73bcce88
 luigser
COMPONENTS
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
|
<!--
@license
Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->
<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
<script>
(function() {
'use strict';
/**
* The IronDropdownScrollManager is intended to provide a central source
* of authority and control over which elements in a document are currently
* allowed to scroll.
*/
Polymer.IronDropdownScrollManager = {
/**
* The current element that defines the DOM boundaries of the
* scroll lock. This is always the most recently locking element.
*/
get currentLockingElement() {
return this._lockingElements[this._lockingElements.length - 1];
},
/**
* Returns true if the provided element is "scroll locked," which is to
* say that it cannot be scrolled via pointer or keyboard interactions.
*
* @param {HTMLElement} element An HTML element instance which may or may
* not be scroll locked.
*/
elementIsScrollLocked: function(element) {
var currentLockingElement = this.currentLockingElement;
|
|
73bcce88
luigser
COMPONENTS
|
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
var scrollLocked;
if (this._hasCachedLockedElement(element)) {
return true;
}
if (this._hasCachedUnlockedElement(element)) {
return false;
}
scrollLocked = !!currentLockingElement &&
currentLockingElement !== element &&
!this._composedTreeContains(currentLockingElement, element);
if (scrollLocked) {
this._lockedElementCache.push(element);
} else {
this._unlockedElementCache.push(element);
}
return scrollLocked;
},
/**
* Push an element onto the current scroll lock stack. The most recently
* pushed element and its children will be considered scrollable. All
* other elements will not be scrollable.
*
* Scroll locking is implemented as a stack so that cases such as
* dropdowns within dropdowns are handled well.
*
* @param {HTMLElement} element The element that should lock scroll.
*/
pushScrollLock: function(element) {
if (this._lockingElements.length === 0) {
this._lockScrollInteractions();
}
this._lockingElements.push(element);
this._lockedElementCache = [];
this._unlockedElementCache = [];
},
/**
* Remove an element from the scroll lock stack. The element being
* removed does not need to be the most recently pushed element. However,
* the scroll lock constraints only change when the most recently pushed
* element is removed.
*
* @param {HTMLElement} element The element to remove from the scroll
* lock stack.
*/
removeScrollLock: function(element) {
var index = this._lockingElements.indexOf(element);
if (index === -1) {
return;
}
this._lockingElements.splice(index, 1);
this._lockedElementCache = [];
this._unlockedElementCache = [];
if (this._lockingElements.length === 0) {
this._unlockScrollInteractions();
}
},
_lockingElements: [],
_lockedElementCache: null,
_unlockedElementCache: null,
_originalBodyStyles: {},
_isScrollingKeypress: function(event) {
return Polymer.IronA11yKeysBehavior.keyboardEventMatchesKeys(
event, 'pageup pagedown home end up left down right');
},
_hasCachedLockedElement: function(element) {
return this._lockedElementCache.indexOf(element) > -1;
},
_hasCachedUnlockedElement: function(element) {
return this._unlockedElementCache.indexOf(element) > -1;
},
_composedTreeContains: function(element, child) {
// NOTE(cdata): This method iterates over content elements and their
// corresponding distributed nodes to implement a contains-like method
// that pierces through the composed tree of the ShadowDOM. Results of
// this operation are cached (elsewhere) on a per-scroll-lock basis, to
// guard against potentially expensive lookups happening repeatedly as
// a user scrolls / touchmoves.
var contentElements;
var distributedNodes;
var contentIndex;
var nodeIndex;
if (element.contains(child)) {
return true;
}
contentElements = Polymer.dom(element).querySelectorAll('content');
for (contentIndex = 0; contentIndex < contentElements.length; ++contentIndex) {
distributedNodes = Polymer.dom(contentElements[contentIndex]).getDistributedNodes();
for (nodeIndex = 0; nodeIndex < distributedNodes.length; ++nodeIndex) {
if (this._composedTreeContains(distributedNodes[nodeIndex], child)) {
return true;
}
}
}
return false;
},
_scrollInteractionHandler: function(event) {
if (Polymer
.IronDropdownScrollManager
.elementIsScrollLocked(event.target)) {
if (event.type === 'keydown' &&
!Polymer.IronDropdownScrollManager._isScrollingKeypress(event)) {
return;
}
event.preventDefault();
}
},
_lockScrollInteractions: function() {
// Memoize body inline styles:
this._originalBodyStyles.overflow = document.body.style.overflow;
this._originalBodyStyles.overflowX = document.body.style.overflowX;
this._originalBodyStyles.overflowY = document.body.style.overflowY;
// Disable overflow scrolling on body:
// TODO(cdata): It is technically not sufficient to hide overflow on
// body alone. A better solution might be to traverse all ancestors of
// the current scroll locking element and hide overflow on them. This
// becomes expensive, though, as it would have to be redone every time
// a new scroll locking element is added.
document.body.style.overflow = 'hidden';
document.body.style.overflowX = 'hidden';
document.body.style.overflowY = 'hidden';
// Modern `wheel` event for mouse wheel scrolling:
window.addEventListener('wheel', this._scrollInteractionHandler, true);
// Older, non-standard `mousewheel` event for some FF:
window.addEventListener('mousewheel', this._scrollInteractionHandler, true);
// IE:
window.addEventListener('DOMMouseScroll', this._scrollInteractionHandler, true);
// Mobile devices can scroll on touch move:
window.addEventListener('touchmove', this._scrollInteractionHandler, true);
// Capture keydown to prevent scrolling keys (pageup, pagedown etc.)
document.addEventListener('keydown', this._scrollInteractionHandler, true);
},
_unlockScrollInteractions: function() {
document.body.style.overflow = this._originalBodyStyles.overflow;
document.body.style.overflowX = this._originalBodyStyles.overflowX;
document.body.style.overflowY = this._originalBodyStyles.overflowY;
window.removeEventListener('wheel', this._scrollInteractionHandler, true);
window.removeEventListener('mousewheel', this._scrollInteractionHandler, true);
window.removeEventListener('DOMMouseScroll', this._scrollInteractionHandler, true);
window.removeEventListener('touchmove', this._scrollInteractionHandler, true);
document.removeEventListener('keydown', this._scrollInteractionHandler, true);
}
};
})();
</script>
|
graphs updates