Method animateFixedElements

src/service/fixed-layer.js:884–904

* @param {number} paddingTop * @param {number} lastPaddingTop * @param {number} duration * @param {string} curve * @param {boolean} transient * @return {!Promise}

(paddingTop, lastPaddingTop, duration, curve, transient)

   * @return {!Promise}
   */
  animateFixedElements(paddingTop, lastPaddingTop, duration, curve, transient) {
    this.updatePaddingTop(paddingTop, transient);
    if (duration <= 0) {
      return Promise.resolve();
    }
    // Add transit effect on position fixed element
    const tr = (time) => {
      return lastPaddingTop - paddingTop + (paddingTop - lastPaddingTop) * time;
    };
    return Animation.animate(
      this.ampdoc.getRootNode(),
      (time) => {
        const p = tr(time);
        this.transformMutate(`translateY(${p}px)`);
      },
      duration,
      curve
    ).thenAlways(() => {
      this.transformMutate(null);
    });
  }
}

/**