• 円周上を公転するように動く丸

window.addEventListener("load", init);

function init() {
  var stage = new createjs.Stage("myCanvas");
  //
  var ball = new createjs.Shape();
  ball.graphics.beginFill('#888888').drawCircle(0, 0, 10);
  stage.addChild(ball);
  //
  var angle = 0;
  var centerX = stage.canvas.width / 2;
  var centerY = stage.canvas.height / 2;
  var radius = 100;
  var speed = .01;
  // 時間経過
  createjs.Ticker.addEventListener("tick", handleTick);
  function handleTick() {
    ball.x = centerX + Math.cos(angle) * radius;
    ball.y = centerY + Math.sin(angle) * radius;
    angle += speed;
    stage.update(); // 画面更新
  }
  //
  var bg = new createjs.Shape();
  bg.graphics.setStrokeStyle(1).beginStroke("LightGray").drawCircle(centerX, centerY, radius);
  stage.addChildAt(bg, 0);

  createjs.Ticker.timingMode = createjs.Ticker.RAF;
}