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({
   6   is: 'viewer-page-indicator',
   7
   8   properties: {
   9     label: {
  10       type: String,
  11       value: '1'
  12     },
  13
  14     index: {
  15       type: Number,
  16       observer: 'indexChanged'
  17     },
  18
  19     pageLabels: {
  20       type: Array,
  21       value: null,
  22       observer: 'pageLabelsChanged'
  23     }
  24   },
  25
  26   timerId: undefined,
  27
  28   ready: function() {
  29     var callback = this.fadeIn.bind(this, 2000);
  30     window.addEventListener('scroll', function() {
  31       requestAnimationFrame(callback);
  32     });
  33   },
  34
  35   initialFadeIn: function() {
  36     this.fadeIn(6000);
  37   },
  38
  39   fadeIn: function(displayTime) {
  40     var percent = window.scrollY /
  41         (document.body.scrollHeight -
  42          document.documentElement.clientHeight);
  43     this.style.top = percent *
  44         (document.documentElement.clientHeight - this.offsetHeight) + 'px';
  45     this.style.opacity = 1;
  46     clearTimeout(this.timerId);
  47
  48     this.timerId = setTimeout(function() {
  49       this.style.opacity = 0;
  50       this.timerId = undefined;
  51     }.bind(this), displayTime);
  52   },
  53
  54   pageLabelsChanged: function() {
  55     this.indexChanged();
  56   },
  57
  58   indexChanged: function() {
  59     if (this.pageLabels)
  60       this.label = this.pageLabels[this.index];
  61     else
  62       this.label = String(this.index + 1);
  63   }
  64 });