​

// Create a variable for your Checkbox

let cb1;

​

function setup() {

  createCanvas(400, 400);

  gui = createGui();

  // Create Checkbox

  cb1 = createCheckbox("Checkbox", 150, 50, 100, 100);

}

​

function draw() {

  background(220);

  drawGui();

  if (cb1.isPressed) {

    // Print a message when Checkbox is pressed

    // that displays its value.

    print(cb1.label + " is " + cb1.val);

  }

  if (cb1.val) {

    // Draw an ellipse when Checkbox is true.

    fill(255, 0, 0);

    ellipse(200, 300, 100);

  }

}

​

/// Add these lines below sketch to prevent scrolling on mobile

function touchMoved() {

  // do some stuff

  return false;

}