function configure()

in js/reveal.js [1293:1458]

• 114 lines of code
• 30 McCabe index (conditional complexity)

	function configure( options ) {

		var oldTransition = config.transition;

		// New config options may be passed when this method
		// is invoked through the API after initialization
		if( typeof options === 'object' ) extend( config, options );

		// Abort if reveal.js hasn't finished loading, config
		// changes will be applied automatically once loading
		// finishes
		if( loaded === false ) return;

		var numberOfSlides = dom.wrapper.querySelectorAll( SLIDES_SELECTOR ).length;

		// Remove the previously configured transition class
		dom.wrapper.classList.remove( oldTransition );

		// Force linear transition based on browser capabilities
		if( features.transforms3d === false ) config.transition = 'linear';

		dom.wrapper.classList.add( config.transition );

		dom.wrapper.setAttribute( 'data-transition-speed', config.transitionSpeed );
		dom.wrapper.setAttribute( 'data-background-transition', config.backgroundTransition );

		dom.controls.style.display = config.controls ? 'block' : 'none';
		dom.progress.style.display = config.progress ? 'block' : 'none';

		dom.controls.setAttribute( 'data-controls-layout', config.controlsLayout );
		dom.controls.setAttribute( 'data-controls-back-arrows', config.controlsBackArrows );

		if( config.shuffle ) {
			shuffle();
		}

		if( config.rtl ) {
			dom.wrapper.classList.add( 'rtl' );
		}
		else {
			dom.wrapper.classList.remove( 'rtl' );
		}

		if( config.center ) {
			dom.wrapper.classList.add( 'center' );
		}
		else {
			dom.wrapper.classList.remove( 'center' );
		}

		// Exit the paused mode if it was configured off
		if( config.pause === false ) {
			resume();
		}

		if( config.showNotes ) {
			dom.speakerNotes.setAttribute( 'data-layout', typeof config.showNotes === 'string' ? config.showNotes : 'inline' );
		}

		if( config.mouseWheel ) {
			document.addEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
			document.addEventListener( 'mousewheel', onDocumentMouseScroll, false );
		}
		else {
			document.removeEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
			document.removeEventListener( 'mousewheel', onDocumentMouseScroll, false );
		}

		// Rolling 3D links
		if( config.rollingLinks ) {
			enableRollingLinks();
		}
		else {
			disableRollingLinks();
		}

		// Auto-hide the mouse pointer when its inactive
		if( config.hideInactiveCursor ) {
			document.addEventListener( 'mousemove', onDocumentCursorActive, false );
			document.addEventListener( 'mousedown', onDocumentCursorActive, false );
		}
		else {
			showCursor();

			document.removeEventListener( 'mousemove', onDocumentCursorActive, false );
			document.removeEventListener( 'mousedown', onDocumentCursorActive, false );
		}

		// Iframe link previews
		if( config.previewLinks ) {
			enablePreviewLinks();
			disablePreviewLinks( '[data-preview-link=false]' );
		}
		else {
			disablePreviewLinks();
			enablePreviewLinks( '[data-preview-link]:not([data-preview-link=false])' );
		}

		// Remove existing auto-slide controls
		if( autoSlidePlayer ) {
			autoSlidePlayer.destroy();
			autoSlidePlayer = null;
		}

		// Generate auto-slide controls if needed
		if( numberOfSlides > 1 && config.autoSlide && config.autoSlideStoppable && features.canvas && features.requestAnimationFrame ) {
			autoSlidePlayer = new Playback( dom.wrapper, function() {
				return Math.min( Math.max( ( Date.now() - autoSlideStartTime ) / autoSlide, 0 ), 1 );
			} );

			autoSlidePlayer.on( 'click', onAutoSlidePlayerClick );
			autoSlidePaused = false;
		}

		// When fragments are turned off they should be visible
		if( config.fragments === false ) {
			toArray( dom.slides.querySelectorAll( '.fragment' ) ).forEach( function( element ) {
				element.classList.add( 'visible' );
				element.classList.remove( 'current-fragment' );
			} );
		}

		// Slide numbers
		var slideNumberDisplay = 'none';
		if( config.slideNumber && !isPrintingPDF() ) {
			if( config.showSlideNumber === 'all' ) {
				slideNumberDisplay = 'block';
			}
			else if( config.showSlideNumber === 'speaker' && isSpeakerNotes() ) {
				slideNumberDisplay = 'block';
			}
		}

		dom.slideNumber.style.display = slideNumberDisplay;

		// Add the navigation mode to the DOM so we can adjust styling
		if( config.navigationMode !== 'default' ) {
			dom.wrapper.setAttribute( 'data-navigation-mode', config.navigationMode );
		}
		else {
			dom.wrapper.removeAttribute( 'data-navigation-mode' );
		}

		// Define our contextual list of keyboard shortcuts
		if( config.navigationMode === 'linear' ) {
			keyboardShortcuts['→  ,  ↓  ,  SPACE  ,  N  ,  L  ,  J'] = 'Next slide';
			keyboardShortcuts['←  ,  ↑  ,  P  ,  H  ,  K']           = 'Previous slide';
		}
		else {
			keyboardShortcuts['N  ,  SPACE']   = 'Next slide';
			keyboardShortcuts['P']             = 'Previous slide';
			keyboardShortcuts['←  ,  H'] = 'Navigate left';
			keyboardShortcuts['→  ,  L'] = 'Navigate right';
			keyboardShortcuts['↑  ,  K'] = 'Navigate up';
			keyboardShortcuts['↓  ,  J'] = 'Navigate down';
		}

		keyboardShortcuts['Home  ,  ⌘/CTRL ←'] = 'First slide';
		keyboardShortcuts['End  ,  ⌘/CTRL →']  = 'Last slide';
		keyboardShortcuts['B  ,  .']                       = 'Pause';
		keyboardShortcuts['F']                             = 'Fullscreen';
		keyboardShortcuts['ESC, O']                        = 'Slide overview';

		sync();

	}