summaryrefslogblamecommitdiffstats
path: root/talks/cowboy-2/README.md
blob: 3068c03855ba8368ef6dfa391dfec0bdc5a5fb3f (plain) (tree)
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
44
45
46
47
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
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050

























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
# reveal.js [![Build Status](https://travis-ci.org/hakimel/reveal.js.svg?branch=master)](https://travis-ci.org/hakimel/reveal.js)

A framework for easily creating beautiful presentations using HTML. [Check out the live demo](http://lab.hakim.se/reveal-js/).

reveal.js comes with a broad range of features including [nested slides](https://github.com/hakimel/reveal.js#markup), [Markdown contents](https://github.com/hakimel/reveal.js#markdown), [PDF export](https://github.com/hakimel/reveal.js#pdf-export), [speaker notes](https://github.com/hakimel/reveal.js#speaker-notes) and a [JavaScript API](https://github.com/hakimel/reveal.js#api). It's best viewed in a modern browser but [fallbacks](https://github.com/hakimel/reveal.js/wiki/Browser-Support) are available to make sure your presentation can still be viewed elsewhere.


#### More reading:
- [Installation](#installation): Step-by-step instructions for getting reveal.js running on your computer.
- [Changelog](https://github.com/hakimel/reveal.js/releases): Up-to-date version history.
- [Examples](https://github.com/hakimel/reveal.js/wiki/Example-Presentations): Presentations created with reveal.js, add your own!
- [Browser Support](https://github.com/hakimel/reveal.js/wiki/Browser-Support): Explanation of browser support and fallbacks.
- [Plugins](https://github.com/hakimel/reveal.js/wiki/Plugins,-Tools-and-Hardware): A list of plugins that can be used to extend reveal.js.

## Online Editor

Presentations are written using HTML or Markdown but there's also an online editor for those of you who prefer a graphical interface. Give it a try at [http://slides.com](http://slides.com).


## Instructions

### Markup

Markup hierarchy needs to be ``<div class="reveal"> <div class="slides"> <section>`` where the ``<section>`` represents one slide and can be repeated indefinitely. If you place multiple ``<section>``'s inside of another ``<section>`` they will be shown as vertical slides. The first of the vertical slides is the "root" of the others (at the top), and it will be included in the horizontal sequence. For example:

```html
<div class="reveal">
	<div class="slides">
		<section>Single Horizontal Slide</section>
		<section>
			<section>Vertical Slide 1</section>
			<section>Vertical Slide 2</section>
		</section>
	</div>
</div>
```

### Markdown

It's possible to write your slides using Markdown. To enable Markdown, add the ```data-markdown``` attribute to your ```<section>``` elements and wrap the contents in a ```<script type="text/template">``` like the example below.

This is based on [data-markdown](https://gist.github.com/1343518) from [Paul Irish](https://github.com/paulirish) modified to use [marked](https://github.com/chjj/marked) to support [Github Flavoured Markdown](https://help.github.com/articles/github-flavored-markdown). Sensitive to indentation (avoid mixing tabs and spaces) and line breaks (avoid consecutive breaks).

```html
<section data-markdown>
	<script type="text/template">
		## Page title

		A paragraph with some text and a [link](http://hakim.se).
	</script>
</section>
```

#### External Markdown

You can write your content as a separate file and have reveal.js load it at runtime. Note the separator arguments which determine how slides are delimited in the external file. The ```data-charset``` attribute is optional and specifies which charset to use when loading the external file.

When used locally, this feature requires that reveal.js [runs from a local web server](#full-setup).

```html
<section data-markdown="example.md"  
         data-separator="^\n\n\n"  
         data-separator-vertical="^\n\n"  
         data-separator-notes="^Note:"  
         data-charset="iso-8859-15">
</section>
```

#### Element Attributes

Special syntax (in html comment) is available for adding attributes to Markdown elements. This is useful for fragments, amongst other things.

```html
<section data-markdown>
	<script type="text/template">
		- Item 1 <!-- .element: class="fragment" data-fragment-index="2" -->
		- Item 2 <!-- .element: class="fragment" data-fragment-index="1" -->
	</script>
</section>
```

#### Slide Attributes

Special syntax (in html comment) is available for adding attributes to the slide `<section>` elements generated by your Markdown.

```html
<section data-markdown>
	<script type="text/template">
	<!-- .slide: data-background="#ff0000" -->
		Markdown content
	</script>
</section>
```


### Configuration

At the end of your page you need to initialize reveal by running the following code. Note that all config values are optional and will default as specified below.

```javascript
Reveal.initialize({

	// Display controls in the bottom right corner
	controls: true,

	// Display a presentation progress bar
	progress: true,

	// Display the page number of the current slide
	slideNumber: false,

	// Push each slide change to the browser history
	history: false,

	// Enable keyboard shortcuts for navigation
	keyboard: true,

	// Enable the slide overview mode
	overview: true,

	// Vertical centering of slides
	center: true,

	// Enables touch navigation on devices with touch input
	touch: true,

	// Loop the presentation
	loop: false,

	// Change the presentation direction to be RTL
	rtl: false,

	// Turns fragments on and off globally
	fragments: true,

	// Flags if the presentation is running in an embedded mode,
	// i.e. contained within a limited portion of the screen
	embedded: false,

	// Flags if we should show a help overlay when the questionmark
	// key is pressed
	help: true,

	// Number of milliseconds between automatically proceeding to the
	// next slide, disabled when set to 0, this value can be overwritten
	// by using a data-autoslide attribute on your slides
	autoSlide: 0,

	// Stop auto-sliding after user input
	autoSlideStoppable: true,

	// Enable slide navigation via mouse wheel
	mouseWheel: false,

	// Hides the address bar on mobile devices
	hideAddressBar: true,

	// Opens links in an iframe preview overlay
	previewLinks: false,

	// Transition style
	transition: 'default', // none/fade/slide/convex/concave/zoom

	// Transition speed
	transitionSpeed: 'default', // default/fast/slow

	// Transition style for full page slide backgrounds
	backgroundTransition: 'default', // none/fade/slide/convex/concave/zoom

	// Number of slides away from the current that are visible
	viewDistance: 3,

	// Parallax background image
	parallaxBackgroundImage: '', // e.g. "'https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg'"

	// Parallax background size
	parallaxBackgroundSize: '' // CSS syntax, e.g. "2100px 900px"

	// Amount to move parallax background (horizontal and vertical) on slide change
	// Number, e.g. 100
	parallaxBackgroundHorizontal: '',
	parallaxBackgroundVertical: ''

});
```


The configuration can be updated after initialization using the ```configure``` method:

```javascript
// Turn autoSlide off
Reveal.configure({ autoSlide: 0 });

// Start auto-sliding every 5s
Reveal.configure({ autoSlide: 5000 });
```


### Dependencies

Reveal.js doesn't _rely_ on any third party scripts to work but a few optional libraries are included by default. These libraries are loaded as dependencies in the order they appear, for example:

```javascript
Reveal.initialize({
	dependencies: [
		// Cross-browser shim that fully implements classList - https://github.com/eligrey/classList.js/
		{ src: 'lib/js/classList.js', condition: function() { return !document.body.classList; } },

		// Interpret Markdown in <section> elements
		{ src: 'plugin/markdown/marked.js', condition: function() { return !!document.querySelector( '[data-markdown]' ); } },
		{ src: 'plugin/markdown/markdown.js', condition: function() { return !!document.querySelector( '[data-markdown]' ); } },

		// Syntax highlight for <code> elements
		{ src: 'plugin/highlight/highlight.js', async: true, callback: function() { hljs.initHighlightingOnLoad(); } },

		// Zoom in and out with Alt+click
		{ src: 'plugin/zoom-js/zoom.js', async: true },

		// Speaker notes
		{ src: 'plugin/notes/notes.js', async: true },

		// Remote control your reveal.js presentation using a touch device
		{ src: 'plugin/remotes/remotes.js', async: true },

		// MathJax
		{ src: 'plugin/math/math.js', async: true }
	]
});
```

You can add your own extensions using the same syntax. The following properties are available for each dependency object:
- **src**: Path to the script to load
- **async**: [optional] Flags if the script should load after reveal.js has started, defaults to false
- **callback**: [optional] Function to execute when the script has loaded
- **condition**: [optional] Function which must return true for the script to be loaded


### Ready Event

A 'ready' event is fired when reveal.js has loaded all non-async dependencies and is ready to start navigating. To check if reveal.js is already 'ready' you can call `Reveal.isReady()`.

```javascript
Reveal.addEventListener( 'ready', function( event ) {
	// event.currentSlide, event.indexh, event.indexv
} );
```


### Presentation Size

All presentations have a normal size, that is the resolution at which they are authored. The framework will automatically scale presentations uniformly based on this size to ensure that everything fits on any given display or viewport.

See below for a list of configuration options related to sizing, including default values:

```javascript
Reveal.initialize({

	...

	// The "normal" size of the presentation, aspect ratio will be preserved
	// when the presentation is scaled to fit different resolutions. Can be
	// specified using percentage units.
	width: 960,
	height: 700,

	// Factor of the display size that should remain empty around the content
	margin: 0.1,

	// Bounds for smallest/largest possible scale to apply to content
	minScale: 0.2,
	maxScale: 1.5

});
```


### Auto-sliding

Presentations can be configured to progress through slides automatically, without any user input. To enable this you will need to tell the framework how many milliseconds it should wait between slides:

```javascript
// Slide every five seconds
Reveal.configure({
  autoSlide: 5000
});
```
When this is turned on a control element will appear that enables users to pause and resume auto-sliding. Alternatively, sliding can be paused or resumed by pressing »a« on the keyboard. Sliding is paused automatically as soon as the user starts navigating. You can disable these controls by specifying ```autoSlideStoppable: false``` in your reveal.js config.

You can also override the slide duration for individual slides and fragments by using the ```data-autoslide``` attribute:

```html
<section data-autoslide="2000">
	<p>After 2 seconds the first fragment will be shown.</p>
	<p class="fragment" data-autoslide="10000">After 10 seconds the next fragment will be shown.</p>
	<p class="fragment">Now, the fragment is displayed for 2 seconds before the next slide is shown.</p>
</section>
```

Whenever the auto-slide mode is resumed or paused the ```autoslideresumed``` and ```autoslidepaused``` events are fired.


### Keyboard Bindings

If you're unhappy with any of the default keyboard bindings you can override them using the ```keyboard``` config option:

```javascript
Reveal.configure({
  keyboard: {
    13: 'next', // go to the next slide when the ENTER key is pressed
    27: function() {}, // do something custom when ESC is pressed
    32: null // don't do anything when SPACE is pressed (i.e. disable a reveal.js default binding)
  }
});
```

### Lazy Loading

When working on presentation with a lot of media or iframe content it's important to load lazily. Lazy loading means that reveal.js will only load content for the few slides nearest to the current slide. The number of slides that are preloaded is determined by the `viewDistance` configuration option.

To enable lazy loading all you need to do is change your "src" attributes to "data-src" as shown below. This is supported for image, video, audio and iframe elements. Lazy loaded iframes will also unload when the containing slide is no longer visible.

```html
<section>
  <img data-src="image.png">
  <iframe data-src="http://hakim.se"></iframe>
  <video>
    <source data-src="video.webm" type="video/webm" />
    <source data-src="video.mp4" type="video/mp4" />
  </video>
</section>
```


### API

The ``Reveal`` object exposes a JavaScript API for controlling navigation and reading state:

```javascript
// Navigation
Reveal.slide( indexh, indexv, indexf );
Reveal.left();
Reveal.right();
Reveal.up();
Reveal.down();
Reveal.prev();
Reveal.next();
Reveal.prevFragment();
Reveal.nextFragment();

// Toggle presentation states, optionally pass true/false to force on/off
Reveal.toggleOverview();
Reveal.togglePause();
Reveal.toggleAutoSlide();

// Change a config value at runtime
Reveal.configure({ controls: true });

// Returns the present configuration options
Reveal.getConfig();

// Fetch the current scale of the presentation
Reveal.getScale();

// Retrieves the previous and current slide elements
Reveal.getPreviousSlide();
Reveal.getCurrentSlide();

Reveal.getIndices(); // { h: 0, v: 0 } }
Reveal.getProgress(); // 0-1
Reveal.getTotalSlides();

// State checks
Reveal.isFirstSlide();
Reveal.isLastSlide();
Reveal.isOverview();
Reveal.isPaused();
Reveal.isAutoSliding();
```

### Slide Changed Event

A 'slidechanged' event is fired each time the slide is changed (regardless of state). The event object holds the index values of the current slide as well as a reference to the previous and current slide HTML nodes.

Some libraries, like MathJax (see [#226](https://github.com/hakimel/reveal.js/issues/226#issuecomment-10261609)), get confused by the transforms and display states of slides. Often times, this can be fixed by calling their update or render function from this callback.

```javascript
Reveal.addEventListener( 'slidechanged', function( event ) {
	// event.previousSlide, event.currentSlide, event.indexh, event.indexv
} );
```

### Presentation State

The presentation's current state can be fetched by using the `getState` method. A state object contains all of the information required to put the presentation back as it was when `getState` was first called. Sort of like a snapshot. It's a simple object that can easily be stringified and persisted or sent over the wire.

```javascript
Reveal.slide( 1 );
// we're on slide 1

var state = Reveal.getState();

Reveal.slide( 3 );
// we're on slide 3

Reveal.setState( state );
// we're back on slide 1
```

### Slide States

If you set ``data-state="somestate"`` on a slide ``<section>``, "somestate" will be applied as a class on the document element when that slide is opened. This allows you to apply broad style changes to the page based on the active slide.

Furthermore you can also listen to these changes in state via JavaScript:

```javascript
Reveal.addEventListener( 'somestate', function() {
	// TODO: Sprinkle magic
}, false );
```

### Slide Backgrounds

Slides are contained within a limited portion of the screen by default to allow them to fit any display and scale uniformly. You can apply full page backgrounds outside of the slide area by adding a ```data-background``` attribute to your ```<section>``` elements. Four different types of backgrounds are supported: color, image, video and iframe. Below are a few examples.

```html
<section data-background="#ff0000">
	<h2>All CSS color formats are supported, like rgba() or hsl().</h2>
</section>
<section data-background="http://example.com/image.png">
	<h2>This slide will have a full-size background image.</h2>
</section>
<section data-background="http://example.com/image.png" data-background-size="100px" data-background-repeat="repeat">
	<h2>This background image will be sized to 100px and repeated.</h2>
</section>
<section data-background-video="https://s3.amazonaws.com/static.slid.es/site/homepage/v1/homepage-video-editor.mp4,https://s3.amazonaws.com/static.slid.es/site/homepage/v1/homepage-video-editor.webm" data-background-video-loop>
	<h2>Video. Multiple sources can be defined using a comma separated list. Video will loop when the data-background-video-loop attribute is provided.</h2>
</section>
<section data-background-iframe="https://slides.com">
	<h2>Embeds a web page as a background. Note that the page won't be interactive.</h2>
</section>
```

Backgrounds transition using a fade animation by default. This can be changed to a linear sliding transition by passing ```backgroundTransition: 'slide'``` to the ```Reveal.initialize()``` call. Alternatively you can set ```data-background-transition``` on any section with a background to override that specific transition.


### Parallax Background

If you want to use a parallax scrolling background, set the first two config properties below when initializing reveal.js (the other two are optional).

```javascript
Reveal.initialize({

	// Parallax background image
	parallaxBackgroundImage: '', // e.g. "https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg"

	// Parallax background size
	parallaxBackgroundSize: '', // CSS syntax, e.g. "2100px 900px" - currently only pixels are supported (don't use % or auto)

	// Amount of pixels to move the parallax background per slide step,
	// a value of 0 disables movement along the given axis
	// These are optional, if they aren't specified they'll be calculated automatically
	parallaxBackgroundHorizontal: 200,
	parallaxBackgroundVertical: 50

});
```

Make sure that the background size is much bigger than screen size to allow for some scrolling. [View example](http://lab.hakim.se/reveal-js/?parallaxBackgroundImage=https%3A%2F%2Fs3.amazonaws.com%2Fhakim-static%2Freveal-js%2Freveal-parallax-1.jpg&parallaxBackgroundSize=2100px%20900px).



### Slide Transitions
The global presentation transition is set using the ```transition``` config value. You can override the global transition for a specific slide by using the ```data-transition``` attribute:

```html
<section data-transition="zoom">
	<h2>This slide will override the presentation transition and zoom!</h2>
</section>

<section data-transition-speed="fast">
	<h2>Choose from three transition speeds: default, fast or slow!</h2>
</section>
```

You can also use different in and out transitions for the same slide:

```html
<section data-transition="slide">
    The train goes on … 
</section>
<section data-transition="slide"> 
    and on … 
</section>
<section data-transition="slide-in fade-out"> 
    and stops.
</section>
<section data-transition="fade-in slide-out"> 
    (Passengers entering and leaving)
</section>
<section data-transition="slide">
    And it starts again.
</section>
```


Note that this does not work with the page and cube transitions.


### Internal links

It's easy to link between slides. The first example below targets the index of another slide whereas the second targets a slide with an ID attribute (```<section id="some-slide">```):

```html
<a href="#/2/2">Link</a>
<a href="#/some-slide">Link</a>
```

You can also add relative navigation links, similar to the built in reveal.js controls, by appending one of the following classes on any element. Note that each element is automatically given an ```enabled``` class when it's a valid navigation route based on the current slide.

```html
<a href="#" class="navigate-left">
<a href="#" class="navigate-right">
<a href="#" class="navigate-up">
<a href="#" class="navigate-down">
<a href="#" class="navigate-prev"> <!-- Previous vertical or horizontal slide -->
<a href="#" class="navigate-next"> <!-- Next vertical or horizontal slide -->
```


### Fragments
Fragments are used to highlight individual elements on a slide. Every element with the class ```fragment``` will be stepped through before moving on to the next slide. Here's an example: http://lab.hakim.se/reveal-js/#/fragments

The default fragment style is to start out invisible and fade in. This style can be changed by appending a different class to the fragment:

```html
<section>
	<p class="fragment grow">grow</p>
	<p class="fragment shrink">shrink</p>
	<p class="fragment fade-out">fade-out</p>
	<p class="fragment current-visible">visible only once</p>
	<p class="fragment highlight-current-blue">blue only once</p>
	<p class="fragment highlight-red">highlight-red</p>
	<p class="fragment highlight-green">highlight-green</p>
	<p class="fragment highlight-blue">highlight-blue</p>
</section>
```

Multiple fragments can be applied to the same element sequentially by wrapping it, this will fade in the text on the first step and fade it back out on the second.

```html
<section>
	<span class="fragment fade-in">
		<span class="fragment fade-out">I'll fade in, then out</span>
	</span>
</section>
```

The display order of fragments can be controlled using the ```data-fragment-index``` attribute.

```html
<section>
	<p class="fragment" data-fragment-index="3">Appears last</p>
	<p class="fragment" data-fragment-index="1">Appears first</p>
	<p class="fragment" data-fragment-index="2">Appears second</p>
</section>
```

### Fragment events

When a slide fragment is either shown or hidden reveal.js will dispatch an event.

Some libraries, like MathJax (see #505), get confused by the initially hidden fragment elements. Often times this can be fixed by calling their update or render function from this callback.

```javascript
Reveal.addEventListener( 'fragmentshown', function( event ) {
	// event.fragment = the fragment DOM element
} );
Reveal.addEventListener( 'fragmenthidden', function( event ) {
	// event.fragment = the fragment DOM element
} );
```

### Code syntax highlighting

By default, Reveal is configured with [highlight.js](http://softwaremaniacs.org/soft/highlight/en/) for code syntax highlighting. Below is an example with clojure code that will be syntax highlighted. When the `data-trim` attribute is present surrounding whitespace is automatically removed.

```html
<section>
	<pre><code data-trim>
(def lazy-fib
  (concat
   [0 1]
   ((fn rfib [a b]
        (lazy-cons (+ a b) (rfib b (+ a b)))) 0 1)))
	</code></pre>
</section>
```

### Slide number
If you would like to display the page number of the current slide you can do so using the ```slideNumber``` configuration value.

```javascript
// Shows the slide number using default formatting
Reveal.configure({ slideNumber: true });

// Slide number formatting can be configured using these variables:
//  h: current slide's horizontal index
//  v: current slide's vertical index
//  c: current slide index (flattened)
//  t: total number of slides (flattened)
Reveal.configure({ slideNumber: 'c / t' });

```


### Overview mode

Press "Esc" or "o" keys to toggle the overview mode on and off. While you're in this mode, you can still navigate between slides,
as if you were at 1,000 feet above your presentation. The overview mode comes with a few API hooks:

```javascript
Reveal.addEventListener( 'overviewshown', function( event ) { /* ... */ } );
Reveal.addEventListener( 'overviewhidden', function( event ) { /* ... */ } );

// Toggle the overview mode programmatically
Reveal.toggleOverview();
```

### Fullscreen mode
Just press »F« on your keyboard to show your presentation in fullscreen mode. Press the »ESC« key to exit fullscreen mode.


### Embedded media
Embedded HTML5 `<video>`/`<audio>` and YouTube iframes are automatically paused when you navigate away from a slide. This can be disabled by decorating your element with a `data-ignore` attribute.

Add `data-autoplay` to your media element if you want it to automatically start playing when the slide is shown:

```html
<video data-autoplay src="http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4"></video>
```

Additionally the framework automatically pushes two [post messages](https://developer.mozilla.org/en-US/docs/Web/API/Window.postMessage) to all iframes, ```slide:start``` when the slide containing the iframe is made visible and ```slide:stop``` when it is hidden.


### Stretching elements
Sometimes it's desirable to have an element, like an image or video, stretch to consume as much space as possible within a given slide. This can be done by adding the ```.stretch``` class to an element as seen below:

```html
<section>
	<h2>This video will use up the remaining space on the slide</h2>
    <video class="stretch" src="http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4"></video>
</section>
```

Limitations:
- Only direct descendants of a slide section can be stretched
- Only one descendant per slide section can be stretched


### postMessage API
The framework has a built-in postMessage API that can be used when communicating with a presentation inside of another window. Here's an example showing how you'd make a reveal.js instance in the given window proceed to slide 2:

```javascript
<window>.postMessage( JSON.stringify({ method: 'slide', args: [ 2 ] }), '*' );
```

When reveal.js runs inside of an iframe it can optionally bubble all of its events to the parent. Bubbled events are stringified JSON with three fields: namespace, eventName and state. Here's how you subscribe to them from the parent window:

```javascript
window.addEventListener( 'message', function( event ) {
	var data = JSON.parse( event.data );
	if( data.namespace === 'reveal' && data.eventName ='slidechanged' ) {
		// Slide changed, see data.state for slide number
	}
} );
```

This cross-window messaging can be toggled on or off using configuration flags.

```javascript
Reveal.initialize({
	...,

	// Exposes the reveal.js API through window.postMessage
	postMessage: true,

	// Dispatches all reveal.js events to the parent window through postMessage
	postMessageEvents: false
});
```


## PDF Export

Presentations can be exported to PDF via a special print stylesheet. This feature requires that you use [Google Chrome](http://google.com/chrome).
Here's an example of an exported presentation that's been uploaded to SlideShare: http://www.slideshare.net/hakimel/revealjs-300.

1. Open your presentation with `print-pdf` included anywhere in the query string. This triggers the default index HTML to load the PDF print stylesheet ([css/print/pdf.css](https://github.com/hakimel/reveal.js/blob/master/css/print/pdf.css)). You can test this with [lab.hakim.se/reveal-js?print-pdf](http://lab.hakim.se/reveal-js?print-pdf).
2. Open the in-browser print dialog (CMD+P).
3. Change the **Destination** setting to **Save as PDF**.
4. Change the **Layout** to **Landscape**.
5. Change the **Margins** to **None**.
6. Click **Save**.

![Chrome Print Settings](https://s3.amazonaws.com/hakim-static/reveal-js/pdf-print-settings.png)

## Theming

The framework comes with a few different themes included:

- black: Black background, white text, blue links (default theme)
- white: White background, black text, blue links
- league: Gray background, white text, blue links (default theme for reveal.js < 3.0.0)
- beige: Beige background, dark text, brown links
- sky: Blue background, thin white text, blue links
- night: Black background, thick white text, orange links
- serif: Cappuccino background, gray text, brown links
- simple: White background, black text, blue links
- solarized: Cream-colored background, dark green text, blue links

Each theme is available as a separate stylesheet. To change theme you will need to replace **black** below with your desired theme name in index.html:

```html
<link rel="stylesheet" href="css/theme/black.css" id="theme">
```

If you want to add a theme of your own see the instructions here: [/css/theme/README.md](https://github.com/hakimel/reveal.js/blob/master/css/theme/README.md).


## Speaker Notes

reveal.js comes with a speaker notes plugin which can be used to present per-slide notes in a separate browser window. The notes window also gives you a preview of the next upcoming slide so it may be helpful even if you haven't written any notes. Press the 's' key on your keyboard to open the notes window.

Notes are defined by appending an ```<aside>``` element to a slide as seen below. You can add the ```data-markdown``` attribute to the aside element if you prefer writing notes using Markdown.

When used locally, this feature requires that reveal.js [runs from a local web server](#full-setup).

```html
<section>
	<h2>Some Slide</h2>

	<aside class="notes">
		Oh hey, these are some notes. They'll be hidden in your presentation, but you can see them if you open the speaker notes window (hit 's' on your keyboard).
	</aside>
</section>
```

If you're using the external Markdown plugin, you can add notes with the help of a special delimiter:

```html
<section data-markdown="example.md" data-separator="^\n\n\n" data-separator-vertical="^\n\n" data-separator-notes="^Note:"></section>

# Title
## Sub-title

Here is some content...

Note:
This will only display in the notes window.
```

## Server Side Speaker Notes

In some cases it can be desirable to run notes on a separate device from the one you're presenting on. The Node.js-based notes plugin lets you do this using the same note definitions as its client side counterpart. Include the required scripts by adding the following dependencies:

```javascript
Reveal.initialize({
	...

	dependencies: [
		{ src: 'socket.io/socket.io.js', async: true },
		{ src: 'plugin/notes-server/client.js', async: true }
	]
});
```

Then:

1. Install [Node.js](http://nodejs.org/)
2. Run ```npm install```
3. Run ```node plugin/notes-server```


## Multiplexing

The multiplex plugin allows your audience to view the slides of the presentation you are controlling on their own phone, tablet or laptop. As the master presentation navigates the slides, all client presentations will update in real time. See a demo at [http://revealjs.jit.su/](http://revealjs.jit.su).

The multiplex plugin needs the following 3 things to operate:

1. Master presentation that has control
2. Client presentations that follow the master
3. Socket.io server to broadcast events from the master to the clients

More details:

#### Master presentation
Served from a static file server accessible (preferably) only to the presenter. This need only be on your (the presenter's) computer. (It's safer to run the master presentation from your own computer, so if the venue's Internet goes down it doesn't stop the show.) An example would be to execute the following commands in the directory of your master presentation: 

1. ```npm install node-static```
2. ```static```

If you want to use the speaker notes plugin with your master presentation then make sure you have the speaker notes plugin configured correctly along with the configuration shown below, then execute ```node plugin/notes-server``` in the directory of your master presentation. The configuration below will cause it to connect to the socket.io server as a master, as well as launch your speaker-notes/static-file server.

You can then access your master presentation at ```http://localhost:1947```

Example configuration:
```javascript
Reveal.initialize({
	// other options...

	multiplex: {
		// Example values. To generate your own, see the socket.io server instructions.
		secret: '13652805320794272084', // Obtained from the socket.io server. Gives this (the master) control of the presentation
		id: '1ea875674b17ca76', // Obtained from socket.io server
		url: 'revealjs.jit.su:80' // Location of socket.io server
	},

	// Don't forget to add the dependencies
	dependencies: [
		{ src: '//cdnjs.cloudflare.com/ajax/libs/socket.io/0.9.16/socket.io.min.js', async: true },
		{ src: 'plugin/multiplex/master.js', async: true },

		// and if you want speaker notes
		{ src: 'plugin/notes-server/client.js', async: true }

		// other dependencies...
	]
});
```

#### Client presentation
Served from a publicly accessible static file server. Examples include: GitHub Pages, Amazon S3, Dreamhost, Akamai, etc. The more reliable, the better. Your audience can then access the client presentation via ```http://example.com/path/to/presentation/client/index.html```, with the configuration below causing them to connect to the socket.io server as clients.

Example configuration:
```javascript
Reveal.initialize({
	// other options...

	multiplex: {
		// Example values. To generate your own, see the socket.io server instructions.
		secret: null, // null so the clients do not have control of the master presentation
		id: '1ea875674b17ca76', // id, obtained from socket.io server
		url: 'revealjs.jit.su:80' // Location of socket.io server
	},

	// Don't forget to add the dependencies
	dependencies: [
		{ src: '//cdnjs.cloudflare.com/ajax/libs/socket.io/0.9.16/socket.io.min.js', async: true },
		{ src: 'plugin/multiplex/client.js', async: true }

		// other dependencies...
	]
});
```

#### Socket.io server
Server that receives the slideChanged events from the master presentation and broadcasts them out to the connected client presentations. This needs to be publicly accessible. You can run your own socket.io server with the commands:

1. ```npm install```
2. ```node plugin/multiplex```

Or you use the socket.io server at [http://revealjs.jit.su](http://revealjs.jit.su).

You'll need to generate a unique secret and token pair for your master and client presentations. To do so, visit ```http://example.com/token```, where ```http://example.com``` is the location of your socket.io server. Or if you're going to use the socket.io server at [http://revealjs.jit.su](http://revealjs.jit.su), visit [http://revealjs.jit.su/token](http://revealjs.jit.su/token).

You are very welcome to point your presentations at the Socket.io server running at [http://revealjs.jit.su](http://revealjs.jit.su), but availability and stability are not guaranteed. For anything mission critical I recommend you run your own server. It is simple to deploy to nodejitsu, heroku, your own environment, etc.

##### socket.io server as file static server

The socket.io server can play the role of static file server for your client presentation, as in the example at [http://revealjs.jit.su](http://revealjs.jit.su). (Open [http://revealjs.jit.su](http://revealjs.jit.su) in two browsers. Navigate through the slides on one, and the other will update to match.) 

Example configuration:
```javascript
Reveal.initialize({
	// other options...

	multiplex: {
		// Example values. To generate your own, see the socket.io server instructions.
		secret: null, // null so the clients do not have control of the master presentation
		id: '1ea875674b17ca76', // id, obtained from socket.io server
		url: 'example.com:80' // Location of your socket.io server
	},

	// Don't forget to add the dependencies
	dependencies: [
		{ src: '//cdnjs.cloudflare.com/ajax/libs/socket.io/0.9.16/socket.io.min.js', async: true },
		{ src: 'plugin/multiplex/client.js', async: true }

		// other dependencies...
	]
```

It can also play the role of static file server for your master presentation and client presentations at the same time (as long as you don't want to use speaker notes). (Open [http://revealjs.jit.su](http://revealjs.jit.su) in two browsers. Navigate through the slides on one, and the other will update to match. Navigate through the slides on the second, and the first will update to match.) This is probably not desirable, because you don't want your audience to mess with your slides while you're presenting. ;)

Example configuration:
```javascript
Reveal.initialize({
	// other options...

	multiplex: {
		// Example values. To generate your own, see the socket.io server instructions.
		secret: '13652805320794272084', // Obtained from the socket.io server. Gives this (the master) control of the presentation
		id: '1ea875674b17ca76', // Obtained from socket.io server
		url: 'example.com:80' // Location of your socket.io server
	},

	// Don't forget to add the dependencies
	dependencies: [
		{ src: '//cdnjs.cloudflare.com/ajax/libs/socket.io/0.9.16/socket.io.min.js', async: true },
		{ src: 'plugin/multiplex/master.js', async: true },
		{ src: 'plugin/multiplex/client.js', async: true }

		// other dependencies...
	]
});
```

## Leap Motion
The Leap Motion plugin lets you utilize your [Leap Motion](https://www.leapmotion.com/) device to control basic navigation of your presentation. The gestures currently supported are:

##### 1 to 2 fingers
Pointer &mdash; Point to anything on screen. Move your finger past the device to expand the pointer.

##### 1 hand + 3 or more fingers (left/right/up/down)
Navigate through your slides. See config options to invert movements.

##### 2 hands upwards
Toggle the overview mode. Do it a second time to exit the overview.

#### Config Options
You can edit the following options:

| Property          | Default           | Description
| ----------------- |:-----------------:| :-------------
| autoCenter        | true              | Center the pointer based on where you put your finger into the leap motions detection field.
| gestureDelay      | 500               | How long to delay between gestures in milliseconds.
| naturalSwipe      | true              | Swipe as though you were touching a touch screen. Set to false to invert.
| pointerColor      | #00aaff           | The color of the pointer.
| pointerOpacity    | 0.7               | The opacity of the pointer.
| pointerSize       | 15                | The minimum height and width of the pointer.
| pointerTolerance  | 120               | Bigger = slower pointer.


Example configuration:
```js
Reveal.initialize({

	// other options...

	leap: {
		naturalSwipe   : false,    // Invert swipe gestures
		pointerOpacity : 0.5,      // Set pointer opacity to 0.5
		pointerColor   : '#d80000' // Red pointer
	},

	dependencies: [
		{ src: 'plugin/leap/leap.js', async: true }
	]

});
```

## MathJax

If you want to display math equations in your presentation you can easily do so by including this plugin. The plugin is a very thin wrapper around the [MathJax](http://www.mathjax.org/) library. To use it you'll need to include it as a reveal.js dependency, [find our more about dependencies here](#dependencies).

The plugin defaults to using [LaTeX](http://en.wikipedia.org/wiki/LaTeX) but that can be adjusted through the ```math``` configuration object. Note that MathJax is loaded from a remote server. If you want to use it offline you'll need to download a copy of the library and adjust the ```mathjax``` configuration value. 

Below is an example of how the plugin can be configured. If you don't intend to change these values you do not need to include the ```math``` config object at all.

```js
Reveal.initialize({

	// other options ...

	math: {
		mathjax: 'http://cdn.mathjax.org/mathjax/latest/MathJax.js',
		config: 'TeX-AMS_HTML-full'  // See http://docs.mathjax.org/en/latest/config-files.html
	},
	
	dependencies: [
		{ src: 'plugin/math/math.js', async: true }
	]

});
```

Read MathJax's documentation if you need [HTTPS delivery](http://docs.mathjax.org/en/latest/start.html#secure-access-to-the-cdn) or serving of [specific versions](http://docs.mathjax.org/en/latest/configuration.html#loading-mathjax-from-the-cdn) for stability.


## Installation

The **basic setup** is for authoring presentations only. The **full setup** gives you access to all reveal.js features and plugins such as speaker notes as well as the development tasks needed to make changes to the source.

### Basic setup

The core of reveal.js is very easy to install. You'll simply need to download a copy of this repository and open the index.html file directly in your browser.

1. Download the latest version of reveal.js from <https://github.com/hakimel/reveal.js/releases>

2. Unzip and replace the example contents in index.html with your own

3. Open index.html in a browser to view it


### Full setup

Some reveal.js features, like external Markdown and speaker notes, require that presentations run from a local web server. The following instructions will set up such a server as well as all of the development tasks needed to make edits to the reveal.js source code.

1. Install [Node.js](http://nodejs.org/)

2. Install [Grunt](http://gruntjs.com/getting-started#installing-the-cli)

4. Clone the reveal.js repository
   ```sh
   $ git clone https://github.com/hakimel/reveal.js.git
   ```

5. Navigate to the reveal.js folder
   ```sh
   $ cd reveal.js
   ```

6. Install dependencies
   ```sh
   $ npm install
   ```

7. Serve the presentation and monitor source files for changes
   ```sh
   $ grunt serve
   ```

8. Open <http://localhost:8000> to view your presentation

   You can change the port by using `grunt serve --port 8001`.


### Folder Structure
- **css/** Core styles without which the project does not function
- **js/** Like above but for JavaScript
- **plugin/** Components that have been developed as extensions to reveal.js
- **lib/** All other third party assets (JavaScript, CSS, fonts)


## License

MIT licensed

Copyright (C) 2015 Hakim El Hattab, http://hakim.se