Ruby script to convert animated GIF into an Android AnimationDrawable

gif2animdraw

#!/usr/bin/ruby
require 'fileutils'
require 'RMagick'
require 'slop'
require 'builder'

opts = Slop.new do
  banner "gif2animdraw [options]\n"
  on :i, :input=, 'path to animated GIF (or directory of GIFs)', :required => true
  on :o, :outdir=, 'path to root output directory', :required => true
  on :d, :density=, 'density name to use for frames', :required=>true
  on :oneshot, 'if set, animation does not repeat', :required => false, :default=>false
  help
end

begin
  opts.parse
rescue
  puts opts.help
  exit -1
end

if !['ldpi', 'mdpi', 'tvdpi', 'hdpi', 'xhdpi', 'xxhdpi', 'xxxhdpi'].include?(opts[:d])
  puts "Invalid density #{opts[:d]}"
  exit -1
end

glob=File.directory?(opts[:i]) ? File.join(opts[:i], '*.gif') : opts[:i]

Dir[glob].each do |gif|
  input=Magick::ImageList.new(gif).coalesce
  output=File.join(opts[:o], 'drawable')
  output_density=File.join(opts[:o], 'drawable-'+opts[:d])
  basename=File.basename(gif, '.gif').downcase.gsub(/\W/,'_')

  FileUtils.mkdir_p output
  FileUtils.mkdir_p output_density

  Dir.glob(File.join(output_density, basename+'*.png')).each {|f| File.delete(f) }

  input.write File.join(output_density, basename+'_%d.png')

  builder = Builder::XmlMarkup.new(:indent=>2)

  builder.tag!('animation-list',
                'xmlns:android'=>'http://schemas.android.com/apk/res/android',
                'android:oneshot'=>opts[:oneshot]) do
    i=0
    input.each do |frame|
      builder.item('android:drawable'=>"@drawable/#{basename}_#{i}",
                    'android:duration'=>frame.delay*1000/input.ticks_per_second)
      i+=1
    end
  end

  open(File.join(output, basename+'.xml'), 'w') do |f|
    f.puts builder.target!
  end
end

If anyone else is still looking at this (no judgements), make sure you install slop 3, not the rewritten slop 4 which was rewritten and has broken changes.