Clip.js

var easingFuncs = require("./easing");

/**
 * 动画主控制器
 * @config target 动画对象，可以是数组，如果是数组的话会批量分发onframe等事件
 * @config life(1000) 动画时长
 * @config delay(0) 动画延迟时间
 * @config loop(true)
 * @config gap(0) 循环的间隔时间
 * @config onframe
 * @config easing(optional)
 * @config ondestroy(optional)
 * @config onrestart(optional)
 *
 * TODO pause
 */
function Clip(options) {
  this._target = options.target; // 生命周期

  this._life = options.life || 1000; // 延时

  this._delay = options.delay || 0; // 开始时间
  // this._startTime = new Date().getTime() + this._delay;// 单位毫秒

  this._initialized = false; // 是否循环

  this.loop = options.loop == null ? false : options.loop;
  this.gap = options.gap || 0;
  this.easing = options.easing || 'Linear';
  this.onframe = options.onframe;
  this.ondestroy = options.ondestroy;
  this.onrestart = options.onrestart;
  this._pausedTime = 0;
  this._paused = false;
}

Clip.prototype = {
  constructor: Clip,
  step: function (globalTime, deltaTime) {
    // Set startTime on first step, or _startTime may has milleseconds different between clips
    // PENDING
    if (!this._initialized) {
      this._startTime = globalTime + this._delay;
      this._initialized = true;
    }

    if (this._paused) {
      this._pausedTime += deltaTime;
      return;
    }

    var percent = (globalTime - this._startTime - this._pausedTime) / this._life; // 还没开始

    if (percent < 0) {
      return;
    }

    percent = Math.min(percent, 1);
    var easing = this.easing;
    var easingFunc = typeof easing === 'string' ? easingFuncs[easing] : easing;
    var schedule = typeof easingFunc === 'function' ? easingFunc(percent) : percent;
    this.fire('frame', schedule); // 结束

    if (percent === 1) {
      if (this.loop) {
        this.restart(globalTime); // 重新开始周期
        // 抛出而不是直接调用事件直到 stage.update 后再统一调用这些事件

        return 'restart';
      } // 动画完成将这个控制器标识为待删除
      // 在Animation.update中进行批量删除


      this._needsRemove = true;
      return 'destroy';
    }

    return null;
  },
  restart: function (globalTime) {
    var remainder = (globalTime - this._startTime - this._pausedTime) % this._life;
    this._startTime = globalTime - remainder + this.gap;
    this._pausedTime = 0;
    this._needsRemove = false;
  },
  fire: function (eventType, arg) {
    eventType = 'on' + eventType;

    if (this[eventType]) {
      this[eventType](this._target, arg);
    }
  },
  pause: function () {
    this._paused = true;
  },
  resume: function () {
    this._paused = false;
  }
};
var _default = Clip;
module.exports = _default;