​

function setup() {

  createCanvas(400, 400);

  noStroke();

  background(0);

  console.log("use: \nmouseWheel for  brush size\nmouse button pressed: \nLEFT paint white\nRIGHT erase\nWHEEL for clear");

}

​

function draw() {

  if (mouseButton === RIGHT)   fill(0);

  if (mouseButton === LEFT)    fill(255);

  if (mouseButton === CENTER)  background(0);

  if (mouseIsPressed)          ellipse(mouseX, mouseY, brush, brush);

}

​

function mouseWheel(event) {

  brush += event.delta;

  brush = constrain(brush, 1, width / 2);

  print("brush: " + brush);

}

​

document.oncontextmenu = function() {

  return false;

}