function setup(){
createCanvas(600,600);
rectMode(CENTER);
background(0);
}
function draw(){
push();
translate(100,300);
scale(map(mouseX,0,300,0,1));
ellipse(0,0,50,50);
pop();
push();
translate(300,300);
scale(map(mouseX,0,300,0,3));
ellipse(0,0,100,100);
pop();
push();
translate(500,300);
scale(map(mouseX,0,300,0,5));
ellipse(0,0,30,30);
pop();
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/1.1.9/p5.min.js"></script>