sky/framework/animation/controller.sky

<!--
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
-->
<import src="timer.sky" as="AnimationTimer" />
<script>
module.exports = class AnimationController {
  constructor(delegate) {
    this.delegate_ = delegate;
    this.timer_ = new AnimationTimer(this);
    this.begin_ = 0;
    this.end_ = 0;
    this.curve_ = null;
    this.isAnimating = false;
    Object.preventExtensions(this);
  }

  start(options) {
    this.begin_ = options.begin;
    this.end_ = options.end;
    this.curve_ = options.curve;
    this.isAnimating = true;
    this.timer_.start(options.duration);
  }

  stop() {
    this.isAnimating = false;
    this.timer_.stop();
  }

  positionForTime_(t) {
    // Explicitly finish animations at |this.end_| in case the curve isn't an
    // exact numerical transform.
    if (t == 1)
      return this.end_;
    var curvedTime = this.curve_.transform(t);
    var begin = this.begin_;
    return begin + (this.end_ - begin) * curvedTime;
  }

  updateAnimation(t) {
    this.delegate_.updateAnimation(this.positionForTime_(t));
  }
};
</script>