tween/example.html at master · moon/tween · GitHub

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<!DOCTYPE html>
<html>
<head>
  <title>Tween Example</title>
  <style type="text/css">
    html, body {
      background: #1A1B1B;
      margin: 0;
    }
    #ui {
      position: absolute;
      right: 20px;
      top: 20px;
    }
  </style>
</head>
<body>
  <canvas id="canvas"></canvas>
  <div id="ui">
    <button id="toggle">Toggle</button>
  </div>
  <script src="tween.js"></script>
  <script>

    var BACKGROUND_COLOR = '#1A1B1B';
    var DOT_COLOR = '#F6F7EA';
    var EQUATIONS = [
      'Linear',
      'Elastic',
      'Bounce',
      'Back',
      'Sine',
      'Circ',
      'Expo',
      'Quad',
      'Cubic',
      'Quart',
      'Quint'
    ];

    var canvas = document.getElementById('canvas');
    var context = canvas.getContext('2d');
    var dots = [];

    var height = canvas.height = window.innerHeight;
    var width = canvas.width = window.innerWidth;

    function setup() {

      var space = width * 0.8;
      var start = (width - space) / 2;
      var total = EQUATIONS.length * 3;
      var step = space / total;

      context.fillStyle = BACKGROUND_COLOR;
      context.fillRect(0, 0, width, height);

      EQUATIONS.forEach(function(name, index) {
        x = start + (step / 2) + index * 3 * step;
        dots.push(
          makeDot(x, Tween[name].in),
          makeDot(x + step, Tween[name].out),
          makeDot(x + step * 2, Tween[name].inOut)
        );
      });

      initUI();
      update();
    }

    function initUI() {
      var toggle = document.getElementById('toggle');
      toggle.addEventListener('click', function() {
        dots.forEach(function(dot) {
          if (!dot.tween.paused) {
            dot.tween.pause();
          } else {
            dot.tween.play();
          }
        });
      });
    }

    function makeDot(x, ease) {
      var dot = {
        radius: 5,
        ease: ease,
        x: x,
        y: height * 0.2
      };
      dot.animate = animate.bind(dot);
      dot.animate();
      return dot;
    }

    function animate() {

      var position = height * (this.y > height/2 ? 0.2 : 0.8);

      this.tween =

        Tween.to(this, 1.5, { y: position })

          .wait(0.0)            // optional delay
          .ease(this.ease)      // optional easing function
          .start(function() {}) // add start callback
          .step(function() {})  // add step callback
          .done(this.animate);  // add done callback
    }

    function update() {
      requestAnimationFrame(update);
      context.fillStyle = BACKGROUND_COLOR;
      context.globalAlpha = 0.3;
      context.fillRect(0, 0, width, height);
      context.beginPath();
      for (var dot, i = 0, n = dots.length; i < n; i++) {
        dot = dots[i];
        context.moveTo(dot.x + dot.radius, dot.y);
        context.arc(dot.x, dot.y, dot.radius, 0, Math.PI * 2);
      }
      context.globalAlpha = 1.0;
      context.fillStyle = DOT_COLOR;
      context.fill();
    }

    setup();

  </script>
</body>
</html>