Resize animated gif

[gitviola]

I tried resizing an animated gif but it messes up the animation after resizing. I found out that there are two steps required to resize an animated gif.

Example

convert do.gif -coalesce temporary.gif
convert -size <original size> temporary.gif -resize 24x24 smaller.gif

Is there a way to get a resized version of an animated gif with arc?

[stavro]

Are you sure that the above operation requires two calls to convert?

All of the examples here use one call to convert: http://www.imagemagick.org/Usage/anim_mods/#resize

eg: convert script_k.gif -coalesce -resize 20x20 script_k_direct2.gif

[gitviola]

I tried it with the parameters mentioned above:

def transform(:thumb, {file, _scope}) do
    file_extension = file.file_name |> Path.extname
    case file_extension do
      ".gif" -> {:convert, "-coalesce -resize 250x250 -gravity center -extent 250x250"}
      _      -> {:convert, "-strip -thumbnail 250x250 -gravity center -extent 250x250"}
    end
  end

  def transform(:medium, {file, _scope}) do
    file_extension = file.file_name |> Path.extname
    case file_extension do
      ".gif" -> {:convert, "-coalesce -resize 700x700"}
      _      -> {:convert, "-quality 80 -strip -thumbnail 700x700> -gravity center"}
    end
  end

It takes forever and after a while there is a timeout

** (UndefinedFunctionError) undefined function :timeout.__struct__/1 (module :timeout is not available)
        :timeout.__struct__({:timeout, {Task, :await, [%Task{owner: #PID<0.1684.0>, pid: #PID<0.1689.0>, ref: #Reference<0.0.1.26960>}, 15000]}})

[stavro]

This should be done through https://github.com/stavro/arc#complex-transformations for now.