Refactor AnimatedGif into a class rather than singleton methods.

lib/gd2-ffij.rb

@@ -187,14 +187,24 @@ def self.gd_library_name
   ALPHA_TRANSPARENT = 127
 
   class LibraryError < StandardError; end
-end
 
-require 'gd2/image'
-require 'gd2/color'
-require 'gd2/palette'
-require 'gd2/canvas'
-require 'gd2/font'
-require 'gd2/ffi_struct'
+  GD2_BASE = File.join(File.dirname(__FILE__), 'gd2')
+
+  autoload :Image,
+    File.join(GD2_BASE, 'image')
+  autoload :Color,
+    File.join(GD2_BASE, 'color')
+  autoload :Palette,
+    File.join(GD2_BASE, 'palette')
+  autoload :Canvas,
+    File.join(GD2_BASE, 'canvas')
+  autoload :Font,
+    File.join(GD2_BASE, 'font')
+  autoload :FFIStruct,
+    File.join(GD2_BASE, 'ffi_struct')
+  autoload :AnimatedGif,
+    File.join(GD2_BASE, 'animated_gif')
+end
 
 class Numeric
   if not self.instance_methods.include? 'degrees'

lib/gd2/animated_gif.rb

@@ -0,0 +1,79 @@
+# frozen_string_literal: true; encoding: ASCII-8BIT
+#
+# See COPYRIGHT for license details.
+
+class GD2::AnimatedGif
+  class Frame < Struct.new(:ptr, :size)
+    def read
+      ptr.get_bytes(0, size.get_int(0))
+    end
+  end
+
+  def add(ptr, options = {})
+    size = FFI::MemoryPointer.new(:int)
+
+    frame_ptr = if frames.empty?
+      ::GD2::GD2FFI.send(:gdImageGifAnimBeginPtr, ptr.image_ptr, size, -1, 0)
+    else
+      previous_frame_ptr = if options[:previous_frame]
+        options[:previous_frame].image_ptr
+      else
+        FFI::Pointer::NULL
+      end
+
+      ::GD2::GD2FFI.send(:gdImageGifAnimAddPtr, ptr.image_ptr, size, 0, 0, 0, options[:delay].to_i, 1, previous_frame_ptr)
+    end
+
+    raise LibraryError if frame_ptr.null?
+
+    frames << Frame.new(frame_ptr, size)
+  end
+
+  def end
+    size = FFI::MemoryPointer.new(:int)
+
+    frame_ptr = ::GD2::GD2FFI.send(:gdImageGifAnimEndPtr, size)
+
+    raise LibraryError if frame_ptr.null?
+
+    frames << Frame.new(frame_ptr, size)
+  end
+
+  def export(filename_or_io)
+    output = case filename_or_io
+      when String
+        File.open(filename_or_io, 'wb')
+      else
+        filename_or_io
+    end
+
+    frames.each do |frame|
+      output.write(frame.read)
+    end
+
+    output.flush
+    output.rewind
+
+    output
+  end
+
+  private
+
+    def frames
+      return @frames if defined?(@frames)
+
+      @frames = []
+
+      ObjectSpace.define_finalizer(@frames, frames_finalizer)
+
+      @frames
+    end
+
+    def frames_finalizer
+      proc do
+        each do |frame|
+          ::GD2::GD2FFI.send(:gdFree, frame[:frame_ptr])
+        end
+      end
+    end
+end

lib/gd2/image.rb

@@ -806,47 +806,4 @@ def sharpen(pct)  #:nodoc:
       self
     end
   end
-
-  #
-  # = Description
-  #
-  # AnimtedGif class represents methods to generate animated gif output
-  #
-
-  class AnimatedGif
-
-     def self.pal_copy(to, from)                  #:nodoc:
-       ::GD2::GD2FFI.send(:gdImagePaletteCopy, to.image_ptr, from.image_ptr)
-     end
-
-     def self.gif_anim_begin(ptr)                 #:nodoc:
-       size = FFI::MemoryPointer.new(:int)
-       ptr = ::GD2::GD2FFI.send(:gdImageGifAnimBeginPtr, ptr.image_ptr, size, -1, 0)
-       raise LibraryError if ptr.null?
-       ptr.get_bytes(0, size.get_int(0))
-     ensure
-       ::GD2::GD2FFI.send(:gdFree, ptr)
-     end
-
-     def self.gif_anim_add(ptr, prevptr, delay)   #:nodoc:
-       size = FFI::MemoryPointer.new(:int)
-       ptr = ::GD2::GD2FFI.send(:gdImageGifAnimAddPtr, ptr.image_ptr, size, 0, 0, 0, delay, 1,
-                                (prevptr.nil? ? FFI::Pointer::NULL : prevptr.image_ptr))
-       raise LibraryError if ptr.null?
-       ptr.get_bytes(0, size.get_int(0))
-     ensure
-       ::GD2::GD2FFI.send(:gdFree, ptr)
-     end
-
-     def self.gif_anim_end()                      #:nodoc:
-       size = FFI::MemoryPointer.new(:int)
-       ptr = ::GD2::GD2FFI.send(:gdImageGifAnimEndPtr, size)
-       raise LibraryError if ptr.null?
-       ptr.get_bytes(0, size.get_int(0))
-     ensure
-       ::GD2::GD2FFI.send(:gdFree, ptr)
-     end
-
-  end
-
 end

test/animated_gif_tests.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true; encoding: ASCII-8BIT
+
+require './test/test_helper'
+
+class AnimatedGifTest < Minitest::Test
+  include TestHelper
+
+  def test_animation
+    image1 = GD2::Image::IndexedColor.new(256, 256)
+
+    black = image1.palette.allocate(GD2::Color[0, 0, 0])
+    white = image1.palette.allocate(GD2::Color[255, 255, 255])
+    lime = image1.palette.allocate(GD2::Color[0, 255, 0])
+
+    image1.draw do |pen|
+      pen.color = white
+      pen.line(64, 64, 192, 192)
+    end
+
+    image2 = GD2::Image::IndexedColor.new(256, 256)
+    black = image2.palette.allocate(GD2::Color[0, 0, 0])
+    white = image2.palette.allocate(GD2::Color[255, 255, 255])
+    lime = image2.palette.allocate(GD2::Color[0, 255, 0])
+
+    image2.draw do |pen|
+      pen.color = lime
+      pen.rectangle(32, 64, 192, 192)
+    end
+
+    anim = GD2::AnimatedGif.new
+    anim.add(image1)
+    anim.add(image2, delay: 50)
+    anim.add(image1, delay: 50)
+    anim.end
+
+    output = StringIO.new
+
+    anim.export(output)
+
+    assert(output.read == File.read('test/images/test_animated_gif.gif'))
+  end
+end