MinimalTemplate

var gB, fullRes, windowRes;

var requiredFrames = 120;

​

function setup() {

  windowRes = min(windowWidth, windowHeight);

  createCanvas(windowRes, windowRes);

  imageMode(CENTER);

  gB = createGraphics(fullRes = 1024, fullRes);

  gB.colorMode(HSB, 360);

}

​

function draw() {

  gB.clear();

  gB.resetMatrix();

  gB.translate(fullRes * 0.5, fullRes * 0.5);

  gB.stroke(0);

  gB.noFill();

  var animationProgress = (frameCount / requiredFrames) % 1;

  gB.ellipse(0, 0, map(cos(animationProgress * TAU), -1, 1, fullRes * 0.25, fullRes * 0.75));

  background(360);

  displayBuffer(gB);

}

​

function keyPressed() {

  if (key === "g") {

    saveGif('export', requiredFrames, {delay: 0, units: "frames"});

  }

}

​

function displayBuffer(buffer) {

  image(buffer, windowRes/2, windowRes/2, windowRes, windowRes);

}

​

function windowResized() {

  windowRes = min(windowWidth, windowHeight);

  createCanvas(windowRes, windowRes);

}