text: class CameraZoomControl {
    constructor (constraints) {
      constraints = constraints || {};
      this._c = constraints;
  
      constraints.min = constraints.min || 0.1;
      constraints.max = constraints.max || 1000;
    }
  
    setValue (time, value) {
      this._nextValue = Math.min(Math.max(value, this._c.min), this._c.max);
      this._updateRequired = !this._value || this._value !== this._nextValue;
    }
  
    getValue () {
      return this._value;
    }
  
    get updateRequired () {
      return this._updateRequired;
    }
  
    preRender () {
      this._value = this._nextValue;
      this._updateRequired = false;
      return true;
    }
  }
  
  export {
    CameraZoomControl
  };
  