import megamu.shapetween.*;

Tween ani;
Shaper cosine;
void setup(){
  ani = new Tween(this, 2);
  cosine = new CosineShaper( Tween.IN );
}

void draw(){
  background(255);
  
  if( playCount()%2 == 0 ) // if the play count is even
  	ani.setEasing( cosine );
  else
  	ani.setEasing( "myCustomEasing" );
  
  ellipse(ani.time()*width, ani.position()*height, 4, 4);
}

void myCustomEasing(float in){
	return 1 - (1-in)*(1-in);
}

shape

Shaper function used for animation easing

easeMode

Optionally sets the ease direction for this shape,
Tween.IN, Tween.OUT, Tween.IN_OUT, Tween.OUT_IN

Class

Creates an instance of this class to use as Shaper. The Shaper constants.
ani.setEasing( Tween.COSINE )

Shaper

Uses this instance of a Shaper.
ani.setEasing( new CosineShaper() )

String

Uses this method found in the processing applet. The method should have one float parameter which will be a number between 0 and 1

ani.setEasing( "customEasing" );

void customEasing( float in ){
	return 1 - (1-in)*(1-in);
}