Lecture Sheets: tizenporta/impress.js@768787695807 (annotated)

tizenporta/impress.js@768787695807 (annotated)

tizenporta/impress.js

Mon, 07 May 2012 23:15:17 +0200

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Mon, 07 May 2012 23:15:17 +0200
changeset 17: 768787695807
permissions: -rw-r--r--

Add Enyo framework following discussion with Eva BRUCHERSEIFER.

 /**
  * impress.js
  *
  * impress.js is a presentation tool based on the power of CSS3 transforms and transitions
  * in modern browsers and inspired by the idea behind prezi.com.
  *
  *
  * Copyright 2011-2012 Bartek Szopka (@bartaz)
  *
  * Released under the MIT and GPL Licenses.
  *
  * ------------------------------------------------
  *  author:  Bartek Szopka
  *  version: 0.5.3
  *  url:     http://bartaz.github.com/impress.js/
  *  source:  http://github.com/bartaz/impress.js/
  */
 /*jshint bitwise:true, curly:true, eqeqeq:true, forin:true, latedef:true, newcap:true,
          noarg:true, noempty:true, undef:true, strict:true, browser:true */
 // You are one of those who like to know how thing work inside?
 // Let me show you the cogs that make impress.js run...
 (function ( document, window ) {
     'use strict';
     // HELPER FUNCTIONS
     // `pfx` is a function that takes a standard CSS property name as a parameter
     // and returns it's prefixed version valid for current browser it runs in.
     // The code is heavily inspired by Modernizr http://www.modernizr.com/
     var pfx = (function () {
         var style = document.createElement('dummy').style,
             prefixes = 'Webkit Moz O ms Khtml'.split(' '),
             memory = {};
         return function ( prop ) {
             if ( typeof memory[ prop ] === "undefined" ) {
                 var ucProp  = prop.charAt(0).toUpperCase() + prop.substr(1),
                     props   = (prop + ' ' + prefixes.join(ucProp + ' ') + ucProp).split(' ');
                 memory[ prop ] = null;
                 for ( var i in props ) {
                     if ( style[ props[i] ] !== undefined ) {
                         memory[ prop ] = props[i];
                         break;
                     }
                 }
             }
             return memory[ prop ];
         };
     })();
     // `arraify` takes an array-like object and turns it into real Array
     // to make all the Array.prototype goodness available.
     var arrayify = function ( a ) {
         return [].slice.call( a );
     };
     // `css` function applies the styles given in `props` object to the element
     // given as `el`. It runs all property names through `pfx` function to make
     // sure proper prefixed version of the property is used.
     var css = function ( el, props ) {
         var key, pkey;
         for ( key in props ) {
             if ( props.hasOwnProperty(key) ) {
                 pkey = pfx(key);
                 if ( pkey !== null ) {
                     el.style[pkey] = props[key];
                 }
             }
         }
         return el;
     };
     // `toNumber` takes a value given as `numeric` parameter and tries to turn
     // it into a number. If it is not possible it returns 0 (or other value
     // given as `fallback`).
     var toNumber = function (numeric, fallback) {
         return isNaN(numeric) ? (fallback || 0) : Number(numeric);
     };
     // `byId` returns element with given `id` - you probably have guessed that ;)
     var byId = function ( id ) {
         return document.getElementById(id);
     };
     // `$` returns first element for given CSS `selector` in the `context` of
     // the given element or whole document.
     var $ = function ( selector, context ) {
         context = context || document;
         return context.querySelector(selector);
     };
     // `$$` return an array of elements for given CSS `selector` in the `context` of
     // the given element or whole document.
     var $$ = function ( selector, context ) {
         context = context || document;
         return arrayify( context.querySelectorAll(selector) );
     };
     // `triggerEvent` builds a custom DOM event with given `eventName` and `detail` data
     // and triggers it on element given as `el`.
     var triggerEvent = function (el, eventName, detail) {
         var event = document.createEvent("CustomEvent");
         event.initCustomEvent(eventName, true, true, detail);
         el.dispatchEvent(event);
     };
     // `translate` builds a translate transform string for given data.
     var translate = function ( t ) {
         return " translate3d(" + t.x + "px," + t.y + "px," + t.z + "px) ";
     };
     // `rotate` builds a rotate transform string for given data.
     // By default the rotations are in X Y Z order that can be reverted by passing `true`
     // as second parameter.
     var rotate = function ( r, revert ) {
         var rX = " rotateX(" + r.x + "deg) ",
             rY = " rotateY(" + r.y + "deg) ",
             rZ = " rotateZ(" + r.z + "deg) ";
         return revert ? rZ+rY+rX : rX+rY+rZ;
     };
     // `scale` builds a scale transform string for given data.
     var scale = function ( s ) {
         return " scale(" + s + ") ";
     };
     // `perspective` builds a perspective transform string for given data.
     var perspective = function ( p ) {
         return " perspective(" + p + "px) ";
     };
     // `getElementFromHash` returns an element located by id from hash part of
     // window location.
     var getElementFromHash = function () {
         // get id from url # by removing `#` or `#/` from the beginning,
         // so both "fallback" `#slide-id` and "enhanced" `#/slide-id` will work
         return byId( window.location.hash.replace(/^#\/?/,"") );
     };
     // `computeWindowScale` counts the scale factor between window size and size
     // defined for the presentation in the config.
     var computeWindowScale = function ( config ) {
         var hScale = window.innerHeight / config.height,
             wScale = window.innerWidth / config.width,
             scale = hScale > wScale ? wScale : hScale;
         if (config.maxScale && scale > config.maxScale) {
             scale = config.maxScale;
         }
         if (config.minScale && scale < config.minScale) {
             scale = config.minScale;
         }
         return scale;
     };
     // CHECK SUPPORT
     var body = document.body;
     var ua = navigator.userAgent.toLowerCase();
     var impressSupported =
                           // browser should support CSS 3D transtorms
                            ( pfx("perspective") !== null ) &&
                           // and `classList` and `dataset` APIs
                            ( body.classList ) &&
                            ( body.dataset ) &&
                           // but some mobile devices need to be blacklisted,
                           // because their CSS 3D support or hardware is not
                           // good enough to run impress.js properly, sorry...
                            ( ua.search(/(iphone)|(ipod)|(android)/) === -1 );
     if (!impressSupported) {
         // we can't be sure that `classList` is supported
         body.className += " impress-not-supported ";
     } else {
         body.classList.remove("impress-not-supported");
         body.classList.add("impress-supported");
     }
     // GLOBALS AND DEFAULTS
     // This is were the root elements of all impress.js instances will be kept.
     // Yes, this means you can have more than one instance on a page, but I'm not
     // sure if it makes any sense in practice ;)
     var roots = {};
     // some default config values.
     var defaults = {
         width: 1024,
         height: 768,
         maxScale: 1,
         minScale: 0,
         perspective: 1000,
         transitionDuration: 1000
     };
     // it's just an empty function ... and a useless comment.
     var empty = function () { return false; };
     // IMPRESS.JS API
     // And that's where interesting things will start to happen.
     // It's the core `impress` function that returns the impress.js API
     // for a presentation based on the element with given id ('impress'
     // by default).
     var impress = window.impress = function ( rootId ) {
         // If impress.js is not supported by the browser return a dummy API
         // it may not be a perfect solution but we return early and avoid
         // running code that may use features not implemented in the browser.
         if (!impressSupported) {
             return {
                 init: empty,
                 goto: empty,
                 prev: empty,
                 next: empty
             };
         }
         rootId = rootId || "impress";
         // if given root is already initialized just return the API
         if (roots["impress-root-" + rootId]) {
             return roots["impress-root-" + rootId];
         }
         // data of all presentation steps
         var stepsData = {};
         // element of currently active step
         var activeStep = null;
         // current state (position, rotation and scale) of the presentation
         var currentState = null;
         // array of step elements
         var steps = null;
         // configuration options
         var config = null;
         // scale factor of the browser window
         var windowScale = null;
         // root presentation elements
         var root = byId( rootId );
         var canvas = document.createElement("div");
         var initialized = false;
         // STEP EVENTS
         //
         // There are currently two step events triggered by impress.js
         // `impress:stepenter` is triggered when the step is shown on the
         // screen (the transition from the previous one is finished) and
         // `impress:stepleave` is triggered when the step is left (the
         // transition to next step just starts).
         // reference to last entered step
         var lastEntered = null;
         // `onStepEnter` is called whenever the step element is entered
         // but the event is triggered only if the step is different than
         // last entered step.
         var onStepEnter = function (step) {
             if (lastEntered !== step) {
                 triggerEvent(step, "impress:stepenter");
                 lastEntered = step;
             }
         };
         // `onStepLeave` is called whenever the step element is left
         // but the event is triggered only if the step is the same as
         // last entered step.
         var onStepLeave = function (step) {
             if (lastEntered === step) {
                 triggerEvent(step, "impress:stepleave");
                 lastEntered = null;
             }
         };
         // `initStep` initializes given step element by reading data from its
         // data attributes and setting correct styles.
         var initStep = function ( el, idx ) {
             var data = el.dataset,
                 step = {
                     translate: {
                         x: toNumber(data.x),
                         y: toNumber(data.y),
                         z: toNumber(data.z)
                     },
                     rotate: {
                         x: toNumber(data.rotateX),
                         y: toNumber(data.rotateY),
                         z: toNumber(data.rotateZ || data.rotate)
                     },
                     scale: toNumber(data.scale, 1),
                     el: el
                 };
             if ( !el.id ) {
                 el.id = "step-" + (idx + 1);
             }
             stepsData["impress-" + el.id] = step;
             css(el, {
                 position: "absolute",
                 transform: "translate(-50%,-50%)" +
                            translate(step.translate) +
                            rotate(step.rotate) +
                            scale(step.scale),
                 transformStyle: "preserve-3d"
             });
         };
         // `init` API function that initializes (and runs) the presentation.
         var init = function () {
             if (initialized) { return; }
             // First we set up the viewport for mobile devices.
             // For some reason iPad goes nuts when it is not done properly.
             var meta = $("meta[name='viewport']") || document.createElement("meta");
             meta.content = "width=device-width, minimum-scale=1, maximum-scale=1, user-scalable=no";
             if (meta.parentNode !== document.head) {
                 meta.name = 'viewport';
                 document.head.appendChild(meta);
             }
             // initialize configuration object
             var rootData = root.dataset;
             config = {
                 width: toNumber( rootData.width, defaults.width ),
                 height: toNumber( rootData.height, defaults.height ),
                 maxScale: toNumber( rootData.maxScale, defaults.maxScale ),
                 minScale: toNumber( rootData.minScale, defaults.minScale ),
                 perspective: toNumber( rootData.perspective, defaults.perspective ),
                 transitionDuration: toNumber( rootData.transitionDuration, defaults.transitionDuration )
             };
             windowScale = computeWindowScale( config );
             // wrap steps with "canvas" element
             arrayify( root.childNodes ).forEach(function ( el ) {
                 canvas.appendChild( el );
             });
             root.appendChild(canvas);
             // set initial styles
             document.documentElement.style.height = "100%";
             css(body, {
                 height: "100%",
                 overflow: "hidden"
             });
             var rootStyles = {
                 position: "absolute",
                 transformOrigin: "top left",
                 transition: "all 0s ease-in-out",
                 transformStyle: "preserve-3d"
             };
             css(root, rootStyles);
             css(root, {
                 top: "50%",
                 left: "50%",
                 transform: perspective( config.perspective/windowScale ) + scale( windowScale )
             });
             css(canvas, rootStyles);
             body.classList.remove("impress-disabled");
             body.classList.add("impress-enabled");
             // get and init steps
             steps = $$(".step", root);
             steps.forEach( initStep );
             // set a default initial state of the canvas
             currentState = {
                 translate: { x: 0, y: 0, z: 0 },
                 rotate:    { x: 0, y: 0, z: 0 },
                 scale:     1
             };
             initialized = true;
             triggerEvent(root, "impress:init", { api: roots[ "impress-root-" + rootId ] });
         };
         // `getStep` is a helper function that returns a step element defined by parameter.
         // If a number is given, step with index given by the number is returned, if a string
         // is given step element with such id is returned, if DOM element is given it is returned
         // if it is a correct step element.
         var getStep = function ( step ) {
             if (typeof step === "number") {
                 step = step < 0 ? steps[ steps.length + step] : steps[ step ];
             } else if (typeof step === "string") {
                 step = byId(step);
             }
             return (step && step.id && stepsData["impress-" + step.id]) ? step : null;
         };
         // used to reset timeout for `impress:stepenter` event
         var stepEnterTimeout = null;
         // `goto` API function that moves to step given with `el` parameter (by index, id or element),
         // with a transition `duration` optionally given as second parameter.
         var goto = function ( el, duration ) {
             if ( !initialized || !(el = getStep(el)) ) {
                 // presentation not initialized or given element is not a step
                 return false;
             }
             // Sometimes it's possible to trigger focus on first link with some keyboard action.
             // Browser in such a case tries to scroll the page to make this element visible
             // (even that body overflow is set to hidden) and it breaks our careful positioning.
             //
             // So, as a lousy (and lazy) workaround we will make the page scroll back to the top
             // whenever slide is selected
             //
             // If you are reading this and know any better way to handle it, I'll be glad to hear about it!
             window.scrollTo(0, 0);
             var step = stepsData["impress-" + el.id];
             if ( activeStep ) {
                 activeStep.classList.remove("active");
                 body.classList.remove("impress-on-" + activeStep.id);
             }
             el.classList.add("active");
             body.classList.add("impress-on-" + el.id);
             // compute target state of the canvas based on given step
             var target = {
                 rotate: {
                     x: -step.rotate.x,
                     y: -step.rotate.y,
                     z: -step.rotate.z
                 },
                 translate: {
                     x: -step.translate.x,
                     y: -step.translate.y,
                     z: -step.translate.z
                 },
                 scale: 1 / step.scale
             };
             // Check if the transition is zooming in or not.
             //
             // This information is used to alter the transition style:
             // when we are zooming in - we start with move and rotate transition
             // and the scaling is delayed, but when we are zooming out we start
             // with scaling down and move and rotation are delayed.
             var zoomin = target.scale >= currentState.scale;
             duration = toNumber(duration, config.transitionDuration);
             var delay = (duration / 2);
             // if the same step is re-selected, force computing window scaling,
             // because it is likely to be caused by window resize
             if (el === activeStep) {
                 windowScale = computeWindowScale(config);
             }
             var targetScale = target.scale * windowScale;
             // trigger leave of currently active element (if it's not the same step again)
             if (activeStep && activeStep !== el) {
                 onStepLeave(activeStep);
             }
             // Now we alter transforms of `root` and `canvas` to trigger transitions.
             //
             // And here is why there are two elements: `root` and `canvas` - they are
             // being animated separately:
             // `root` is used for scaling and `canvas` for translate and rotations.
             // Transitions on them are triggered with different delays (to make
             // visually nice and 'natural' looking transitions), so we need to know
             // that both of them are finished.
             css(root, {
                 // to keep the perspective look similar for different scales
                 // we need to 'scale' the perspective, too
                 transform: perspective( config.perspective / targetScale ) + scale( targetScale ),
                 transitionDuration: duration + "ms",
                 transitionDelay: (zoomin ? delay : 0) + "ms"
             });
             css(canvas, {
                 transform: rotate(target.rotate, true) + translate(target.translate),
                 transitionDuration: duration + "ms",
                 transitionDelay: (zoomin ? 0 : delay) + "ms"
             });
             // Here is a tricky part...
             //
             // If there is no change in scale or no change in rotation and translation, it means there was actually
             // no delay - because there was no transition on `root` or `canvas` elements.
             // We want to trigger `impress:stepenter` event in the correct moment, so here we compare the current
             // and target values to check if delay should be taken into account.
             //
             // I know that this `if` statement looks scary, but it's pretty simple when you know what is going on
             // - it's simply comparing all the values.
             if ( currentState.scale === target.scale ||
                 (currentState.rotate.x === target.rotate.x && currentState.rotate.y === target.rotate.y &&
                  currentState.rotate.z === target.rotate.z && currentState.translate.x === target.translate.x &&
                  currentState.translate.y === target.translate.y && currentState.translate.z === target.translate.z) ) {
                 delay = 0;
             }
             // store current state
             currentState = target;
             activeStep = el;
             // And here is where we trigger `impress:stepenter` event.
             // We simply set up a timeout to fire it taking transition duration (and possible delay) into account.
             //
             // I really wanted to make it in more elegant way. The `transitionend` event seemed to be the best way
             // to do it, but the fact that I'm using transitions on two separate elements and that the `transitionend`
             // event is only triggered when there was a transition (change in the values) caused some bugs and
             // made the code really complicated, cause I had to handle all the conditions separately. And it still
             // needed a `setTimeout` fallback for the situations when there is no transition at all.
             // So I decided that I'd rather make the code simpler than use shiny new `transitionend`.
             //
             // If you want learn something interesting and see how it was done with `transitionend` go back to
             // version 0.5.2 of impress.js: http://github.com/bartaz/impress.js/blob/0.5.2/js/impress.js
             window.clearTimeout(stepEnterTimeout);
             stepEnterTimeout = window.setTimeout(function() {
                 onStepEnter(activeStep);
             }, duration + delay);
             return el;
         };
         // `prev` API function goes to previous step (in document order)
         var prev = function () {
             var prev = steps.indexOf( activeStep ) - 1;
             prev = prev >= 0 ? steps[ prev ] : steps[ steps.length-1 ];
             return goto(prev);
         };
         // `next` API function goes to next step (in document order)
         var next = function () {
             var next = steps.indexOf( activeStep ) + 1;
             next = next < steps.length ? steps[ next ] : steps[ 0 ];
             return goto(next);
         };
         // Adding some useful classes to step elements.
         //
         // All the steps that have not been shown yet are given `future` class.
         // When the step is entered the `future` class is removed and the `present`
         // class is given. When the step is left `present` class is replaced with
         // `past` class.
         //
         // So every step element is always in one of three possible states:
         // `future`, `present` and `past`.
         //
         // There classes can be used in CSS to style different types of steps.
         // For example the `present` class can be used to trigger some custom
         // animations when step is shown.
         root.addEventListener("impress:init", function(){
             // STEP CLASSES
             steps.forEach(function (step) {
                 step.classList.add("future");
             });
             root.addEventListener("impress:stepenter", function (event) {
                 event.target.classList.remove("past");
                 event.target.classList.remove("future");
                 event.target.classList.add("present");
             }, false);
             root.addEventListener("impress:stepleave", function (event) {
                 event.target.classList.remove("present");
                 event.target.classList.add("past");
             }, false);
         }, false);
         // Adding hash change support.
         root.addEventListener("impress:init", function(){
             // last hash detected
             var lastHash = "";
             // `#/step-id` is used instead of `#step-id` to prevent default browser
             // scrolling to element in hash.
             //
             // And it has to be set after animation finishes, because in Chrome it
             // makes transtion laggy.
             // BUG: http://code.google.com/p/chromium/issues/detail?id=62820
             root.addEventListener("impress:stepenter", function (event) {
                 window.location.hash = lastHash = "#/" + event.target.id;
             }, false);
             window.addEventListener("hashchange", function () {
                 // When the step is entered hash in the location is updated
                 // (just few lines above from here), so the hash change is
                 // triggered and we would call `goto` again on the same element.
                 //
                 // To avoid this we store last entered hash and compare.
                 if (window.location.hash !== lastHash) {
                     goto( getElementFromHash() );
                 }
             }, false);
             // START
             // by selecting step defined in url or first step of the presentation
             goto(getElementFromHash() || steps[0], 0);
         }, false);
         body.classList.add("impress-disabled");
         // store and return API for given impress.js root element
         return (roots[ "impress-root-" + rootId ] = {
             init: init,
             goto: goto,
             next: next,
             prev: prev
         });
     };
     // flag that can be used in JS to check if browser have passed the support test
     impress.supported = impressSupported;
 })(document, window);
 // NAVIGATION EVENTS
 // As you can see this part is separate from the impress.js core code.
 // It's because these navigation actions only need what impress.js provides with
 // its simple API.
 //
 // In future I think about moving it to make them optional, move to separate files
 // and treat more like a 'plugins'.
 (function ( document, window ) {
     'use strict';
     // throttling function calls, by Remy Sharp
     // http://remysharp.com/2010/07/21/throttling-function-calls/
     var throttle = function (fn, delay) {
         var timer = null;
         return function () {
             var context = this, args = arguments;
             clearTimeout(timer);
             timer = setTimeout(function () {
                 fn.apply(context, args);
             }, delay);
         };
     };
     // wait for impress.js to be initialized
     document.addEventListener("impress:init", function (event) {
         // Getting API from event data.
         // So you don't event need to know what is the id of the root element
         // or anything. `impress:init` event data gives you everything you
         // need to control the presentation that was just initialized.
         var api = event.detail.api;
         // KEYBOARD NAVIGATION HANDLERS
         // Prevent default keydown action when one of supported key is pressed.
         document.addEventListener("keydown", function ( event ) {
             if ( event.keyCode === 9 || ( event.keyCode >= 32 && event.keyCode <= 34 ) || (event.keyCode >= 37 && event.keyCode <= 40) ) {
                 event.preventDefault();
             }
         }, false);
         // Trigger impress action (next or prev) on keyup.
         // Supported keys are:
         // [space] - quite common in presentation software to move forward
         // [up] [right] / [down] [left] - again common and natural addition,
         // [pgdown] / [pgup] - often triggered by remote controllers,
         // [tab] - this one is quite controversial, but the reason it ended up on
         //   this list is quite an interesting story... Remember that strange part
         //   in the impress.js code where window is scrolled to 0,0 on every presentation
         //   step, because sometimes browser scrolls viewport because of the focused element?
         //   Well, the [tab] key by default navigates around focusable elements, so clicking
         //   it very often caused scrolling to focused element and breaking impress.js
         //   positioning. I didn't want to just prevent this default action, so I used [tab]
         //   as another way to moving to next step... And yes, I know that for the sake of
         //   consistency I should add [shift+tab] as opposite action...
         document.addEventListener("keyup", function ( event ) {
             if ( event.keyCode === 9 || ( event.keyCode >= 32 && event.keyCode <= 34 ) || (event.keyCode >= 37 && event.keyCode <= 40) ) {
                 switch( event.keyCode ) {
                     case 33: // pg up
                     case 37: // left
                     case 38: // up
                              api.prev();
                              break;
                     case 9:  // tab
                     case 32: // space
                     case 34: // pg down
                     case 39: // right
                     case 40: // down
                              api.next();
                              break;
                 }
                 event.preventDefault();
             }
         }, false);
         // delegated handler for clicking on the links to presentation steps
         document.addEventListener("click", function ( event ) {
             // event delegation with "bubbling"
             // check if event target (or any of its parents is a link)
             var target = event.target;
             while ( (target.tagName !== "A") &&
                     (target !== document.documentElement) ) {
                 target = target.parentNode;
             }
             if ( target.tagName === "A" ) {
                 var href = target.getAttribute("href");
                 // if it's a link to presentation step, target this step
                 if ( href && href[0] === '#' ) {
                     target = document.getElementById( href.slice(1) );
                 }
             }
             if ( api.goto(target) ) {
                 event.stopImmediatePropagation();
                 event.preventDefault();
             }
         }, false);
         // delegated handler for clicking on step elements
         document.addEventListener("click", function ( event ) {
             var target = event.target;
             // find closest step element that is not active
             while ( !(target.classList.contains("step") && !target.classList.contains("active")) &&
                     (target !== document.documentElement) ) {
                 target = target.parentNode;
             }
             if ( api.goto(target) ) {
                 event.preventDefault();
             }
         }, false);
         // touch handler to detect taps on the left and right side of the screen
         // based on awesome work of @hakimel: https://github.com/hakimel/reveal.js
         document.addEventListener("touchstart", function ( event ) {
             if (event.touches.length === 1) {
                 var x = event.touches[0].clientX,
                     width = window.innerWidth * 0.3,
                     result = null;
                 if ( x < width ) {
                     result = api.prev();
                 } else if ( x > window.innerWidth - width ) {
                     result = api.next();
                 }
                 if (result) {
                     event.preventDefault();
                 }
             }
         }, false);
         // rescale presentation when window is resized
         window.addEventListener("resize", throttle(function () {
             // force going to active step again, to trigger rescaling
             api.goto( document.querySelector(".active"), 500 );
         }, 250), false);
     }, false);
 })(document, window);
 // THAT'S ALL FOLKS!
 //
 // Thanks for reading it all.
 // Or thanks for scrolling down and reading the last part.
 //
 // I've learnt a lot when building impress.js and I hope this code and comments
 // will help somebody learn at least some part of it.