​

function setup() {

  createCanvas(600,600);

}

​

function draw() {

  background(250);

  //bar

  fill(250)

  stroke(0)

  rectMode(CENTER);

  rect(300,300,360,20,15);

​

  //button

  noStroke()

  fill(0,0,250);

  ellipse(x,300,40);

​

  //right slide

  if(mouseIsPressed && mouseX > x) {

    x = constrain(mouseX, 120, 465);

    //left slide

  } else if (mouseIsPressed && mouseX<x) {

    x = constrain(mouseX,135,465)

  }

}

​