Hello @EKEN ,
You can also do a search here for easing:
https://processing.org/
Example on Processing site with description:
https://processing.org/examples/easing.html
Take a look at this example:
The easing in example above is the same as yours except that it eases across the screen with a keyPressed() and expanded below:
void keyPressed()
  {
  targetX = width;
  float dx = targetX-x;  
  x += dx*easing;
  println(x, easing, targetX); // Very useful to print values to console
  }
:)