import { queryAll } from '../utils/util.js' import { colorToRgb, colorBrightness } from '../utils/color.js' /** * Creates and updates slide backgrounds. */ export default class Backgrounds { constructor( Reveal ) { this.Reveal = Reveal; } render() { this.element = document.createElement( 'div' ); this.element.className = 'backgrounds'; this.Reveal.getRevealElement().appendChild( this.element ); } /** * Creates the slide background elements and appends them * to the background container. One element is created per * slide no matter if the given slide has visible background. */ create() { // Clear prior backgrounds this.element.innerHTML = ''; this.element.classList.add( 'no-transition' ); // Iterate over all horizontal slides this.Reveal.getHorizontalSlides().forEach( slideh => { let backgroundStack = this.createBackground( slideh, this.element ); // Iterate over all vertical slides queryAll( slideh, 'section' ).forEach( slidev => { this.createBackground( slidev, backgroundStack ); backgroundStack.classList.add( 'stack' ); } ); } ); // Add parallax background if specified if( this.Reveal.getConfig().parallaxBackgroundImage ) { this.element.style.backgroundImage = 'url("' + this.Reveal.getConfig().parallaxBackgroundImage + '")'; this.element.style.backgroundSize = this.Reveal.getConfig().parallaxBackgroundSize; this.element.style.backgroundRepeat = this.Reveal.getConfig().parallaxBackgroundRepeat; this.element.style.backgroundPosition = this.Reveal.getConfig().parallaxBackgroundPosition; // Make sure the below properties are set on the element - these properties are // needed for proper transitions to be set on the element via CSS. To remove // annoying background slide-in effect when the presentation starts, apply // these properties after short time delay setTimeout( () => { this.Reveal.getRevealElement().classList.add( 'has-parallax-background' ); }, 1 ); } else { this.element.style.backgroundImage = ''; this.Reveal.getRevealElement().classList.remove( 'has-parallax-background' ); } } /** * Creates a background for the given slide. * * @param {HTMLElement} slide * @param {HTMLElement} container The element that the background * should be appended to * @return {HTMLElement} New background div */ createBackground( slide, container ) { // Main slide background element let element = document.createElement( 'div' ); element.className = 'slide-background ' + slide.className.replace( /present|past|future/, '' ); // Inner background element that wraps images/videos/iframes let contentElement = document.createElement( 'div' ); contentElement.className = 'slide-background-content'; element.appendChild( contentElement ); container.appendChild( element ); slide.slideBackgroundElement = element; slide.slideBackgroundContentElement = contentElement; // Syncs the background to reflect all current background settings this.sync( slide ); return element; } /** * Renders all of the visual properties of a slide background * based on the various background attributes. * * @param {HTMLElement} slide */ sync( slide ) { const element = slide.slideBackgroundElement, contentElement = slide.slideBackgroundContentElement; const data = { background: slide.getAttribute( 'data-background' ), backgroundSize: slide.getAttribute( 'data-background-size' ), backgroundImage: slide.getAttribute( 'data-background-image' ), backgroundVideo: slide.getAttribute( 'data-background-video' ), backgroundIframe: slide.getAttribute( 'data-background-iframe' ), backgroundColor: slide.getAttribute( 'data-background-color' ), backgroundGradient: slide.getAttribute( 'data-background-gradient' ), backgroundRepeat: slide.getAttribute( 'data-background-repeat' ), backgroundPosition: slide.getAttribute( 'data-background-position' ), backgroundTransition: slide.getAttribute( 'data-background-transition' ), backgroundOpacity: slide.getAttribute( 'data-background-opacity' ), }; const dataPreload = slide.hasAttribute( 'data-preload' ); // Reset the prior background state in case this is not the // initial sync slide.classList.remove( 'has-dark-background' ); slide.classList.remove( 'has-light-background' ); element.removeAttribute( 'data-loaded' ); element.removeAttribute( 'data-background-hash' ); element.removeAttribute( 'data-background-size' ); element.removeAttribute( 'data-background-transition' ); element.style.backgroundColor = ''; contentElement.style.backgroundSize = ''; contentElement.style.backgroundRepeat = ''; contentElement.style.backgroundPosition = ''; contentElement.style.backgroundImage = ''; contentElement.style.opacity = ''; contentElement.innerHTML = ''; if( data.background ) { // Auto-wrap image urls in url(...) if( /^(http|file|\/\/)/gi.test( data.background ) || /\.(svg|png|jpg|jpeg|gif|bmp|webp)([?#\s]|$)/gi.test( data.background ) ) { slide.setAttribute( 'data-background-image', data.background ); } else { element.style.background = data.background; } } // Create a hash for this combination of background settings. // This is used to determine when two slide backgrounds are // the same. if( data.background || data.backgroundColor || data.backgroundGradient || data.backgroundImage || data.backgroundVideo || data.backgroundIframe ) { element.setAttribute( 'data-background-hash', data.background + data.backgroundSize + data.backgroundImage + data.backgroundVideo + data.backgroundIframe + data.backgroundColor + data.backgroundGradient + data.backgroundRepeat + data.backgroundPosition + data.backgroundTransition + data.backgroundOpacity ); } // Additional and optional background properties if( data.backgroundSize ) element.setAttribute( 'data-background-size', data.backgroundSize ); if( data.backgroundColor ) element.style.backgroundColor = data.backgroundColor; if( data.backgroundGradient ) element.style.backgroundImage = data.backgroundGradient; if( data.backgroundTransition ) element.setAttribute( 'data-background-transition', data.backgroundTransition ); if( dataPreload ) element.setAttribute( 'data-preload', '' ); // Background image options are set on the content wrapper if( data.backgroundSize ) contentElement.style.backgroundSize = data.backgroundSize; if( data.backgroundRepeat ) contentElement.style.backgroundRepeat = data.backgroundRepeat; if( data.backgroundPosition ) contentElement.style.backgroundPosition = data.backgroundPosition; if( data.backgroundOpacity ) contentElement.style.opacity = data.backgroundOpacity; const contrastClass = this.getContrastClass( slide ); if( typeof contrastClass === 'string' ) { slide.classList.add( contrastClass ); } } /** * Returns a class name that can be applied to a slide to indicate * if it has a light or dark background. * * @param {*} slide * * @returns {string|null} */ getContrastClass( slide ) { const element = slide.slideBackgroundElement; // If this slide has a background color, we add a class that // signals if it is light or dark. If the slide has no background // color, no class will be added let contrastColor = slide.getAttribute( 'data-background-color' ); // If no bg color was found, or it cannot be converted by colorToRgb, check the computed background if( !contrastColor || !colorToRgb( contrastColor ) ) { let computedBackgroundStyle = window.getComputedStyle( element ); if( computedBackgroundStyle && computedBackgroundStyle.backgroundColor ) { contrastColor = computedBackgroundStyle.backgroundColor; } } if( contrastColor ) { const rgb = colorToRgb( contrastColor ); // Ignore fully transparent backgrounds. Some browsers return // rgba(0,0,0,0) when reading the computed background color of // an element with no background if( rgb && rgb.a !== 0 ) { if( colorBrightness( contrastColor ) < 128 ) { return 'has-dark-background'; } else { return 'has-light-background'; } } } return null; } /** * Bubble the 'has-light-background'/'has-dark-background' classes. */ bubbleSlideContrastClassToElement( slide, target ) { [ 'has-light-background', 'has-dark-background' ].forEach( classToBubble => { if( slide.classList.contains( classToBubble ) ) { target.classList.add( classToBubble ); } else { target.classList.remove( classToBubble ); } }, this ); } /** * Updates the background elements to reflect the current * slide. * * @param {boolean} includeAll If true, the backgrounds of * all vertical slides (not just the present) will be updated. */ update( includeAll = false ) { let config = this.Reveal.getConfig(); let currentSlide = this.Reveal.getCurrentSlide(); let indices = this.Reveal.getIndices(); let currentBackground = null; // Reverse past/future classes when in RTL mode let horizontalPast = config.rtl ? 'future' : 'past', horizontalFuture = config.rtl ? 'past' : 'future'; // Update the classes of all backgrounds to match the // states of their slides (past/present/future) Array.from( this.element.childNodes ).forEach( ( backgroundh, h ) => { backgroundh.classList.remove( 'past', 'present', 'future' ); if( h < indices.h ) { backgroundh.classList.add( horizontalPast ); } else if ( h > indices.h ) { backgroundh.classList.add( horizontalFuture ); } else { backgroundh.classList.add( 'present' ); // Store a reference to the current background element currentBackground = backgroundh; } if( includeAll || h === indices.h ) { queryAll( backgroundh, '.slide-background' ).forEach( ( backgroundv, v ) => { backgroundv.classList.remove( 'past', 'present', 'future' ); const indexv = typeof indices.v === 'number' ? indices.v : 0; if( v < indexv ) { backgroundv.classList.add( 'past' ); } else if ( v > indexv ) { backgroundv.classList.add( 'future' ); } else { backgroundv.classList.add( 'present' ); // Only if this is the present horizontal and vertical slide if( h === indices.h ) currentBackground = backgroundv; } } ); } } ); // The previous background may refer to a DOM element that has // been removed after a presentation is synced & bgs are recreated if( this.previousBackground && !this.previousBackground.closest( 'body' ) ) { this.previousBackground = null; } if( currentBackground && this.previousBackground ) { // Don't transition between identical backgrounds. This // prevents unwanted flicker. let previousBackgroundHash = this.previousBackground.getAttribute( 'data-background-hash' ); let currentBackgroundHash = currentBackground.getAttribute( 'data-background-hash' ); if( currentBackgroundHash && currentBackgroundHash === previousBackgroundHash && currentBackground !== this.previousBackground ) { this.element.classList.add( 'no-transition' ); // If multiple slides have the same background video, carry // the