Adicionar
/**
* 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: 0.5.2
* 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
// Getting cross-browser transitionEnd event name.
// It's hard to detect it, so we are using the list based on
// https://developer.mozilla.org/en/CSS/CSS_transitions
var transitionEnd = ({
'transition' : 'transitionEnd',
'OTransition' : 'oTransitionEnd',
'msTransition' : 'MSTransitionEnd', // who knows how it will end up?
'MozTransition' : 'transitionend',
'WebkitTransition' : 'webkitTransitionEnd'
})[pfx("transition")];
// 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 intresting 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;
}
};
// To detect the moment when the transition to step element finished
// we need to handle the transitionEnd event.
//
// It may not sound very hard but to makes things a little bit more
// complicated there are two elements being animated separately:
// `root` (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.
//
// It sounds like a simple counter to two would be enough. Unfortunately
// if there is no change in the transform value (for example scale doesn't
// change between two steps) only one transition (and transitionEnd event)
// will be triggered.
//
// So to properly detect when the transitions finished we need to keep
// the `expectedTransitionTarget` (that can be one of `root` or `canvas`)
// and only call `onStepEnter` then transition ended on the expected one.
var expectedTransitionTarget = null;
var onTransitionEnd = function (event) {
if (event.target === expectedTransitionTarget) {
onStepEnter(activeStep);
}
};
// `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);
root.addEventListener(transitionEnd, onTransitionEnd, false);
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;
};
// `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;
// Because one of the transition is delayed depending on zoom direction,
// the last transition will happen on `root` or `canvas` element.
// Here we store the expected transition event target, to be able to correctly
// trigger `impress:stepenter` event.
expectedTransitionTarget = target.scale > currentState.scale ? root : canvas;
// trigger leave of currently active element (if it's not the same step again)
if (activeStep && activeStep !== el) {
onStepLeave(activeStep);
}
// alter transforms of `root` and `canvas` to trigger transitions
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"
});
// store current state
currentState = target;
activeStep = el;
// manually trigger enter event if duration was set to 0
if (duration === 0) {
onStepEnter(activeStep);
}
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.
Entradas
Es interesante ver como una empresa como esta logra obtener una mayor posesión en el mercado con grandes estrategias como esta.
ResponderEliminar