicode? false end
Private Instance Methods
# File lib/prawn/font/afm.rb, line 160 def find_font(file) self.class.metrics_path.find { |f| File.exist? "#{f}/#{file}" } + "/#{file}" rescue NoMethodError raise Prawn::Errors::UnknownFont, "Couldn't find the font: #{file} in any of:\n" + self.class.metrics_path.join("\n") end
converts a string into an array with spacing offsets bewteen characters that need to be kerned
String must be encoded as WinAnsi
# File lib/prawn/font/afm.rb, line 228 def kern(string) kerned = [[]] last_byte = nil string.each_byte do |byte| if k = last_byte && @kern_pair_table[[last_byte, byte]] kerned << -k << [byte] else kerned.last << byte end last_byte = byte end kerned.map { |e| e = (Array === e ? e.pack("C*") : e) e.respond_to?(:force_encoding) ? e.force_encoding(::Encoding::Windows_1252) : e } end
# File lib/prawn/font/afm.rb, line 168 def parse_afm(file_name) data = {:glyph_widths => {}, :bounding_boxes => {}, :kern_pairs => {}, :attributes => {}} section = [] File.foreach(file_name) do |line| case line when /^Start(\w+)/ section.push $1 next when /^End(\w+)/ section.pop next end case section when ["FontMetrics", "CharMetrics"] next unless line =~ /^CH?\s/ name = line[/\bN\s+(\.?\w+)\s*;/, 1] data[:glyph_widths][name] = line[/\bWX\s+(\d+)\s*;/, 1].to_i data[:bounding_boxes][name] = line[/\bB\s+([^;]+);/, 1].to_s.rstrip when ["FontMetrics", "KernData", "KernPairs"] next unless line =~ /^KPX\s+(\.?\w+)\s+(\.?\w+)\s+(-?\d+)/ data[:kern_pairs][[$1, $2]] = $3.to_i when ["FontMetrics", "KernData", "TrackKern"], ["FontMetrics", "Composites"] next else parse_generic_afm_attribute(line, data) end end # process data parsed from AFM file to build tables which # will be used when measuring and kerning text data[:glyph_table] = (0..255).map do |i| data[:glyph_widths][Encoding::WinAnsi::CHARACTERS[i]].to_i end character_hash = Hash[Encoding::WinAnsi::CHARACTERS.zip((0..Encoding::WinAnsi::CHARACTERS.size).to_a)] data[:kern_pair_table] = data[:kern_pairs].inject({}) do |h,p| h[p[0].map { |n| character_hash[n] }] = p[1] h end data.each_value { |hash| hash.freeze } data.freeze end
# File lib/prawn/font/afm.rb, line 216 def parse_generic_afm_attribute(line, hash) line =~ /(^\w+)\s+(.*)/ key, value = $1.to_s.downcase, $2 hash[:attributes][key] = hash[:attributes][key] ? Array(hash[:attributes][key]) << value : value end
# File lib/prawn/font/afm.rb, line 145 def register(subset) font_dict = {:Type => :Font, :Subtype => :Type1, :BaseFont => name.to_sym} # Symbolic AFM fonts (Symbol, ZapfDingbats) have their own encodings font_dict.merge!(:Encoding => :WinAnsiEncoding) unless symbolic? @document.ref!(font_dict) end
# File lib/prawn/font/afm.rb, line 156 def symbolic? attributes["characterset"] == "Special" end
# File lib/prawn/font/afm.rb, line 249 def unscaled_width_of(string) string.bytes.inject(0) do |s,r| s + @glyph_table[r] end end