There are two modes for animating in Ferret. One can animate "on the fly" in an interactive sesion, or a sequence of Ferret plots can be stored and then animated. A series of gif images can also be animated, see Ch5 Sec1.2 below.
Formerly we had a method using an HDF file type. NOTE that starting with Ferret v6.6 HDF movies are no longer available.
5.1.1 Animating on the fly
In a Ferret session, display an animation with the command,
yes? REPEAT/ANIMATE[/LOOP=n]
to start an animation sequence. Given LOOP=n, the entire animation sequence will repeat n times.
Example:
yes? set data coads_climatology
yes? repeat/l=1:12/animate/loop=5 (shade sst; go fland)
NOTE: In order to properly display, it is necessary to have backing store enabled for the Xserver.
5.1.2 Note on using a set of gif images to make a movie
An easy way to make movies from gif files using third-party tools to generate an animation from a set of gif (png) images.
One such tool is gifsicle, http://www.lcdf.org/gifsicle/ free unix-based software that works well for creating animations from a set of gif images. No doubt there are other similar tools. The procedure for creating a set of Ferret gif images would be the same; see the documentation of gifsicle or other tools for how to use them to create the animation.
gfsicle is extremely easy to use:
1. Make your gif files with a Ferret command like:
yes? REPEAT/J=1:36 (GO scriptfile `j`; FRAME/FILE=sst-`j`.gif)
where the scriptfile uses the argument j to determine the plot characteristics. See sections later in this chapter for more on the REPEAT command and creating GIF files.
2. To create an animated gif (using just one example from the gifsicle website), from the Unix command line:
> gifsicle --delay=10 --loop sst*.gif > anim.gif
This file can be as long as you want and may specify files more than once to repeat any of the images if you wish.
That's it. The tool concatenates the gif files with some connecting information needed to do the animation. The resulting movie gif file is just about as large as the sum of the input frames.