115 lines
3.2 KiB
JavaScript
115 lines
3.2 KiB
JavaScript
/**
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* Blackout plugin
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*
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* Press Ctrl+b to hide all slides, and Ctrl+b again to show them.
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* Also navigating to a different slide will show them again (impress:stepleave).
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*
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* Copyright 2014 @Strikeskids
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* Released under the MIT license.
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*/
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/* global document */
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( function( document ) {
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"use strict";
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var canvas = null;
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var blackedOut = false;
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// While waiting for a shared library of utilities, copying these 2 from main impress.js
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var css = function( el, props ) {
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var key, pkey;
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for ( key in props ) {
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if ( props.hasOwnProperty( key ) ) {
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pkey = pfx( key );
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if ( pkey !== null ) {
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el.style[ pkey ] = props[ key ];
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}
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}
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}
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return el;
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};
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var pfx = ( function() {
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var style = document.createElement( "dummy" ).style,
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prefixes = "Webkit Moz O ms Khtml".split( " " ),
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memory = {};
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return function( prop ) {
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if ( typeof memory[ prop ] === "undefined" ) {
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var ucProp = prop.charAt( 0 ).toUpperCase() + prop.substr( 1 ),
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props = ( prop + " " + prefixes.join( ucProp + " " ) + ucProp ).split( " " );
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memory[ prop ] = null;
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for ( var i in props ) {
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if ( style[ props[ i ] ] !== undefined ) {
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memory[ prop ] = props[ i ];
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break;
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}
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}
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}
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return memory[ prop ];
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};
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} )();
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var removeBlackout = function() {
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if ( blackedOut ) {
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css( canvas, {
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display: "block"
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} );
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blackedOut = false;
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}
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};
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var blackout = function() {
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if ( blackedOut ) {
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removeBlackout();
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} else {
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css( canvas, {
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display: ( blackedOut = !blackedOut ) ? "none" : "block"
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} );
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blackedOut = true;
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}
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};
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// Wait for impress.js to be initialized
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document.addEventListener( "impress:init", function( event ) {
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var api = event.detail.api;
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var root = event.target;
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canvas = root.firstElementChild;
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var gc = api.lib.gc;
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gc.addEventListener( document, "keydown", function( event ) {
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if ( event.ctrlKey && event.keyCode === 66 ) {
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event.preventDefault();
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if ( !blackedOut ) {
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blackout();
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} else {
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// Note: This doesn't work on Firefox. It will set display:block,
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// but slides only become visible again upon next transition, which
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// forces some kind of redraw. Works as intended on Chrome.
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removeBlackout();
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}
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}
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}, false );
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gc.addEventListener( document, "keyup", function( event ) {
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if ( event.ctrlKey && event.keyCode === 66 ) {
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event.preventDefault();
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}
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}, false );
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}, false );
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document.addEventListener( "impress:stepleave", function() {
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removeBlackout();
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}, false );
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} )( document );
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