chrome/browser/resources/pdf/elements/viewer-page-indicator/viewer-page-indicator.js

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 Polymer('viewer-page-indicator', {
   6   label: '1',
   7   index: 0,
   8   timerId: undefined,
   9   pageLabels: null,
  10   ready: function() {
  11     var callback = this.fadeIn.bind(this, 2000);
  12     window.addEventListener('scroll', function() {
  13       requestAnimationFrame(callback);
  14     });
  15   },
  16   initialFadeIn: function() {
  17     this.fadeIn(6000);
  18   },
  19   fadeIn: function(displayTime) {
  20     var percent = window.scrollY /
  21         (document.body.scrollHeight -
  22          document.documentElement.clientHeight);
  23     this.style.top = percent *
  24         (document.documentElement.clientHeight - this.offsetHeight) + 'px';
  25     this.style.opacity = 1;
  26     clearTimeout(this.timerId);
  27
  28     this.timerId = setTimeout(function() {
  29       this.style.opacity = 0;
  30       this.timerId = undefined;
  31     }.bind(this), displayTime);
  32   },
  33   pageLabelsChanged: function() {
  34     this.indexChanged();
  35   },
  36   indexChanged: function() {
  37     if (this.pageLabels)
  38       this.label = this.pageLabels[this.index];
  39     else
  40       this.label = String(this.index + 1);
  41   }
  42 });