Creating animated gifs using emacs-director

Creating a gif using this setup works like this:

1. Create an elisp file containing instructions for emacs-director to run.
2. Run emacs with this file and the emacs-director bootstrap file.
3. Capture the output with asciinema.
4. Convert the asciinema file to an animated gif using asciicast2gif.

I created a small Makefile to handle these steps, so all I need to do is write the instruction file and then use make to create the actual gif.

Let's create a really simple gif that says "Hello, World!".

This is divided into two parts: a director-bootstrap command that tells emacs-director some basic information about the environment, and the director-run section that contains a full list of instructions.

For the bootstrap we can either use an existing user directory - useful if things need to be setup a certain way - or use the tmp directory.

The fun part is all contained in director-run, which tells Emacs exactly which steps to follow. Let's say hello!

(director-bootstrap
 :user-dir "/tmp/director-demo")

(director-run
 :version 1
 :before-start (lambda ()
		 (switch-to-buffer (get-buffer-create "*say-hello*"))
		 (menu-bar-mode -1))
 :steps '((:type "Hello, World!"))
 :typing-style 'human
 :delay-between-steps 1
 :after-end (lambda () (kill-emacs 0))
 :on-error  (lambda () (kill-emacs 1)))

The :before-start section can be used to set up buffers, switch the major mode, and run any other code that we don't want to look like it is being typed.

Here's the Makefile I use:

%.gif: %.cast
    asciicast2gif $< $@

%.cast: %.el
    asciinema rec $@ -c 'emacs -nw -Q -l util/director-bootstrap.el -l $<'

Calling make hello-world.gif will convert a file called hello-world.el into a .cast file, which will then be turned into an animated gif.

The finished image looks like this:

There are a few little gotchas:

• The finished gif will be based on the size of terminal where make was executed. If you create the gif from a fullscreen terminal you'll end up with a pretty big image.
• This process uses the terminal version of Emacs, so showing things involving the gui is not possible.
• When running code in :before-start there will be a frame or two before it is executed which can look a little weird.

None of these detract from the overall package, and it's a really easy way to create animated gifs of Emacs behaviour.

We'll finish with a slightly more complex gif:

This uses the same director-bootstrap as before, but has a few more steps:

(director-run
 :version 1
 :before-start (lambda ()
		 (menu-bar-mode -1)
		 (switch-to-buffer (get-buffer-create "*say-hello*"))
		 (emacs-lisp-mode))
 :steps '((:type "(defun say-hello ()\r")
	  (:type "\"Say hello to the world.\"\r")
	  (:type "(interactive)\r")
	  (:type "(message \"Hello, World!\"))\r")
	  (:type "\C-x\C-e")
	  (:wait 2)
	  (:type "\M-x")
	  (:type "say-hello")
	  (:type [return]))
 :typing-style 'human
 :delay-between-steps 1
 :after-end (lambda () (sleep-for 5) (kill-emacs 0))
 :on-error  (lambda () (kill-emacs 1)))

Normally to create a gif like this I would type everything by hand and record the screen with licecap or recordMyDesktop, so being able to automate things is a huge time saver.