createCanvas(windowWidth, windowHeight);

  background(255,255,255); 

  frameRate(60); // this line will adjust how fast the draw() background repeats

} // end of the setup() function

​

function draw() { 

​

}

​

function mouseDragged() {

  noStroke(); 

  fill(0,0,0, 20);

  ellipse(mouseX, mouseY, 40, 40);

}

​

function doubleClicked() {

  save('my_drawing.png');

}