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// Copyright 2014 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-page-indicator',
properties: {
label: {type: String, value: '1'},
index: {type: Number, observer: 'indexChanged'},
pageLabels: {type: Array, value: null, observer: 'pageLabelsChanged'}
},
/** @type {number|undefined} */
timerId: undefined,
/** @override */
ready: function() {
const callback = this.fadeIn_.bind(this);
window.addEventListener('scroll', function() {
requestAnimationFrame(callback);
});
},
/** @private */
fadeIn_: function() {
const percent = window.scrollY /
(document.scrollingElement.scrollHeight -
document.documentElement.clientHeight);
this.style.top =
percent * (document.documentElement.clientHeight - this.offsetHeight) +
'px';
// <if expr="is_macosx">
// If overlay scrollbars are enabled, prevent them from overlapping the
// triangle. TODO(dbeam): various platforms can enable overlay scrolling,
// not just Mac. The scrollbars seem to have different widths/appearances on
// those platforms, though.
assert(document.documentElement.dir);
const endEdge = isRTL() ? 'left' : 'right';
if (window.innerWidth == document.scrollingElement.scrollWidth) {
this.style[endEdge] = '16px';
} else {
this.style[endEdge] = '0px';
}
// </if>
this.style.opacity = 1;
clearTimeout(this.timerId);
this.timerId = setTimeout(() => {
this.style.opacity = 0;
this.timerId = undefined;
}, 2000);
},
pageLabelsChanged: function() {
this.indexChanged();
},
indexChanged: function() {
if (this.pageLabels) {
this.label = this.pageLabels[this.index];
} else {
this.label = String(this.index + 1);
}
}
});
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