TTC file support (#33)

Add support for TTC files

CHANGELOG.md

@@ -7,6 +7,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 
 ## [Unreleased]
 
+### Added
+
+* Support for reading TTF fonts from TTC files
+
 ### Changed
 
 * Subset font naming is consistent now and depends on content

lib/ttfunk.rb

@@ -3,6 +3,7 @@
 
 require_relative 'ttfunk/directory'
 require_relative 'ttfunk/resource_file'
+require_relative 'ttfunk/collection'
 
 module TTFunk
   class File
@@ -17,6 +18,10 @@ def self.from_dfont(file, which = 0)
       new(ResourceFile.open(file) { |dfont| dfont['sfnt', which] })
     end
 
+    def self.from_ttc(file, which = 0)
+      Collection.open(file) { |ttc| ttc[which] }
+    end
+
     def self.verify_and_open(io_or_path)
       # File or IO
       if io_or_path.respond_to?(:rewind)
@@ -36,9 +41,9 @@ def self.verify_and_open(io_or_path)
       io
     end
 
-    def initialize(contents)
+    def initialize(contents, offset = 0)
       @contents = StringIO.new(contents)
-      @directory = Directory.new(@contents)
+      @directory = Directory.new(@contents, offset)
     end
 
     def ascent

lib/ttfunk/collection.rb

@@ -0,0 +1,41 @@
+require 'ttfunk'
+
+module TTFunk
+  class Collection
+    include Enumerable
+
+    def self.open(path)
+      ::File.open(path, 'rb') do |io|
+        yield new(io)
+      end
+    end
+
+    def initialize(io)
+      tag = io.read(4)
+      raise ArgumentError, 'not a TTC file' unless tag == 'ttcf'
+
+      _major, _minor = io.read(4).unpack('n*')
+      count = io.read(4).unpack('N').first
+      @offsets = io.read(count * 4).unpack('N*')
+
+      io.rewind
+      @contents = io.read
+      @cache = []
+    end
+
+    def count
+      @offsets.length
+    end
+
+    def each
+      count.times do |index|
+        yield self[index]
+      end
+      self
+    end
+
+    def [](index)
+      @cache[index] ||= TTFunk::File.new(@contents, @offsets[index])
+    end
+  end
+end

lib/ttfunk/directory.rb

@@ -3,7 +3,8 @@ class Directory
     attr_reader :tables
     attr_reader :scaler_type
 
-    def initialize(io)
+    def initialize(io, offset = 0)
+      io.seek(offset)
       @scaler_type, table_count = io.read(12).unpack('Nn')
 
       @tables = {}

spec/integration/collection_spec.rb

@@ -0,0 +1,28 @@
+# coding: utf-8
+
+require 'spec_helper'
+
+describe TTFunk::Collection, '::open' do
+  it 'will not open non-TTC files' do
+    expect { TTFunk::Collection.open test_font('DejaVuSans') }
+      .to raise_error(ArgumentError)
+  end
+
+  it 'will open TTC files' do
+    success = false
+
+    TTFunk::Collection.open(test_font('DejaVuSans', :ttc)) do |_ttc|
+      success = true
+    end
+
+    expect(success).to be true
+  end
+
+  it 'will report fonts in TTC' do
+    TTFunk::Collection.open(test_font('DejaVuSans', :ttc)) do |ttc|
+      expect(ttc.count).to eq 2
+      expect(ttc[0].name.font_name.first).to eq 'DejaVu Sans'
+      expect(ttc[1].name.font_name.first).to eq 'DejaVu Sans Bold'
+    end
+  end
+end

spec/integration/file_spec.rb

@@ -13,6 +13,13 @@
   end
 end
 
+describe TTFunk::File, '::from_ttc' do
+  it 'returns font at requested index in TTC file' do
+    font = TTFunk::File.from_ttc(test_font('DejaVuSans', :ttc), 1)
+    expect(font.name.font_name.first).to eq 'DejaVu Sans Bold'
+  end
+end
+
 describe TTFunk::File, '#ascent' do
   context 'with DejaVuSans' do
     let!(:file) { TTFunk::File.open(test_font('DejaVuSans')) }

spec/support/path_helpers.rb

@@ -1,7 +1,7 @@
 module PathHelpers
-  def test_font(name)
+  def test_font(name, ext = :ttf)
     base_path = File.expand_path(File.dirname(__FILE__) + '/../fonts')
-    valid_filename = File.join(base_path, "#{name}.ttf")
+    valid_filename = File.join(base_path, "#{name}.#{ext}")
     if File.file?(valid_filename)
       return valid_filename
     else