Reveal.js-d3 (reveald3)

Reveal.js plugin to integrate any javascript-based visualization (from pure D3 visualizations to visualizations made with react-based libraries, like semiotic for example) into HTML slides and trigger transitions/animations fully compatible with the Reveal.js data-fragment-index fragements attribute. More generally, you can embed anything that can be rendered in an .html file (including embedding of a full website, served locally or remotely). Check out the live demo (navigate from slide to slide with right/left arrows) and code of the demo examples.

Browser compatibility:

I recommend using a recent version of the Chrome browser when presenting a Reveal.js presentation making use of this plugin. (The plugin is compatible with Firefox and Safari, but compatibility with the lazy-loading options depends on the version used.)

Principal features:

The development of this plugin has been inspired by Reveal.js-d3js-plugin, but has some major differences:

• the plugin itself is not dependent on D3 and does not require to add D3 as a dependencies of Reveal.js
• the visualizations are loaded only when the slide hosting them becomes active (to prevent performance issues).
• the plugin is compatible with Reveal.js lazy loading configurations (see Advanced configuration) if you need to pre-load some heavy visualizations before the slide becomes active.
• the visualizations are deloaded when the slide is not active anymore (e.g.: navigation to previous/next slide) or is out of the viewDistance option of Reveal.js. So the browser is not overloaded by running multiples iframes in the background.
• this plugin support the insertion of multiple visualizations on the same slide (and even multiple visualizations on the same slide + visualization on the background, if you're into this kind of things).
• the triggering of the transitions for the visualizations is fully compatible with Reveal.js data-fragment-index feature.
• Any javascript-based visualizations are supported (slide examples: D3 visualizations, Semiotic (React-based) visualisations, Vega-lite (declarative javascript) visualizations, etc ...).

Installation

1. Copy the file reveald3.js into a local folder, i.e. the plugin/ folder of your Reveal.js presentation.

2. Add the reveald3 plugin to the presentation:

<script src="plugin/reveald3.js"></script>

<script>
    Reveal.initialize({
        // ...
        plugins: [ Reveald3 ],
        // ...
    });
</script>

Usage:

Adding visualization(s) to a slide

To add a visualization to your presentation, simply add a container DOM element (<div>, <span>, etc ...) with the class fig-container, and give it a data-file attribute with the path of the html file hosting the javascript-based visualization that you want to embed.

<section>
    <div class="fig-container"
         data-file="d3-fig/eclipses.html"></div> <!-- path to the html file with visualization code -->
</section>

To embed more than one visualization, simply create multiple containers:

<section>
    <h3>Two visualizations side by side</h3>
    <div class="row">
        <div class="fig-container col-50" data-file="d3-fig/gooey.html"></div>
        <div class="fig-container col-50" data-file="d3-fig/modular-multiplication.html"></div>
        </div>
</section>

Note on background insertion:

You can also embed the visualization in the background of the slide by adding the fig-container class directly to the section element of your Reveal.js code. Note that by default when you embed a visualization in the background, it will be considered as a true Reveal.js slide background (meaning it can an extend outside of the slide area). If you still want your embedded content to be contained within the limited portion of the screen defined by the slide area, you can add the data-no-background attribute (see Advanced configuration).

It is very important NOT to insert the background iframe with Reveal.js's own data-background-iframe attribute. Just add the fig-container class to the <section> (with or without the data-no-background attribute described above and the data-preload attribute described in the advanced configuration section).

DO THIS:

<section class="fig-container"
        data-file="d3-fig/collision-detection.html">
    <h2>Some title</h2>

    <p>some text</p>
</section>

// or with data-no-background for keeping the visualization inside the
// boundaries of the slide

<section class="fig-container"
        data-file="d3-fig/collision-detection.html"
        data-no-background>
    <h2>Some title</h2>

    <p>some text</p>
</section>

DO NOT DO THIS:

<section class="fig-container"
         data-background-iframe="d3-fig/collision-detection.html">
    <h2>Some title</h2>

    <p>some text</p>
</section>

Embedding a website into a slide

You can also directly provide a url to embed whatever is served at this url. This will work for local (e.g.: http://localhost/4300) or remote (any website address) urls

<!-- Include a beautiful website directly in your presentation -->
<section class="fig-container" 
         data-file="https://students.brown.edu/seeing-theory/" 
</section>

Advanced styling of the embedded iframe

Direct styling of the iframe your visualization will be embedded in can be controlled via the data-style attribute. The format of the styles string provided follows the same pattern you would use to inline-style any DOM element. Any valid CSS attribute can be used. Directly styling the iframe could be useful for example if you would like to show only part of a visualization you made, or part of a website you would like to display (in a similar way of how you would use the viewbox attribute in an svg to define the boundaries of an area to display). In this case, you would play with the margin-top/margin-left as well as the height/width of the iframe:

<!-- Include a website directly in your presentation  but don't show the header by removing 100px at the top -->
<section>
  <h3>Website without the header</h3>
  <div  class="fig-container" style="overflow:hidden;" 
        data-file="https://students.brown.edu/seeing-theory/" 
        data-style="height: 500px; margin-top: -100px; width: 650px;">
  </div>
</section>

The trick above would work because by default the container hosting your iframe is styled with a style="overflow: hidden;". If you do not want the overflow to be hidden, then you can set the data-overflow-shown attribute to true. If you use the same code than the example above but add data-overflow-shown=true, this will result in adding the top 100px of your visualization (in addition of whatever was shown before) in this particular case, since now the overflow of the container would be shown. See the demo for more information.

<!-- Include a website directly in your presentation and offset the website by 100px up compared to the div -->
<section>
  <h3>Website without the header</h3>
  <div  class="fig-container" style="overflow:hidden;" 
        data-overflow-shown=true
        data-file="https://students.brown.edu/seeing-theory/" 
        data-style="height: 500px; margin-top: -100px; width: 650px;">
  </div>
</section>

Advanced configuration of the embedded iframe

In addition to the data-file and data-style attributes (see above), some properties of the embedded iframe are directly configurable via dedicated attributes:

• data-scroll: "yes" (default) / "no". Controls the scrolling attribute of the iframe. (Thanks @nbremer for the suggestion)
• data-preload (lazy loading): this plugin is compatible with the lazy loading option of Reveal.js. To lazy load the iframe, set the viewDistance option in the Reveal configuration and add the data-preload attribute to your container. See the demo to see this feature in action. This will work for visualizations embedded in slides or in the background.
• data-no-background: When you embed a visualization in the background, it will be considered as a true Reveal.js slide background (and so it can extend outside of the slide area). If you want your embedded content to be contained within the limited portion of the screen defined by the slide area, you can add the data-no-background attribute to the <section> tag. See the demo to see this feature in action.

Adding and controlling animations/transitions for the visualization(s)

To add transitions to a visualization, simply create a global (var) variable in the javascript code of your html file with the name _transitions, and assign to it an array of javascript objects defining the transitions functions for each fragment steps. Each javascript object in the _transitions array has to be defined as at least one obligatory name:value pair, and two optional name:value pairs can also be declared:

• transitionForward (obligatory): defines a function for the transition from the current state to the NEXT state of the visualization
• transitionBackward (optional): defines a specific function to be ran for the transition to the PREVIOUS state of the visualization when user navigates back. If no transitionBackward is specified, this will take the transitionForward value of the previous step by default (note that you'll still have to define a transitionBackward function for the first animation of the visualization since there is no previous animation/transition in this case. See example in the demo folder). transitionBackward can also take a "none" value to specify that no animation/function has to be played for the reverse transition.
• index (optional): defines the data-fragment-index step at which the transition has to be triggered. If no index is defined, the transitions will be played in the order they appear in the _transitions array, with the first one getting the 0 index (first fragment played). Note that if the value of the index is a string (e.g.: "onSlideChanged") then this transitions will be triggered when the slide comes into view (forward slide changed event) with the delay set by the onSlideChangedDelay option defined above.

var _transitions = [
    {   transitionForward: () => (function to be run to the next state),
        transitionBackward: () => (function to be run from the next state), // optional
        index: 0 // optional
      }
    ]

Example:

var _transitions = [
      {
        transitionForward: () => recolorize("purple"),
        index: "onSlideChanged" // will be run when the slide comes into view
      },
      {
        transitionForward: () => recolorize("yellow"),
        index: 0 // will be run at the data-fragment-index=0 state
      },
      {
        transitionForward: () => recolorize("red"),
        transitionBackward: () => recolorize("blue"), // different behavior on the way back
        index: 3 // will be run at the data-fragment-index=3 state
      },
      {
        transitionForward: () => resize(0.1, 6),
      }, // no index, so will be played at the next data-fragment-index state (4)
    ]

For each slide containing at least one visualization, the plugin looks at the number and index of each transition in all the arrays _transitions for the different visualization embedded in the slide and automatically creates corresponding fragments (<span>) in the container slide if needed. So there is no need to create empty fragments in the Reveal slide.

Note that each index specified is considered intelligently in context of the Reveal.js fragments already present in the slide. For example, if a slide has already 3 fragements (so the data-fragment-index steps for the slides are 0, 1, 2) and a transition is set to index: 14 in the _transitions array, the plugin will understand that this transition has to be played at the data-fragment-index=3 step (and not really at data-fragment-index=14, since 12 empty steps doesn't make real sense) and will automatically create a <span> with this data-fragment-index.

Configuration

You can configure some options for the behavior of the plugin in your presentation by providing a reveald3 option in the Reveal.js initialization options. Note that all configuration values are optional and will default as specified below.

Reveal.initialize({
    // ...

    reveald3: {
        // Specify if the last state of the visualization has to be
        // triggered when navigating back to a slide from a slide further
        // in the deck (i.e. we come back to the slide from the next slide).
        // By default the last fragment transition will be triggered to
        // show the last state of the visualization. This behavior can be
        // discarded (for example if the transition duration is long
        // or is a very resource-intensive task or there is no need to
        // retrieve the last state of the visualization).
        runLastState: true, // true/false, default: true

        // If a special onSlideChanged transition has been set (if for example 
        // the visualization has been preloaded using the data-preload
        // attribute, and you want a specific transition to happen only when
        // you arrive on the slide), you can choose the delay (in ms) with
        // which such a transition will occur (note that in the case of 
        // no data-preload, if no delay is set then the transition might
        // not occur since the iframe might not be fully loaded yet when 
        // the  function is triggered). // default 0. 
        onSlideChangedDelay: 200,

        // This will prefix the path attributes of the source html paths with the given path.
        // (by default "src" if set to true or with the specified path if string)
        mapPath: false, // true / false / "spefific/path/as/string", default: false
          
        // If true, will try to locate the file at a fallback url without the mapPath prefix in case no file is found
        // at the stipulated url with mapPath
        tryFallbackURL: false, // true/false, default false

        // Checking for file existance has been reported to fail in rare 
        // cases though files did exist. This option is to disable the file checking.
        //see: https://github.com/gcalmettes/reveal.js-d3/issues/10
        disableCheckFile: false, //default false
     },

});