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About Franimate!
Franimate! is a program for animating fractals like the ones created
by Fractalina. The animations are defined by saying where it should
be at a few key points in time ("key frames").
If you want to see it in action now, go directly to the applet: Franimate!.
In order to describe where an animation goes Franimate! uses "key
frames". Each key frame is it's own Fractalina
window, describing the fractal that will be one of the frames that the
animation goes through. An animation must have at least two key
frames, the first and last frames of the animation, and can have more
in between, to give finer control over the animation.
Key frames are like check points: Franimate! can decide how to go between key
frames, but it must end up at each key frame in order.
The number of frames between each pair of key frames is supplied by
the user (see below). Thus Franimate! will
satisfy another constraint: not only will it always go through key
frames, but the distance, in frames, between them is specified.
Franimate! generates the frames between pairs of key frames by
linearly interpolation. That is, the change in parameters between the
key frames is equally divided among frames in between.
As an example, imagine having two key frames in which the only difference is
the placement of one transformation: in the first it's at (0,0), in the second
it's at (8,8). If one frame is between these key frames, it will have the
transformation at (4,4). Similarly, if there are three frames they will have
(2,2), (4,4), and, (6,6).
Adding and removing key frames:
When Franimate is started two key frames will pop up (labeled 1 and 2). For a
simple animation (which goes from one fractal directly to another) these are all
that's needed.
To add a key frame, enter the number of the frame just after the one
to be added in the text box right of "before:". Then press "Add Key
Frame". For instance, if you have key frames 1, 2, and 3, to add a key
frame between 2 and 3 enter "3" in the box and press the button. a new
key frame 3 will come up, and the old 3 will be moved to 4. (Another
way of looking at this: enter in the text box the number of the new
key frame.)
To remove a key frame, enter the number of the key frame to be removed
in the text box right of "number:", then press "Remove Key Frame".
Changing the number of iterations and size:
The size of the animation (in pixels, but not always real screen
pixels) can be changed from the Options window. To get the Options
window press the button labeled "Options" in the main control
panel. After you have changed values, remember to press "Accept", or
the new values won't be registered. When setting the size of the
animation, remember that the memory usage to store each frame goes up
as the square of the size (memory can be important on some systems).
Also in the Options window is the number of iterations per frame. Since each
iteration adds a point to the fractal, the number of iterations corresponds to
how complete the image is. A few thousand iterations is usually enough, but it
depends a lot on the fractal.
Choosing the number of frames:
There are two ways to choose the number of frames in between each pair of key
frames. If you want the same number of frames between each pair (or you only have
two key frames), set the number in the text box just right of "with". The
default is 4.
If you want to specify the number of frames between pairs of key
frames, press the "set up" button, and the Set Up Animation window
will pop up. Each key frame is listed, and in between each pair is a
text box. Enter the number of frames in between the two adjacent key
frames into this box . If you open the Set Up Animation window and
then change your mind, just press "cancel".
Making an animation:
Once the animation is set up it is easy to make it. If you have a Set Up Animation
window open, press the "Make Animation" button there. Otherwise, press the
"Make Animation" button in the main window. You will see each frame as it's
generated.
The play button and scrollbar:
To play back an animation after it has been made, press the "Play" button. The
scrollbar just above "Play" corresponds to which frame is being displayed. Notice
that the scrollbar moves while the animation is being played, and that you can set
the frame shown by changing the scrollbar.
Bounces and delay:
The "number of bounces per showing", and "delay between frames" can be found in the
Options window. The number of bounces is the
number of times the animation plays backwards or forwards (it will bounce back
and forth if this is more that 1). The frame delay is the amount of time to
sleep after playing a frame.
Dumping an animation to GIF files:
If the security manager allows file access (usually in the stand alone
program, but usually not in an applet) you can dump the frames of an
animation to GIF files. When the "GIF dump" button is pressed
Franimate! will try to dump each frame into a file called
frmn.gif, where n is the frame number. Once you have the
gif frame images you can use a utility such as GIFMerge to
combine them into an animated gif.a The gif dump function uses the
excellent GIFEncoder
class by Addam Doppelt.
Since each frame is stored as a Java Image, the memory requirements can
rise rapidly with the size of the animation. However, there is no set way that
Images are stored, so there is no way to know the memory usage. We have had the
most trouble with Unix systems, in which Images are stored in the X manager.
Interestingly memory doesn't seem to be an issue on PCs (including Macs). When
memory runs out each system handles it in it's own way. (Unix systems tend to
force the JVM to quit without a message.)
In the Options window you have to press "Accept" or the new values
won't register. This is not actually a bug, it's here so people won't
write about it.
If you find any bugs not listed here, please email the author.
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The Geometry Center Home Page
This page was created by Noah
Goodman.
Comments to:
webmaster@geom.umn.edu
Created: Sep 23 1996 ---
Last modified: Tue Oct 8 11:34:01 1996