zoom.js integration via alt+click

1 files changed, 257 insertions, 0 deletions

diff --git a/lib/js/zoom.js b/lib/js/zoom.js
new file mode 100644
index 0000000..7fba523
--- /dev/null
+++ b/lib/js/zoom.js
@@ -0,0 +1,257 @@
+/*!
+ * zoom.js 0.2 (modified version for use with reveal.js)
+ * http://lab.hakim.se/zoom-js
+ * MIT licensed
+ * 
+ * Copyright (C) 2011-2012 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;
+
+	var currentOptions = null;
+
+	// Check for transform support so that we can fallback otherwise
+	var supportsTransforms = 	'WebkitTransform' in document.body.style ||
+								'MozTransform' in document.body.style ||
+								'msTransform' in document.body.style ||
+								'OTransform' in document.body.style ||
+								'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';
+		document.body.style.OTransition = '-o-transform 0.8s ease';
+		document.body.style.msTransition = '-ms-transform 0.8s ease';
+		document.body.style.MozTransition = '-moz-transform 0.8s ease';
+		document.body.style.WebkitTransition = '-webkit-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, prioritizes use of CSS3 
+	 * transforms but falls back on zoom for IE.
+	 * 
+	 * @param {Number} pageOffsetX 
+	 * @param {Number} pageOffsetY 
+	 * @param {Number} elementOffsetX 
+	 * @param {Number} elementOffsetY 
+	 * @param {Number} scale 
+	 */
+	function magnify( pageOffsetX, pageOffsetY, elementOffsetX, elementOffsetY, scale ) {
+
+		if( supportsTransforms ) {
+			var origin = pageOffsetX +'px '+ pageOffsetY +'px',
+				transform = 'translate('+ -elementOffsetX +'px,'+ -elementOffsetY +'px) scale('+ scale +')';
+			
+			document.body.style.transformOrigin = origin;
+			document.body.style.OTransformOrigin = origin;
+			document.body.style.msTransformOrigin = origin;
+			document.body.style.MozTransformOrigin = origin;
+			document.body.style.WebkitTransformOrigin = origin;
+
+			document.body.style.transform = transform;
+			document.body.style.OTransform = transform;
+			document.body.style.msTransform = transform;
+			document.body.style.MozTransform = transform;
+			document.body.style.WebkitTransform = transform;
+		}
+		else {
+			// Reset all values
+			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 = '';
+			}
+			// Apply scale
+			else {
+				document.body.style.position = 'relative';
+				document.body.style.left = ( - ( pageOffsetX + elementOffsetX ) / scale ) + 'px';
+				document.body.style.top = ( - ( pageOffsetY + elementOffsetY ) / scale ) + 'px';
+				document.body.style.width = ( scale * 100 ) + '%';
+				document.body.style.height = ( scale * 100 ) + '%';
+				document.body.style.zoom = scale;
+			}
+		}
+
+		level = scale;
+	}
+
+	/**
+	 * 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.pageXYffset
+		}
+	}
+
+	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;
+
+					options.width = options.element.getBoundingClientRect().width + ( padding * 2 );
+					options.height = options.element.getBoundingClientRect().height + ( padding * 2 );
+					options.x = options.element.getBoundingClientRect().left - padding;
+					options.y = options.element.getBoundingClientRect().top - padding;
+				}
+
+				// 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;
+
+					var scrollOffset = getScrollOffset();
+
+					if( options.element ) {
+						scrollOffset.x -= ( window.innerWidth - ( options.width * options.scale ) ) / 2;
+					}
+
+					magnify( scrollOffset.x, scrollOffset.y, options.x, options.y, 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 );
+
+					}
+				}
+
+				currentOptions = options;
+			}
+		},
+
+		/**
+		 * Resets the document zoom state to its default.
+		 */
+		out: function() {
+			clearTimeout( panEngageTimeout );
+			clearInterval( panUpdateInterval );
+
+			var scrollOffset = getScrollOffset();
+
+			if( currentOptions && currentOptions.element ) {
+				scrollOffset.x -= ( window.innerWidth - ( currentOptions.width * currentOptions.scale ) ) / 2;
+			}
+			
+			magnify( scrollOffset.x, scrollOffset.y, 0, 0, 1 );
+
+			level = 1;
+		},
+
+		// Alias
+		magnify: function( options ) { this.to( options ) },
+		reset: function() { this.out() },
+		
+		zoomLevel: function() {
+			return level;
+		}
+	}
+	
+})();
+
+
+
+
+// Custom reveal.js integration
+(function(){
+	var modifierIsActive = false;
+
+	function updateKeyFlag( event ) {
+		modifierIsActive = event.altKey;
+	}
+
+	document.addEventListener( 'keypress', updateKeyFlag, false );
+	document.addEventListener( 'keydown', updateKeyFlag, false );
+	document.addEventListener( 'keyup', updateKeyFlag, false );
+
+	document.querySelector( '.reveal' ).addEventListener( 'click', function( event ) {
+		if( modifierIsActive ) {
+			event.preventDefault();
+			zoom.to({ element: event.target, pan: false });
+		}
+	} );
+})();
+