let x = 100;

​

function setup() {

  createCanvas(400, 400);

  extraCanvas = createGraphics(400, 400);

}

​

function draw() {

  background(0);

  extraCanvas.background(255, 0, 0);

  extraCanvas.fill(0,0,255);

  extraCanvas.rect(100, 100, 50, 50);

​

  let col = extraCanvas.get(mouseX, mouseY);

  console.log(col);

​

  // image(extraCanvas,0,0);

  fill(255);

  ellipse(mouseX, mouseY, 32);

}