Add OpenType Fonts support

lib/prawn/font.rb

@@ -282,6 +282,7 @@ class Font
     require_relative 'fonts/afm'
     require_relative 'fonts/ttf'
     require_relative 'fonts/dfont'
+    require_relative 'fonts/otf'
     require_relative 'fonts/ttc'
 
     # @deprecated
@@ -305,9 +306,10 @@ class Font
     # Fonts::AFM.new()
     def self.load(document, src, options = {})
       case font_format(src, options)
-      when 'ttf'   then TTF.new(document, src, options)
+      when 'ttf' then TTF.new(document, src, options)
+      when 'otf' then Fonts::OTF.new(document, src, options)
       when 'dfont' then DFont.new(document, src, options)
-      when 'ttc'   then TTC.new(document, src, options)
+      when 'ttc' then TTC.new(document, src, options)
       else AFM.new(document, src, options)
       end
     end
@@ -317,6 +319,7 @@ def self.font_format(src, options)
 
       case src.to_s
       when /\.ttf$/i   then 'ttf'
+      when /\.otf$/i   then 'otf'
       when /\.dfont$/i then 'dfont'
       when /\.ttc$/i   then 'ttc'
       else 'afm'

lib/prawn/fonts/afm.rb

@@ -97,9 +97,11 @@ def compute_width_of(string, options = {}) #:nodoc:
 
       # Returns true if the font has kerning data, false otherwise
       #
+      # rubocop: disable Naming/PredicateName
       def has_kerning_data?
         @kern_pairs.any?
       end
+      # rubocop: enable Naming/PredicateName
 
       # built-in fonts only work with winansi encoding, so translate the
       # string. Changes the encoding in-place, so the argument itself
@@ -113,8 +115,8 @@ def normalize_encoding(text)
         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 external fonts instead of PDF's " \
-          "built-in fonts.\n"
+          'If you need full UTF-8 support, use external fonts instead of ' \
+          "PDF's built-in fonts.\n"
       end
 
       def to_utf8(text)

lib/prawn/fonts/otf.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require_relative 'ttf'
+
+module Prawn
+  module Fonts
+    # @private
+    class OTF < TTF
+    end
+  end
+end

lib/prawn/fonts/ttf.rb

@@ -62,9 +62,12 @@ def bbox
       end
 
       # Returns true if the font has kerning data, false otherwise
+      #
+      # rubocop: disable Naming/PredicateName
       def has_kerning_data?
         @has_kerning_data
       end
+      # rubocop: enable Naming/PredicateName
 
       # Perform any changes to the string that need to happen
       # before it is rendered to the canvas. Returns an array of

lib/prawn/text.rb

@@ -294,7 +294,7 @@ def draw_text!(text, options)
       unless font.unicode? || font.class.hide_m17n_warning || text.ascii_only?
         warn "PDF's built-in fonts have very limited support for " \
              "internationalized text.\nIf you need full UTF-8 support, " \
-             "consider using a TTF font instead.\n\nTo disable this " \
+             "consider using an external font instead.\n\nTo disable this " \
              "warning, add the following line to your code:\n" \
              "Prawn::Fonts::AFM.hide_m17n_warning = true\n"
 

lib/prawn/text/box.rb

@@ -61,7 +61,7 @@ module Text
     #     or right-to-left) [value of document.text_direction]
     # <tt>:fallback_fonts</tt>::
     #     An array of font names. Each name must be the name of an AFM font or
-    #     the name that was used to register a family of TTF fonts (see
+    #     the name that was used to register a family of external fonts (see
     #     Prawn::Document#font_families). If present, then each glyph will be
     #     rendered using the first font that includes the glyph, starting with
     #     the current font and then moving through :fallback_fonts from

manual/text/line_wrapping.rb

@@ -5,7 +5,8 @@
 # display space without allowing for a break.
 #
 # For writing styles that do not make use of spaces, the zero width space serves
-# to mark word boundaries. Zero width spaces are available only with TTF fonts.
+# to mark word boundaries. Zero width spaces are available only with external
+# fonts.
 
 require_relative '../example_helper'
 

manual/text/registering_families.rb

@@ -12,7 +12,7 @@
 
 filename = File.basename(__FILE__).gsub('.rb', '.pdf')
 Prawn::ManualBuilder::Example.generate(filename) do
-  # Registering a single TTF font
+  # Registering a single external font
   font_families.update(
     'DejaVu Sans' => {
       normal: "#{Prawn::DATADIR}/fonts/DejaVuSans.ttf"

manual/text/utf8.rb

@@ -17,7 +17,7 @@
 
   move_down 20
 
-  text 'For full internationalized text support, we need to use TTF fonts:'
+  text 'For full internationalized text support, we need to use external fonts:'
   move_down 20
 
   font("#{Prawn::DATADIR}/fonts/DejaVuSans.ttf") do

prawn.gemspec

@@ -37,7 +37,7 @@ Gem::Specification.new do |spec|
   spec.licenses = %w[PRAWN GPL-2.0 GPL-3.0]
 
   spec.add_dependency('pdf-core', '~> 0.8.1')
-  spec.add_dependency('ttfunk', '~> 1.5')
+  spec.add_dependency('ttfunk', '~> 1.6')
 
   spec.add_development_dependency('pdf-inspector', '>= 1.2.1', '< 2.0.a')
   spec.add_development_dependency('pdf-reader', ['~> 1.4', '>= 1.4.1'])

spec/prawn/font_spec.rb

@@ -457,6 +457,37 @@ def page_should_not_include_font(font)
     end
   end
 
+  describe 'OTF fonts' do
+    let(:font) { pdf.find_font "#{Prawn::DATADIR}/fonts/Bodoni-Book.otf" }
+
+    it 'calculates string width taking into account accented characters' do
+      expect(font.compute_width_of('é', size: 12)).to eq(
+        font.compute_width_of('e', size: 12)
+      )
+    end
+
+    it 'uses the ascender, descender, and cap height from the OTF verbatim' do
+      # These metrics are relative to the font's own bbox. They should not be
+      # scaled with font size.
+      ref = pdf.ref!({})
+      font.send :embed, ref, 0
+
+      # Pull out the embedded font descriptor
+      descriptor = ref.data[:FontDescriptor].data
+      expect(descriptor[:Ascent]).to eq(1023)
+      expect(descriptor[:Descent]).to eq(-200)
+      expect(descriptor[:CapHeight]).to eq(3072)
+    end
+
+    describe 'when normalizing encoding' do
+      it 'does not modify the original string with normalize_encoding()' do
+        original = 'Foo'
+        normalized = font.normalize_encoding(original)
+        expect(original).to_not be_equal(normalized)
+      end
+    end
+  end
+
   describe 'DFont fonts' do
     let(:file) { "#{Prawn::DATADIR}/fonts/Panic+Sans.dfont" }
 

spec/prawn_manual_spec.rb

@@ -6,11 +6,11 @@
 MANUAL_HASH =
   case RUBY_ENGINE
   when 'ruby'
-    '85d2ded146d1e6659e9db389a071896d6e57d7cc4210c6b7fc75fc4afe2b5697'\
-    '8a86baca785acd717964619dc234327ef59f5ba6d750dfd626279af0166f6c5e'
+    'b38bd8aaa7b419a2f594ee8837cd62f813141000393995b0c0456644b823a62a'\
+    '2f8031b2db0fc9e7c544b3946a9b0e60570d510564e6fed3931e0717dd49188a'
   when 'jruby'
-    '85d2ded146d1e6659e9db389a071896d6e57d7cc4210c6b7fc75fc4afe2b5697'\
-    '8a86baca785acd717964619dc234327ef59f5ba6d750dfd626279af0166f6c5e'
+    'b38bd8aaa7b419a2f594ee8837cd62f813141000393995b0c0456644b823a62a'\
+    '2f8031b2db0fc9e7c544b3946a9b0e60570d510564e6fed3931e0717dd49188a'
   end
 
 RSpec.describe Prawn do