plugin/zoom/plugin.js
/*!
* reveal.js Zoom plugin
*/
const Plugin = {
id: 'zoom',
init: function( reveal ) {
reveal.getRevealElement().addEventListener( 'mousedown', function( event ) {
var defaultModifier = /Linux/.test( window.navigator.platform ) ? 'ctrl' : 'alt';
var modifier = ( reveal.getConfig().zoomKey ? reveal.getConfig().zoomKey : defaultModifier ) + 'Key';
var zoomLevel = ( reveal.getConfig().zoomLevel ? reveal.getConfig().zoomLevel : 2 );
if( event[ modifier ] && !reveal.isOverview() ) {
event.preventDefault();
zoom.to({
x: event.clientX,
y: event.clientY,
scale: zoomLevel,
pan: false
});
}
} );
},
destroy: () => {
zoom.reset();
}
};
export default () => Plugin;
/*!
* zoom.js 0.3 (modified for use with reveal.js)
* http://lab.hakim.se/zoom-js
* MIT licensed
*
* Copyright (C) 2011-2014 Hakim El Hattab, http://hakim.se
*/
var zoom = (function(){
// The current zoom level (scale)
var level = 1;
// The current mouse position, used for panning
var mouseX = 0,
mouseY = 0;
// Timeout before pan is activated
var panEngageTimeout = -1,
panUpdateInterval = -1;
// Check for transform support so that we can fallback otherwise
var supportsTransforms = 'transform' in document.body.style;
if( supportsTransforms ) {
// The easing that will be applied when we zoom in/out
document.body.style.transition = 'transform 0.8s ease';
}
// Zoom out if the user hits escape
document.addEventListener( 'keyup', function( event ) {
if( level !== 1 && event.keyCode === 27 ) {
zoom.out();
}
} );
// Monitor mouse movement for panning
document.addEventListener( 'mousemove', function( event ) {
if( level !== 1 ) {
mouseX = event.clientX;
mouseY = event.clientY;
}
} );
/**
* Applies the CSS required to zoom in, prefers the use of CSS3
* transforms but falls back on zoom for IE.
*
* @param {Object} rect
* @param {Number} scale
*/
function magnify( rect, scale ) {
var scrollOffset = getScrollOffset();
// Ensure a width/height is set
rect.width = rect.width || 1;
rect.height = rect.height || 1;
// Center the rect within the zoomed viewport
rect.x -= ( window.innerWidth - ( rect.width * scale ) ) / 2;
rect.y -= ( window.innerHeight - ( rect.height * scale ) ) / 2;
if( supportsTransforms ) {
// Reset
if( scale === 1 ) {
document.body.style.transform = '';
}
// Scale
else {
var origin = scrollOffset.x +'px '+ scrollOffset.y +'px',
transform = 'translate('+ -rect.x +'px,'+ -rect.y +'px) scale('+ scale +')';
document.body.style.transformOrigin = origin;
document.body.style.transform = transform;
}
}
else {
// Reset
if( scale === 1 ) {
document.body.style.position = '';
document.body.style.left = '';
document.body.style.top = '';
document.body.style.width = '';
document.body.style.height = '';
document.body.style.zoom = '';
}
// Scale
else {
document.body.style.position = 'relative';
document.body.style.left = ( - ( scrollOffset.x + rect.x ) / scale ) + 'px';
document.body.style.top = ( - ( scrollOffset.y + rect.y ) / scale ) + 'px';
document.body.style.width = ( scale * 100 ) + '%';
document.body.style.height = ( scale * 100 ) + '%';
document.body.style.zoom = scale;
}
}
level = scale;
if( document.documentElement.classList ) {
if( level !== 1 ) {
document.documentElement.classList.add( 'zoomed' );
}
else {
document.documentElement.classList.remove( 'zoomed' );
}
}
}
/**
* Pan the document when the mosue cursor approaches the edges
* of the window.
*/
function pan() {
var range = 0.12,
rangeX = window.innerWidth * range,
rangeY = window.innerHeight * range,
scrollOffset = getScrollOffset();
// Up
if( mouseY < rangeY ) {
window.scroll( scrollOffset.x, scrollOffset.y - ( 1 - ( mouseY / rangeY ) ) * ( 14 / level ) );
}
// Down
else if( mouseY > window.innerHeight - rangeY ) {
window.scroll( scrollOffset.x, scrollOffset.y + ( 1 - ( window.innerHeight - mouseY ) / rangeY ) * ( 14 / level ) );
}
// Left
if( mouseX < rangeX ) {
window.scroll( scrollOffset.x - ( 1 - ( mouseX / rangeX ) ) * ( 14 / level ), scrollOffset.y );
}
// Right
else if( mouseX > window.innerWidth - rangeX ) {
window.scroll( scrollOffset.x + ( 1 - ( window.innerWidth - mouseX ) / rangeX ) * ( 14 / level ), scrollOffset.y );
}
}
function getScrollOffset() {
return {
x: window.scrollX !== undefined ? window.scrollX : window.pageXOffset,
y: window.scrollY !== undefined ? window.scrollY : window.pageYOffset
}
}
return {
/**
* Zooms in on either a rectangle or HTML element.
*
* @param {Object} options
* - element: HTML element to zoom in on
* OR
* - x/y: coordinates in non-transformed space to zoom in on
* - width/height: the portion of the screen to zoom in on
* - scale: can be used instead of width/height to explicitly set scale
*/
to: function( options ) {
// Due to an implementation limitation we can't zoom in
// to another element without zooming out first
if( level !== 1 ) {
zoom.out();
}
else {
options.x = options.x || 0;
options.y = options.y || 0;
// If an element is set, that takes precedence
if( !!options.element ) {
// Space around the zoomed in element to leave on screen
var padding = 20;
var bounds = options.element.getBoundingClientRect();
options.x = bounds.left - padding;
options.y = bounds.top - padding;
options.width = bounds.width + ( padding * 2 );
options.height = bounds.height + ( padding * 2 );
}
// If width/height values are set, calculate scale from those values
if( options.width !== undefined && options.height !== undefined ) {
options.scale = Math.max( Math.min( window.innerWidth / options.width, window.innerHeight / options.height ), 1 );
}
if( options.scale > 1 ) {
options.x *= options.scale;
options.y *= options.scale;
magnify( options, options.scale );
if( options.pan !== false ) {
// Wait with engaging panning as it may conflict with the
// zoom transition
panEngageTimeout = setTimeout( function() {
panUpdateInterval = setInterval( pan, 1000 / 60 );
}, 800 );
}
}
}
},
/**
* Resets the document zoom state to its default.
*/
out: function() {
clearTimeout( panEngageTimeout );
clearInterval( panUpdateInterval );
magnify( { x: 0, y: 0 }, 1 );
level = 1;
},
// Alias
magnify: function( options ) { this.to( options ) },
reset: function() { this.out() },
zoomLevel: function() {
return level;
}
}
})();