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

I wrote a blog post that doubles as semi-documentation for this script.

Call me lazy, but I'm looking forward to "a Web front end on this functionality" :)

Is there a way to convert all the gif-files in a folder?
I have 158 folders with about 12 gif each to convert...
https://github.com/frankkienl/BronyLiveWallpaper/tree/master/BronyLiveWallpaper/src/main/assets

Btw, I'm not using a WebView, but this library:
https://code.google.com/p/android-gifview/
Its okay, I guess, bit memory-hungry.
But your solution sounds a lot better ;-)

@frankkienl: I updated the script so -i accepts a directory or an individual GIF.

And, since comments here do not trigger GitHub notifications (grrrrr...), please use StackOverflow for further questions about this script. Tag your question with commonsware (in addition to android or ruby, whichever is more applicable to your question).

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.