287 lines
7.3 KiB
JavaScript
287 lines
7.3 KiB
JavaScript
/**
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* Copyright (C) 2011 Hakim El Hattab, http://hakim.se
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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/**
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* Handles the very minimal navigation logic involved in the
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* slideshow. Including keyboard navigation, touch interaction
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* and URL history behavior.
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*
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* Slides are given unique hash based URL's so that they can be
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* opened directly. I didn't use the HTML5 History API for this
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* as it would have required the addition of server side rewrite
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* rules and hence require more effort for anyone to set up.
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*
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* This component can be called from other scripts via a tiny API:
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* - Slideshow.navigateTo( indexh, indexv );
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* - Slideshow.navigateLeft();
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* - Slideshow.navigateRight();
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* - Slideshow.navigateUp();
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* - Slideshow.navigateDown();
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*
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*
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* version 0.1:
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* - First release
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*
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* version 0.2:
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* - Refactored code and added inline documentation
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* - Slides now have unique URL's
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* - A basic API to invoke navigation was added
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*
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* version 0.3:
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* - Added licensing terms
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*
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*
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* @author Hakim El Hattab
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* @version 0.3
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*/
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var Slideshow = (function(){
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var indexh = 0,
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indexv = 0;
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/**
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* Activates the main program logic.
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*/
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function initialize() {
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document.addEventListener('keydown', onDocumentKeyDown, false);
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document.addEventListener('touchstart', onDocumentTouchStart, false);
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window.addEventListener('hashchange', onWindowHashChange, false);
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// Read the initial state of the URL (hash)
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readURL();
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}
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/**
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* Handler for the document level 'keydown' event.
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*
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* @param {Object} event
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*/
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function onDocumentKeyDown( event ) {
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if( event.keyCode >= 37 && event.keyCode <= 40 ) {
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switch( event.keyCode ) {
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case 37: navigateLeft(); break; // left
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case 39: navigateRight(); break; // right
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case 38: navigateUp(); break; // up
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case 40: navigateDown(); break; // down
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}
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slide();
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event.preventDefault();
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}
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}
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/**
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* Handler for the document level 'touchstart' event.
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*
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* This enables very basic tap interaction for touch
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* devices. Added mainly for performance testing of 3D
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* transforms on iOS but was so happily surprised with
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* how smoothly it runs so I left it in here. Apple +1
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*
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* @param {Object} event
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*/
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function onDocumentTouchStart( event ) {
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// We're only interested in one point taps
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if (event.touches.length === 1) {
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// Never prevent taps on anchors and images
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if( event.target.tagName.toLowerCase() === 'a' || event.target.tagName.toLowerCase() === 'img' ) {
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return;
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}
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event.preventDefault();
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var point = {
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x: event.touches[0].clientX,
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y: event.touches[0].clientY
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};
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// Define the extent of the areas that may be tapped
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// to navigate
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var wt = window.innerWidth * 0.3;
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var ht = window.innerHeight * 0.3;
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if( point.x < wt ) {
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navigateLeft();
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}
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else if( point.x > window.innerWidth - wt ) {
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navigateRight();
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}
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else if( point.y < ht ) {
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navigateUp();
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}
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else if( point.y > window.innerHeight - ht ) {
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navigateDown();
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}
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slide();
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}
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}
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/**
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* Handler for the window level 'hashchange' event.
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*
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* @param {Object} event
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*/
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function onWindowHashChange( event ) {
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readURL();
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}
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/**
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* Updates one dimension of slides by showing the slide
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* with the specified index.
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*
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* @param {String} selector A CSS selector that will fetch
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* the group of slides we are working with
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* @param {Number} index The index of the slide that should be
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* shown
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*
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* @return {Number} The index of the slide that is now shown,
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* might differ from the passed in index if it was out of
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* bounds.
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*/
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function updateSlides( selector, index ) {
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// Select all slides and convert the NodeList result to
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// an array
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var slides = Array.prototype.slice.call( document.querySelectorAll( selector ) );
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if( slides.length ) {
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// Enforce max and minimum index bounds
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index = Math.max(Math.min(index, slides.length - 1), 0);
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slides[index].setAttribute('class', 'present');
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// Any element previous to index is given the 'past' class
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slides.slice(0, index).map(function(element){
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element.setAttribute('class', 'past');
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});
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// Any element subsequent to index is given the 'future' class
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slides.slice(index + 1).map(function(element){
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element.setAttribute('class', 'future');
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});
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}
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else {
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// Since there are no slides we can't be anywhere beyond the
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// zeroth index
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index = 0;
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}
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return index;
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}
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/**
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* Updates the visual slides to represent the currently
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* set indices.
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*/
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function slide() {
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indexh = updateSlides( '#main>section', indexh );
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indexv = updateSlides( 'section.present>section', indexv );
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writeURL();
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}
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/**
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* Reads the current URL (hash) and navigates accordingly.
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*/
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function readURL() {
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// Break the hash down to separate components
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var bits = window.location.hash.slice(2).split('/');
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// Read the index components of the hash
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indexh = bits[0] ? parseInt( bits[0] ) : 0;
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indexv = bits[1] ? parseInt( bits[1] ) : 0;
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navigateTo( indexh, indexv );
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}
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/**
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* Updates the page URL (hash) to reflect the current
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* navigational state.
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*/
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function writeURL() {
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var url = '/';
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// Only include the minimum possible number of components in
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// the URL
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if( indexh > 0 || indexv > 0 ) url += indexh
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if( indexv > 0 ) url += '/' + indexv
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window.location.hash = url;
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}
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/**
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* Triggers a navigation to the specified indices.
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*
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* @param {Number} h The horizontal index of the slide to show
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* @param {Number} v The vertical index of the slide to show
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*/
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function navigateTo( h, v ) {
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indexh = h === undefined ? indexh : h;
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indexv = v === undefined ? indexv : v;
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slide();
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}
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function navigateLeft() {
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indexh --;
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indexv = 0;
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slide();
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}
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function navigateRight() {
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indexh ++;
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indexv = 0;
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slide();
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}
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function navigateUp() {
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indexv --;
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slide();
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}
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function navigateDown() {
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indexv ++;
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slide();
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}
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// Initialize the program. Done right before returning to ensure
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// that any inline variable definitions are available to all
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// functions
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initialize();
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// Expose some methods publicly
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return {
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navigateTo: navigateTo,
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navigateLeft: navigateLeft,
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navigateRight: navigateRight,
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navigateUp: navigateUp,
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navigateDown: navigateDown
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};
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})();
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