magnific-popup/src/js/zoom.js

Lightbox and modal dialog plugin. Can display inline HTML, iframes (YouTube video, Vimeo, Google Maps), or an image gallery. Animation effects are added with CSS3 transitions. For jQuery or Zepto.

var hasMozTransform,
	getHasMozTransform = function() {
		if(hasMozTransform === undefined) {
			hasMozTransform = document.createElement('p').style.MozTransform !== undefined;
		}
		return hasMozTransform;
	};

$.magnificPopup.registerModule('zoom', {

	options: {
		enabled: false,
		easing: 'ease-in-out',
		duration: 300,
		opener: function(element) {
			return element.is('img') ? element : element.find('img');
		}
	},

	proto: {

		initZoom: function() {
			var zoomSt = mfp.st.zoom,
				ns = '.zoom',
				image;

			if(!zoomSt.enabled || !mfp.supportsTransition) {
				return;
			}

			var duration = zoomSt.duration,
				getElToAnimate = function(image) {
					var newImg = image.clone().removeAttr('style').removeAttr('class').addClass('mfp-animated-image'),
						transition = 'all '+(zoomSt.duration/1000)+'s ' + zoomSt.easing,
						cssObj = {
							position: 'fixed',
							zIndex: 9999,
							left: 0,
							top: 0,
							'-webkit-backface-visibility': 'hidden'
						},
						t = 'transition';

					cssObj['-webkit-'+t] = cssObj['-moz-'+t] = cssObj['-o-'+t] = cssObj[t] = transition;

					newImg.css(cssObj);
					return newImg;
				},
				showMainContent = function() {
					mfp.content.css('visibility', 'visible');
				},
				openTimeout,
				animatedImg;

			_mfpOn('BuildControls'+ns, function() {
				if(mfp._allowZoom()) {

					clearTimeout(openTimeout);
					mfp.content.css('visibility', 'hidden');

					// Basically, all code below does is clones existing image, puts in on top of the current one and animated it

					image = mfp._getItemToZoom();

					if(!image) {
						showMainContent();
						return;
					}

					animatedImg = getElToAnimate(image);

					animatedImg.css( mfp._getOffset() );

					mfp.wrap.append(animatedImg);

					openTimeout = setTimeout(function() {
						animatedImg.css( mfp._getOffset( true ) );
						openTimeout = setTimeout(function() {

							showMainContent();

							setTimeout(function() {
								animatedImg.remove();
								image = animatedImg = null;
								_mfpTrigger('ZoomAnimationEnded');
							}, 16); // avoid blink when switching images

						}, duration); // this timeout equals animation duration

					}, 16); // by adding this timeout we avoid short glitch at the beginning of animation


					// Lots of timeouts...
				}
			});
			_mfpOn(BEFORE_CLOSE_EVENT+ns, function() {
				if(mfp._allowZoom()) {

					clearTimeout(openTimeout);

					mfp.st.removalDelay = duration;

					if(!image) {
						image = mfp._getItemToZoom();
						if(!image) {
							return;
						}
						animatedImg = getElToAnimate(image);
					}

					animatedImg.css( mfp._getOffset(true) );
					mfp.wrap.append(animatedImg);
					mfp.content.css('visibility', 'hidden');

					setTimeout(function() {
						animatedImg.css( mfp._getOffset() );
					}, 16);
				}

			});

			_mfpOn(CLOSE_EVENT+ns, function() {
				if(mfp._allowZoom()) {
					showMainContent();
					if(animatedImg) {
						animatedImg.remove();
					}
					image = null;
				}
			});
		},

		_allowZoom: function() {
			return mfp.currItem.type === 'image';
		},

		_getItemToZoom: function() {
			if(mfp.currItem.hasSize) {
				return mfp.currItem.img;
			} else {
				return false;
			}
		},

		// Get element postion relative to viewport
		_getOffset: function(isLarge) {
			var el;
			if(isLarge) {
				el = mfp.currItem.img;
			} else {
				el = mfp.st.zoom.opener(mfp.currItem.el || mfp.currItem);
			}

			var offset = el.offset();
			var paddingTop = parseInt(el.css('padding-top'),10);
			var paddingBottom = parseInt(el.css('padding-bottom'),10);
			offset.top -= ( $(window).scrollTop() - paddingTop );


			/*

			Animating left + top + width/height looks glitchy in Firefox, but perfect in Chrome. And vice-versa.

			 */
			var obj = {
				width: el.width(),
				// fix Zepto height+padding issue
				height: (_isJQ ? el.innerHeight() : el[0].offsetHeight) - paddingBottom - paddingTop
			};

			// I hate to do this, but there is no another option
			if( getHasMozTransform() ) {
				obj['-moz-transform'] = obj['transform'] = 'translate(' + offset.left + 'px,' + offset.top + 'px)';
			} else {
				obj.left = offset.left;
				obj.top = offset.top;
			}
			return obj;
		}

	}
});