in js/reveal.js [559:620]
toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR ) ).forEach( function( slide ) {
// Vertical stacks are not centred since their section
// children will be
if( slide.classList.contains( 'stack' ) === false ) {
// Center the slide inside of the page, giving the slide some margin
var left = ( pageWidth - slideWidth ) / 2,
top = ( pageHeight - slideHeight ) / 2;
var contentHeight = getAbsoluteHeight( slide );
var numberOfPages = Math.max( Math.ceil( contentHeight / pageHeight ), 1 );
// Center slides vertically
if( numberOfPages === 1 && config.center || slide.classList.contains( 'center' ) ) {
top = Math.max( ( pageHeight - contentHeight ) / 2, 0 );
}
// Position the slide inside of the page
slide.style.left = left + 'px';
slide.style.top = top + 'px';
slide.style.width = slideWidth + 'px';
// TODO Backgrounds need to be multiplied when the slide
// stretches over multiple pages
var background = slide.querySelector( '.slide-background' );
if( background ) {
background.style.width = pageWidth + 'px';
background.style.height = ( pageHeight * numberOfPages ) + 'px';
background.style.top = -top + 'px';
background.style.left = -left + 'px';
}
// Inject notes if `showNotes` is enabled
if( config.showNotes ) {
var notes = getSlideNotes( slide );
if( notes ) {
var notesSpacing = 8;
var notesElement = document.createElement( 'div' );
notesElement.classList.add( 'speaker-notes' );
notesElement.classList.add( 'speaker-notes-pdf' );
notesElement.innerHTML = notes;
notesElement.style.left = ( notesSpacing - left ) + 'px';
notesElement.style.bottom = ( notesSpacing - top ) + 'px';
notesElement.style.width = ( pageWidth - notesSpacing*2 ) + 'px';
slide.appendChild( notesElement );
}
}
// Inject slide numbers if `slideNumbers` are enabled
if( config.slideNumber ) {
var slideNumberH = parseInt( slide.getAttribute( 'data-index-h' ), 10 ) + 1,
slideNumberV = parseInt( slide.getAttribute( 'data-index-v' ), 10 ) + 1;
var numberElement = document.createElement( 'div' );
numberElement.classList.add( 'slide-number' );
numberElement.classList.add( 'slide-number-pdf' );
numberElement.innerHTML = formatSlideNumber( slideNumberH, '.', slideNumberV );
background.appendChild( numberElement );
}
}
} );