chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-button.js

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

Polymer({
  is: 'viewer-zoom-button',

  properties: {
    /**
     * Icons to be displayed on the FAB. Multiple icons should be separated with
     * spaces, and will be cycled through every time the FAB is clicked.
     */
    icons: String,

    /**
     * Array version of the list of icons. Polymer does not allow array
     * properties to be set from HTML, so we must use a string property and
     * perform the conversion manually.
     * @private
     */
    icons_: {
      type: Array,
      value: [''],
      computed: 'computeIconsArray_(icons)'
    },

    tooltips: Array,

    closed: {
      type: Boolean,
      reflectToAttribute: true,
      value: false
    },

    delay: {
      type: Number,
      observer: 'delayChanged_'
    },

    /**
     * Index of the icon currently being displayed.
     */
    activeIndex: {
      type: Number,
      value: 0
    },

    /**
     * Icon currently being displayed on the FAB.
     * @private
     */
    visibleIcon_: {
      type: String,
      computed: 'computeVisibleIcon_(icons_, activeIndex)'
    },

    visibleTooltip_: {
      type: String,
      computed: 'computeVisibleTooltip_(tooltips, activeIndex)'
    }
  },

  computeIconsArray_: function(icons) {
    return icons.split(' ');
  },

  computeVisibleIcon_: function(icons, activeIndex) {
    return icons[activeIndex];
  },

  computeVisibleTooltip_: function(tooltips, activeIndex) {
    return tooltips[activeIndex];
  },

  delayChanged_: function() {
    this.$.wrapper.style.transitionDelay = this.delay + 'ms';
  },

  show: function() {
    this.closed = false;
  },

  hide: function() {
    this.closed = true;
  },

  fireClick: function() {
    // We cannot attach an on-click to the entire viewer-zoom-button, as this
    // will include clicks on the margins. Instead, proxy clicks on the FAB
    // through.
    this.fire('fabclick');

    this.activeIndex = (this.activeIndex + 1) % this.icons_.length;
  }
});