processing4/java/examples/Basics/Input/Easing/applet/Easing.java

import processing.core.*; 

import java.applet.*; 
import java.awt.*; 
import java.awt.image.*; 
import java.awt.event.*; 
import java.io.*; 
import java.net.*; 
import java.text.*; 
import java.util.*; 
import java.util.zip.*; 
import java.util.regex.*; 

public class Easing extends PApplet {

/**
 * Easing. 
 * 
 * Move the mouse across the screen and the symbol will follow.  
 * Between drawing each frame of the animation, the program
 * calculates the difference between the position of the 
 * symbol and the cursor. If the distance is larger than
 * 1 pixel, the symbol moves part of the distance (0.05) from its
 * current position toward the cursor. 
 */
 
float x;
float y;
float targetX, targetY;
float easing = 0.05f;

public void setup() 
{
  size(200, 200); 
  smooth();
  noStroke();  
}

public void draw() 
{ 
  background( 51 );
  
  targetX = mouseX;
  float dx = mouseX - x;
  if(abs(dx) > 1) {
    x += dx * easing;
  }
  
  targetY = mouseY;
  float dy = mouseY - y;
  if(abs(dy) > 1) {
    y += dy * easing;
  }
  
  ellipse(x, y, 33, 33);
}

  static public void main(String args[]) {
    PApplet.main(new String[] { "Easing" });
  }
}