1. by Pixer and Didney Animation Studios
How to Animate 101
by Pixer and Didney Animation Studios

2. Compiling, Running, and Quitting
To compile (this will compile any .java files Animate uses):
javac -cp objectdraw.jar:. Animate.java
To run (this will require all the .class files Animate uses):
java -cp objectdraw.jar:. Animate
To quit (because the X11 window does not have a close button):
Ctrl-C (entered into the terminal)

3. The Basics of Animation
Animation is a series of still images that are shown very quickly
To animate something on a computer:
Move object to new location
Pause for a very short time
Repeat steps 1 and 2
The shorter the pause and the smaller the movement, the smoother the animation will be
Longer pauses will make the animation seem jerky
Making movements bigger or pauses shorter will make the animation faster

4. The Structure of Objectdraw Animation
Two major components: WindowController and Thread
Both must be EXTENDED by another class
public class Animate extends WindowController {...}
public class DrawArc extends Thread {...}
The WindowController will create new Threads in the begin() method
The animation logic is written in the Thread’s run() method
In the files we gave you, Animate is the WindowController, and it creates a new Thread, DrawArc

5. WindowController
The driver for all the threads - where all new Threads are created
Requires a begin() method, and inside it you want to:
Inherit a canvas so the objects know what to draw themselves on
DrawingCanvas myCanvas = canvas;
Create a new thread and start it, giving them the canvas that we have
Thread t1 = new DrawArc(0, 0, myCanvas);
t1.start();

6. Animate.java
In addition to the standard WindowController methods, Animate has two additional methods
catchSleep(): a static function that pauses the program for a few millisections
call this in Thread.run() after every movement, otherwise you won’t see the animation because movements happen instantly
main(): where the program starts - this is a little confusing because inside of it you create an instance of Animate
See slide 8 for clarification of program flow

7. Thread (aka DrawArc.java)
Where the animation actually happens
Requires a constructor and a run() method
Constructor sets up variables and objects (FilledArc, FilledRect, etc)
arc = new FilledArc(..., canvas); //give this the canvas!
run() does two things in a loop:
Moves your object
arc.move(x, y);
Pauses the animation so the user can see the progress of the object
Animate.catchSleep(milliseconds);
You DO NOT call run() anywhere!
Run is automatically called by Thread.start(), which you called in Animate

8. ANIMATION.JAVA
DRAWARC.JAVA
FILLEDARC.JAVA
1. Animation.main() creates a new Animation and runs
3. DrawArc(), which creates other objects by calling
4. FilledArc(), which is the object being moved in DrawArc
2. Animation.begin() creates multiple threads, calling
5. Then starts these threads calling Thread.start(), which automatically calls
6. DrawArc.run(), which loops between first moving the object by calling
8. and then calling
7. FilledArc.move(), which moves this specific object
TO PROGRAM YOUR OWN ANIMATIONS, swap out DrawArc.java and FilledArc.java with your own classes and program your own animation logic
Ex. MoveSquareUpAndDown.java which uses FilledRect.java
9. Animation.catchSleep() to pause the thread

9. TL;DR Do NOT change Animate.main() or Animate.catchSleep()
Create instances of animations (threads) in Animate.begin();
These are your own animations that EXTEND Thread
These require a constructor and a run() method
Creation of objects like squares/circles/lines is in constructor
Movement/pausing loop happens in run()
For a summary of objects you can use - aka circles/squares/lines, look at the left column of this library:

10. GOOD LUCK
Albert