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