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1 <!-- | |
2 @license | |
3 Copyright (c) 2015 The Polymer Project Authors. All rights reserved. | |
4 This code may only be used under the BSD style license found at http://polymer.g
ithub.io/LICENSE.txt | |
5 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt | |
6 The complete set of contributors may be found at http://polymer.github.io/CONTRI
BUTORS.txt | |
7 Code distributed by Google as part of the polymer project is also | |
8 subject to an additional IP rights grant found at http://polymer.github.io/PATEN
TS.txt | |
9 --> | |
10 | |
11 <link rel="import" href="../polymer/polymer.html"> | |
12 <link rel="import" href="../iron-resizable-behavior/iron-resizable-behavior.html
"> | |
13 | |
14 <!-- | |
15 `paper-scroll-header-panel` contains a header section and a content section. Th
e | |
16 header is initially on the top part of the view but it scrolls away with the | |
17 rest of the scrollable content. Upon scrolling slightly up at any point, the | |
18 header scrolls back into view. This saves screen space and allows users to | |
19 access important controls by easily moving them back to the view. | |
20 | |
21 __Important:__ The `paper-scroll-header-panel` will not display if its parent do
es not have a height. | |
22 | |
23 Using [layout attributes](http://www.polymer-project.org/docs/polymer/layout-att
rs.html), you can easily make the `paper-scroll-header-panel` fill the screen | |
24 | |
25 <body class="fullbleed layout vertical"> | |
26 <paper-scroll-header-panel class="flex"> | |
27 <paper-toolbar> | |
28 <div>Hello World!</div> | |
29 </paper-toolbar> | |
30 </paper-scroll-header-panel> | |
31 </body> | |
32 | |
33 or, if you would prefer to do it in CSS, just give `html`, `body`, and `paper-sc
roll-header-panel` a height of 100%: | |
34 | |
35 html, body { | |
36 height: 100%; | |
37 margin: 0; | |
38 } | |
39 paper-scroll-header-panel { | |
40 height: 100%; | |
41 } | |
42 | |
43 `paper-scroll-header-panel` works well with `paper-toolbar` but can use any elem
ent | |
44 that represents a header by adding a `core-header` class to it. | |
45 | |
46 <paper-scroll-header-panel> | |
47 <paper-toolbar>Header</paper-toolbar> | |
48 <div>Content goes here...</div> | |
49 </paper-scroll-header-panel> | |
50 | |
51 Styling scroll-header-panel: | |
52 | |
53 To change background for toolbar when it is at its full size: | |
54 | |
55 paper-scroll-header-panel { | |
56 --paper-scroll-header-panel-full-header: { | |
57 background-color: red; | |
58 }; | |
59 } | |
60 | |
61 To change the background for toolbar when it is condensed: | |
62 | |
63 paper-scroll-header-panel { | |
64 --paper-scroll-header-panel-condensed-header: { | |
65 background-color: #f4b400; | |
66 }; | |
67 } | |
68 | |
69 @group Paper Element | |
70 @element paper-scrollheader-panel | |
71 @demo demo/index.html | |
72 @hero hero.svg | |
73 --> | |
74 | |
75 <dom-module id="paper-scroll-header-panel"> | |
76 | |
77 <style> | |
78 :host { | |
79 display: block; | |
80 position: relative; | |
81 overflow: hidden; | |
82 } | |
83 | |
84 #mainContainer { | |
85 position: absolute; | |
86 top: 0; | |
87 right: 0; | |
88 bottom: 0; | |
89 left: 0; | |
90 box-sizing: border-box; | |
91 -moz-box-sizing: border-box; | |
92 -webkit-overflow-scrolling: touch; | |
93 overflow-x: hidden; | |
94 overflow-_y: auto; | |
95 -webkit-transform: translateZ(0); | |
96 transform: translateZ(0); | |
97 } | |
98 | |
99 #headerContainer { | |
100 position: absolute; | |
101 top: 0; | |
102 right: 0; | |
103 left: 0; | |
104 } | |
105 | |
106 .bg-container { | |
107 position: absolute; | |
108 top: 0; | |
109 left: 0; | |
110 width: 100%; | |
111 height: 100%; | |
112 overflow: hidden; | |
113 } | |
114 | |
115 #headerBg { | |
116 @apply(--paper-scroll-header-panel-full-header); | |
117 } | |
118 | |
119 #condensedHeaderBg { | |
120 @apply(--paper-scroll-header-panel-condensed-header); | |
121 } | |
122 | |
123 #headerBg, #condensedHeaderBg { | |
124 position: absolute; | |
125 top: 0; | |
126 left: 0; | |
127 width: 100%; | |
128 height: 100%; | |
129 background-repeat: no-repeat; | |
130 background-size: cover; | |
131 background-position: center center; | |
132 } | |
133 | |
134 #condensedHeaderBg { | |
135 opacity: 0; | |
136 } | |
137 </style> | |
138 <template> | |
139 <div id="mainContainer"> | |
140 <content id="mainContent" select=":not(paper-toolbar):not(.paper-header)">
</content> | |
141 </div> | |
142 <div id="headerContainer"> | |
143 <div class="bg-container"> | |
144 <div id="condensedHeaderBg"></div> | |
145 <div id="headerBg"></div> | |
146 </div> | |
147 <content id="headerContent" select="paper-toolbar, .paper-header"></conten
t> | |
148 </div> | |
149 </template> | |
150 </dom-module> | |
151 | |
152 <script> | |
153 (function() { | |
154 | |
155 'use strict'; | |
156 | |
157 Polymer({ | |
158 | |
159 /** | |
160 * Fired when the content has been scrolled. | |
161 * | |
162 * @event content-scroll | |
163 */ | |
164 | |
165 /** | |
166 * Fired when the header is transformed. | |
167 * | |
168 * @event paper-header-transform | |
169 */ | |
170 | |
171 is: 'paper-scroll-header-panel', | |
172 | |
173 behaviors: [ | |
174 Polymer.IronResizableBehavior | |
175 ], | |
176 | |
177 properties: { | |
178 | |
179 /** | |
180 * If true, the header's height will condense to `_condensedHeaderHeight` | |
181 * as the user scrolls down from the top of the content area. | |
182 */ | |
183 condenses: { | |
184 type: Boolean, | |
185 value: false, | |
186 observer: '_condensesChanged' | |
187 }, | |
188 | |
189 /** | |
190 * If true, no cross-fade transition from one background to another. | |
191 */ | |
192 noDissolve: { | |
193 type: Boolean, | |
194 value: false | |
195 }, | |
196 | |
197 /** | |
198 * If true, the header doesn't slide back in when scrolling back up. | |
199 */ | |
200 noReveal: { | |
201 type: Boolean, | |
202 value: false | |
203 }, | |
204 | |
205 /** | |
206 * If true, the header is fixed to the top and never moves away. | |
207 */ | |
208 fixed: { | |
209 type: Boolean, | |
210 value: false | |
211 }, | |
212 | |
213 /** | |
214 * If true, the condensed header is always shown and does not move away. | |
215 */ | |
216 keepCondensedHeader: { | |
217 type: Boolean, | |
218 value: false | |
219 }, | |
220 | |
221 /** | |
222 * The height of the header when it is at its full size. | |
223 * | |
224 * By default, the height will be measured when it is ready. If the heigh
t | |
225 * changes later the user needs to either set this value to reflect the | |
226 * new height or invoke `measureHeaderHeight()`. | |
227 */ | |
228 headerHeight: { | |
229 type: Number, | |
230 value: 0 | |
231 }, | |
232 | |
233 /** | |
234 * The height of the header when it is condensed. | |
235 * | |
236 * By default, `_condensedHeaderHeight` is 1/3 of `headerHeight` unless | |
237 * this is specified. | |
238 */ | |
239 condensedHeaderHeight: { | |
240 type: Number, | |
241 value: 0 | |
242 }, | |
243 | |
244 /** | |
245 * By default, the top part of the header stays when the header is being | |
246 * condensed. Set this to true if you want the top part of the header | |
247 * to be scrolled away. | |
248 */ | |
249 scrollAwayTopbar: { | |
250 type: Boolean, | |
251 value: false | |
252 }, | |
253 | |
254 _headerMargin: { | |
255 type: Number | |
256 }, | |
257 | |
258 _prevScrollTop: { | |
259 type: Number | |
260 }, | |
261 | |
262 _y: { | |
263 type: Number | |
264 } | |
265 | |
266 }, | |
267 | |
268 observers: [ | |
269 '_setup(_headerMargin, headerHeight, fixed)', | |
270 '_headerHeightChanged(headerHeight, condensedHeaderHeight)', | |
271 '_condensedHeaderHeightChanged(headerHeight, condensedHeaderHeight)' | |
272 ], | |
273 | |
274 listeners: { | |
275 'iron-resize': 'measureHeaderHeight' | |
276 }, | |
277 | |
278 ready: function() { | |
279 this.async(this.measureHeaderHeight, 5); | |
280 this._scrollHandler = this._scroll.bind(this); | |
281 this.scroller.addEventListener('scroll', this._scrollHandler); | |
282 }, | |
283 | |
284 detached: function() { | |
285 this.scroller.removeEventListener('scroll', this._scrollHandler); | |
286 }, | |
287 | |
288 /** | |
289 * Returns the header element. | |
290 * | |
291 * @property header | |
292 * @type Object | |
293 */ | |
294 get header() { | |
295 return Polymer.dom(this.$.headerContent).getDistributedNodes()[0]; | |
296 }, | |
297 | |
298 /** | |
299 * Returns the content element. | |
300 * | |
301 * @property content | |
302 * @type Object | |
303 */ | |
304 get content() { | |
305 return Polymer.dom(this.$.mainContent).getDistributedNodes()[0]; | |
306 }, | |
307 | |
308 /** | |
309 * Returns the scrollable element. | |
310 * | |
311 * @property scroller | |
312 * @type Object | |
313 */ | |
314 get scroller() { | |
315 return this.$.mainContainer; | |
316 }, | |
317 | |
318 /** | |
319 * Invoke this to tell `paper-scroll-header-panel` to re-measure the header'
s | |
320 * height. | |
321 * | |
322 * @method measureHeaderHeight | |
323 */ | |
324 measureHeaderHeight: function() { | |
325 var header = this.header; | |
326 if (header && header.offsetHeight) { | |
327 this.headerHeight = header.offsetHeight; | |
328 } | |
329 }, | |
330 | |
331 _headerHeightChanged: function() { | |
332 if (!this.condensedHeaderHeight) { | |
333 // assume condensedHeaderHeight is 1/3 of the headerHeight | |
334 this.condensedHeaderHeight = this.headerHeight * 1 / 3; | |
335 } | |
336 }, | |
337 | |
338 _condensedHeaderHeightChanged: function() { | |
339 if (this.headerHeight) { | |
340 this._headerMargin = this.headerHeight - this.condensedHeaderHeight; | |
341 } | |
342 }, | |
343 | |
344 _condensesChanged: function() { | |
345 if (this.condenses) { | |
346 this._scroll(); | |
347 } else { | |
348 // reset transform/opacity set on the header | |
349 this._condenseHeader(null); | |
350 } | |
351 }, | |
352 | |
353 _setup: function() { | |
354 var s = this.scroller.style; | |
355 s.paddingTop = this.fixed ? '' : this.headerHeight + 'px'; | |
356 | |
357 s.top = this.fixed ? this.headerHeight + 'px' : ''; | |
358 | |
359 if (this.fixed) { | |
360 this._transformHeader(null); | |
361 } else { | |
362 this._scroll(); | |
363 } | |
364 }, | |
365 | |
366 _transformHeader: function(y) { | |
367 var s = this.$.headerContainer.style; | |
368 this._translateY(s, -y); | |
369 | |
370 if (this.condenses) { | |
371 this._condenseHeader(y); | |
372 } | |
373 | |
374 this.fire('paper-header-transform', {y: y, height: this.headerHeight, | |
375 condensedHeight: this.condensedHeaderHeight}); | |
376 }, | |
377 | |
378 _condenseHeader: function(y) { | |
379 var reset = (y === null); | |
380 | |
381 // adjust top bar in core-header so the top bar stays at the top | |
382 if (!this.scrollAwayTopbar && this.header.$ && this.header.$.topBar) { | |
383 this._translateY(this.header.$.topBar.style, | |
384 reset ? null : Math.min(y, this._headerMargin)); | |
385 } | |
386 // transition header bg | |
387 var hbg = this.$.headerBg.style; | |
388 if (!this.noDissolve) { | |
389 hbg.opacity = reset ? '' : (this._headerMargin - y) / this._headerMargin
; | |
390 } | |
391 // adjust header bg so it stays at the center | |
392 this._translateY(hbg, reset ? null : y / 2); | |
393 // transition condensed header bg | |
394 if (!this.noDissolve) { | |
395 var chbg = this.$.condensedHeaderBg.style; | |
396 chbg = this.$.condensedHeaderBg.style; | |
397 chbg.opacity = reset ? '' : y / this._headerMargin; | |
398 | |
399 // adjust condensed header bg so it stays at the center | |
400 this._translateY(chbg, reset ? null : y / 2); | |
401 } | |
402 }, | |
403 | |
404 _translateY: function(s, y) { | |
405 var t = (y === null) ? '' : 'translate3d(0, ' + y + 'px, 0)'; | |
406 setTransform(s, t); | |
407 }, | |
408 | |
409 _scroll: function(event) { | |
410 if (!this.header) { | |
411 return; | |
412 } | |
413 | |
414 var sTop = this.scroller.scrollTop; | |
415 | |
416 this._y = this._y || 0; | |
417 this._prevScrollTop = this._prevScrollTop || 0; | |
418 | |
419 var y = Math.min(this.keepCondensedHeader ? | |
420 this._headerMargin : this.headerHeight, Math.max(0, | |
421 (this.noReveal ? sTop : this._y + sTop - this._prevScrollTop))); | |
422 | |
423 if (this.condenses && this._prevScrollTop >= sTop && sTop > this._headerMa
rgin) { | |
424 y = Math.max(y, this._headerMargin); | |
425 } | |
426 | |
427 if (!event || !this.fixed && y !== this._y) { | |
428 this._transformHeader(y); | |
429 } | |
430 | |
431 this._prevScrollTop = Math.max(sTop, 0); | |
432 this._y = y; | |
433 | |
434 if (event) { | |
435 this.fire('content-scroll', {target: this.scroller}, this, false); | |
436 } | |
437 } | |
438 | |
439 }); | |
440 | |
441 //determine proper transform mechanizm | |
442 if (document.documentElement.style.transform !== undefined) { | |
443 var setTransform = function(style, string) { | |
444 style.transform = string; | |
445 } | |
446 } else { | |
447 var setTransform = function(style, string) { | |
448 style.webkitTransform = string; | |
449 } | |
450 } | |
451 | |
452 })(); | |
453 | |
454 </script> | |
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