electron/atom/browser/resources/pdf_viewer/elements/viewer-toolbar-dropdown/viewer-toolbar-dropdown.js
2017-03-14 00:25:59 +05:30

138 lines
4 KiB
JavaScript

// 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.
(function() {
/**
* Size of additional padding in the inner scrollable section of the dropdown.
*/
var DROPDOWN_INNER_PADDING = 12;
/** Size of vertical padding on the outer #dropdown element. */
var DROPDOWN_OUTER_PADDING = 2;
/** Minimum height of toolbar dropdowns (px). */
var MIN_DROPDOWN_HEIGHT = 200;
Polymer({
is: 'viewer-toolbar-dropdown',
properties: {
/** String to be displayed at the top of the dropdown. */
header: String,
/** Icon to display when the dropdown is closed. */
closedIcon: String,
/** Icon to display when the dropdown is open. */
openIcon: String,
/** True if the dropdown is currently open. */
dropdownOpen: {
type: Boolean,
reflectToAttribute: true,
value: false
},
/** Toolbar icon currently being displayed. */
dropdownIcon: {
type: String,
computed: 'computeIcon_(dropdownOpen, closedIcon, openIcon)'
},
/** Lowest vertical point that the dropdown should occupy (px). */
lowerBound: {
type: Number,
observer: 'lowerBoundChanged_'
},
/**
* True if the max-height CSS property for the dropdown scroll container
* is valid. If false, the height will be updated the next time the
* dropdown is visible.
*/
maxHeightValid_: false,
/** Current animation being played, or null if there is none. */
animation_: Object
},
computeIcon_: function(dropdownOpen, closedIcon, openIcon) {
return dropdownOpen ? openIcon : closedIcon;
},
lowerBoundChanged_: function() {
this.maxHeightValid_ = false;
if (this.dropdownOpen)
this.updateMaxHeight();
},
toggleDropdown: function() {
this.dropdownOpen = !this.dropdownOpen;
if (this.dropdownOpen) {
this.$.dropdown.style.display = 'block';
if (!this.maxHeightValid_)
this.updateMaxHeight();
}
this.cancelAnimation_();
this.playAnimation_(this.dropdownOpen);
},
updateMaxHeight: function() {
var scrollContainer = this.$['scroll-container'];
var height = this.lowerBound -
scrollContainer.getBoundingClientRect().top -
DROPDOWN_INNER_PADDING;
height = Math.max(height, MIN_DROPDOWN_HEIGHT);
scrollContainer.style.maxHeight = height + 'px';
this.maxHeightValid_ = true;
},
cancelAnimation_: function() {
if (this._animation)
this._animation.cancel();
},
/**
* Start an animation on the dropdown.
* @param {boolean} isEntry True to play entry animation, false to play
* exit.
* @private
*/
playAnimation_: function(isEntry) {
this.animation_ = isEntry ? this.animateEntry_() : this.animateExit_();
this.animation_.onfinish = function() {
this.animation_ = null;
if (!this.dropdownOpen)
this.$.dropdown.style.display = 'none';
}.bind(this);
},
animateEntry_: function() {
var maxHeight = this.$.dropdown.getBoundingClientRect().height -
DROPDOWN_OUTER_PADDING;
if (maxHeight < 0)
maxHeight = 0;
var fade = new KeyframeEffect(this.$.dropdown, [
{opacity: 0},
{opacity: 1}
], {duration: 150, easing: 'cubic-bezier(0, 0, 0.2, 1)'});
var slide = new KeyframeEffect(this.$.dropdown, [
{height: '20px', transform: 'translateY(-10px)'},
{height: maxHeight + 'px', transform: 'translateY(0)'}
], {duration: 250, easing: 'cubic-bezier(0, 0, 0.2, 1)'});
return document.timeline.play(new GroupEffect([fade, slide]));
},
animateExit_: function() {
return this.$.dropdown.animate([
{transform: 'translateY(0)', opacity: 1},
{transform: 'translateY(-5px)', opacity: 0}
], {duration: 100, easing: 'cubic-bezier(0.4, 0, 1, 1)'});
}
});
})();