diff --git a/dist/pinch-zoom.min.js b/dist/pinch-zoom.min.js
index 26daab0..93edec4 100644
--- a/dist/pinch-zoom.min.js
+++ b/dist/pinch-zoom.min.js
@@ -1 +1 @@
-"function"!=typeof Object.assign&&Object.defineProperty(Object,"assign",{value:function(t,i){if(null==t)throw new TypeError("Cannot convert undefined or null to object");for(var e=Object(t),n=1;n<arguments.length;n++){var o=arguments[n];if(null!=o)for(var s in o)Object.prototype.hasOwnProperty.call(o,s)&&(e[s]=o[s])}return e},writable:!0,configurable:!0}),"function"!=typeof Array.from&&(Array.from=function(t){return[].slice.call(t)});var buildElement=function(t){var i=document.implementation.createHTMLDocument("");return i.body.innerHTML=t,Array.from(i.body.children)[0]},triggerEvent=function(t,i){var e=document.createEvent("HTMLEvents");e.initEvent(i,!0,!1),t.dispatchEvent(e)},definePinchZoom=function(){var t=function(t,i){this.el=t,this.zoomFactor=1,this.lastScale=1,this.offset={x:0,y:0},this.initialOffset={x:0,y:0},this.options=Object.assign({},this.defaults,i),this.setupMarkup(),this.bindEvents(),this.update(),this.isImageLoaded(this.el)&&(this.updateAspectRatio(),this.setupOffsets()),this.enable()},i=function(t,i){return t+i};t.prototype={defaults:{tapZoomFactor:2,zoomOutFactor:1.3,animationDuration:300,maxZoom:4,minZoom:.5,draggableUnzoomed:!0,lockDragAxis:!1,setOffsetsOnce:!1,use2d:!0,zoomStartEventName:"pz_zoomstart",zoomUpdateEventName:"pz_zoomupdate",zoomEndEventName:"pz_zoomend",dragStartEventName:"pz_dragstart",dragUpdateEventName:"pz_dragupdate",dragEndEventName:"pz_dragend",doubleTapEventName:"pz_doubletap",verticalPadding:0,horizontalPadding:0,onZoomStart:null,onZoomEnd:null,onZoomUpdate:null,onDragStart:null,onDragEnd:null,onDragUpdate:null,onDoubleTap:null},handleDragStart:function(t){triggerEvent(this.el,this.options.dragStartEventName),"function"==typeof this.options.onDragStart&&this.options.onDragStart(this,t),this.stopAnimation(),this.lastDragPosition=!1,this.hasInteraction=!0,this.handleDrag(t)},handleDrag:function(t){var i=this.getTouches(t)[0];this.drag(i,this.lastDragPosition),this.offset=this.sanitizeOffset(this.offset),this.lastDragPosition=i},handleDragEnd:function(){triggerEvent(this.el,this.options.dragEndEventName),"function"==typeof this.options.onDragEnd&&this.options.onDragEnd(this,event),this.end()},handleZoomStart:function(t){triggerEvent(this.el,this.options.zoomStartEventName),"function"==typeof this.options.onZoomStart&&this.options.onZoomStart(this,t),this.stopAnimation(),this.lastScale=1,this.nthZoom=0,this.lastZoomCenter=!1,this.hasInteraction=!0},handleZoom:function(t,i){var e=this.getTouchCenter(this.getTouches(t)),n=i/this.lastScale;this.lastScale=i,this.nthZoom+=1,this.nthZoom>3&&(this.scale(n,e),this.drag(e,this.lastZoomCenter)),this.lastZoomCenter=e},handleZoomEnd:function(){triggerEvent(this.el,this.options.zoomEndEventName),"function"==typeof this.options.onZoomEnd&&this.options.onZoomEnd(this,event),this.end()},handleDoubleTap:function(t){var i=this.getTouches(t)[0],e=this.zoomFactor>1?1:this.options.tapZoomFactor,n=this.zoomFactor,o=function(t){this.scaleTo(n+t*(e-n),i)}.bind(this);this.hasInteraction||(this.isDoubleTap=!0,n>e&&(i=this.getCurrentZoomCenter()),this.animate(this.options.animationDuration,o,this.swing),triggerEvent(this.el,this.options.doubleTapEventName),"function"==typeof this.options.onDoubleTap&&this.options.onDoubleTap(this,t))},computeInitialOffset:function(){this.initialOffset={x:-Math.abs(this.el.offsetWidth*this.getInitialZoomFactor()-this.container.offsetWidth)/2,y:-Math.abs(this.el.offsetHeight*this.getInitialZoomFactor()-this.container.offsetHeight)/2}},resetOffset:function(){this.offset.x=this.initialOffset.x,this.offset.y=this.initialOffset.y},isImageLoaded:function(t){return"IMG"===t.nodeName?t.complete&&0!==t.naturalHeight:Array.from(t.querySelectorAll("img")).every(this.isImageLoaded)},setupOffsets:function(){this.options.setOffsetsOnce&&this._isOffsetsSet||(this._isOffsetsSet=!0,this.computeInitialOffset(),this.resetOffset())},sanitizeOffset:function(t){var i=this.el.offsetWidth*this.getInitialZoomFactor()*this.zoomFactor,e=this.el.offsetHeight*this.getInitialZoomFactor()*this.zoomFactor,n=i-this.getContainerX()+this.options.horizontalPadding,o=e-this.getContainerY()+this.options.verticalPadding,s=Math.max(n,0),a=Math.max(o,0),h=Math.min(n,0)-this.options.horizontalPadding,r=Math.min(o,0)-this.options.verticalPadding;return{x:Math.min(Math.max(t.x,h),s),y:Math.min(Math.max(t.y,r),a)}},scaleTo:function(t,i){this.scale(t/this.zoomFactor,i)},scale:function(t,i){t=this.scaleZoomFactor(t),this.addOffset({x:(t-1)*(i.x+this.offset.x),y:(t-1)*(i.y+this.offset.y)}),triggerEvent(this.el,this.options.zoomUpdateEventName),"function"==typeof this.options.onZoomUpdate&&this.options.onZoomUpdate(this,event)},scaleZoomFactor:function(t){var i=this.zoomFactor;return this.zoomFactor*=t,this.zoomFactor=Math.min(this.options.maxZoom,Math.max(this.zoomFactor,this.options.minZoom)),this.zoomFactor/i},canDrag:function(){return this.options.draggableUnzoomed||!((t=this.zoomFactor)>(i=1)-.01&&t<i+.01);var t,i},drag:function(t,i){i&&(this.options.lockDragAxis?Math.abs(t.x-i.x)>Math.abs(t.y-i.y)?this.addOffset({x:-(t.x-i.x),y:0}):this.addOffset({y:-(t.y-i.y),x:0}):this.addOffset({y:-(t.y-i.y),x:-(t.x-i.x)}),triggerEvent(this.el,this.options.dragUpdateEventName),"function"==typeof this.options.onDragUpdate&&this.options.onDragUpdate(this,event))},getTouchCenter:function(t){return this.getVectorAvg(t)},getVectorAvg:function(t){return{x:t.map(function(t){return t.x}).reduce(i)/t.length,y:t.map(function(t){return t.y}).reduce(i)/t.length}},addOffset:function(t){this.offset={x:this.offset.x+t.x,y:this.offset.y+t.y}},sanitize:function(){this.zoomFactor<this.options.zoomOutFactor?this.zoomOutAnimation():this.isInsaneOffset(this.offset)&&this.sanitizeOffsetAnimation()},isInsaneOffset:function(t){var i=this.sanitizeOffset(t);return i.x!==t.x||i.y!==t.y},sanitizeOffsetAnimation:function(){var t=this.sanitizeOffset(this.offset),i=this.offset.x,e=this.offset.y,n=function(n){this.offset.x=i+n*(t.x-i),this.offset.y=e+n*(t.y-e),this.update()}.bind(this);this.animate(this.options.animationDuration,n,this.swing)},zoomOutAnimation:function(){if(1!==this.zoomFactor){var t=this.zoomFactor,i=this.getCurrentZoomCenter(),e=function(e){this.scaleTo(t+e*(1-t),i)}.bind(this);this.animate(this.options.animationDuration,e,this.swing)}},updateAspectRatio:function(){this.unsetContainerY(),this.setContainerY(this.container.parentElement.offsetHeight)},getInitialZoomFactor:function(){var t=this.container.offsetWidth/this.el.offsetWidth,i=this.container.offsetHeight/this.el.offsetHeight;return Math.min(t,i)},getAspectRatio:function(){return this.el.offsetWidth/this.el.offsetHeight},getCurrentZoomCenter:function(){var t=this.offset.x-this.initialOffset.x,i=-1*this.offset.x-t/(1/this.zoomFactor-1),e=this.offset.y-this.initialOffset.y;return{x:i,y:-1*this.offset.y-e/(1/this.zoomFactor-1)}},getTouches:function(t){var i=this.container.getBoundingClientRect(),e=document.documentElement.scrollTop||document.body.scrollTop,n=document.documentElement.scrollLeft||document.body.scrollLeft,o=i.top+e,s=i.left+n;return Array.prototype.slice.call(t.touches).map(function(t){return{x:t.pageX-s,y:t.pageY-o}})},animate:function(t,i,e,n){var o=(new Date).getTime(),s=function(){if(this.inAnimation){var a=(new Date).getTime()-o,h=a/t;a>=t?(i(1),n&&n(),this.update(),this.stopAnimation(),this.update()):(e&&(h=e(h)),i(h),this.update(),requestAnimationFrame(s))}}.bind(this);this.inAnimation=!0,requestAnimationFrame(s)},stopAnimation:function(){this.inAnimation=!1},swing:function(t){return-Math.cos(t*Math.PI)/2+.5},getContainerX:function(){return this.container.offsetWidth},getContainerY:function(){return this.container.offsetHeight},setContainerY:function(t){return this.container.style.height=t+"px"},unsetContainerY:function(){this.container.style.height=null},setupMarkup:function(){this.container=buildElement('<div class="pinch-zoom-container"></div>'),this.el.parentNode.insertBefore(this.container,this.el),this.container.appendChild(this.el),this.container.style.overflow="hidden",this.container.style.position="relative",this.el.style.webkitTransformOrigin="0% 0%",this.el.style.mozTransformOrigin="0% 0%",this.el.style.msTransformOrigin="0% 0%",this.el.style.oTransformOrigin="0% 0%",this.el.style.transformOrigin="0% 0%",this.el.style.position="absolute"},end:function(){this.hasInteraction=!1,this.sanitize(),this.update()},bindEvents:function(){var t=this;e(this.container,this),window.addEventListener("resize",this.update.bind(this)),Array.from(this.el.querySelectorAll("img")).forEach(function(i){i.addEventListener("load",t.update.bind(t))}),"IMG"===this.el.nodeName&&this.el.addEventListener("load",this.update.bind(this))},update:function(t){this.updatePlaned||(this.updatePlaned=!0,window.setTimeout(function(){this.updatePlaned=!1,t&&"resize"===t.type&&(this.updateAspectRatio(),this.setupOffsets()),t&&"load"===t.type&&(this.updateAspectRatio(),this.setupOffsets());var i=this.getInitialZoomFactor()*this.zoomFactor,e=-this.offset.x/i,n=-this.offset.y/i,o="scale3d("+i+", "+i+",1) translate3d("+e+"px,"+n+"px,0px)",s="scale("+i+", "+i+") translate("+e+"px,"+n+"px)",a=function(){this.clone&&(this.clone.parentNode.removeChild(this.clone),delete this.clone)}.bind(this);!this.options.use2d||this.hasInteraction||this.inAnimation?(this.is3d=!0,a(),this.el.style.webkitTransform=o,this.el.style.mozTransform=s,this.el.style.msTransform=s,this.el.style.oTransform=s,this.el.style.transform=o):(this.is3d&&(this.clone=this.el.cloneNode(!0),this.clone.style.pointerEvents="none",this.container.appendChild(this.clone),window.setTimeout(a,200)),this.el.style.webkitTransform=s,this.el.style.mozTransform=s,this.el.style.msTransform=s,this.el.style.oTransform=s,this.el.style.transform=s,this.is3d=!1)}.bind(this),0))},enable:function(){this.enabled=!0},disable:function(){this.enabled=!1}};var e=function(t,i){var e=null,n=0,o=null,s=null,a=function(t,n){if(e!==t){if(e&&!t)switch(e){case"zoom":i.handleZoomEnd(n);break;case"drag":i.handleDragEnd(n)}switch(t){case"zoom":i.handleZoomStart(n);break;case"drag":i.handleDragStart(n)}}e=t},h=function(t){2===n?a("zoom"):1===n&&i.canDrag()?a("drag",t):a(null,t)},r=function(t){return Array.from(t).map(function(t){return{x:t.pageX,y:t.pageY}})},f=function(t,i){var e,n;return e=t.x-i.x,n=t.y-i.y,Math.sqrt(e*e+n*n)},l=function(t){t.stopPropagation(),t.preventDefault()},c=!0;t.addEventListener("touchstart",function(t){i.enabled&&(c=!0,n=t.touches.length,function(t){var s=(new Date).getTime();if(n>1&&(o=null),s-o<300)switch(l(t),i.handleDoubleTap(t),e){case"zoom":i.handleZoomEnd(t);break;case"drag":i.handleDragEnd(t)}else i.isDoubleTap=!1;1===n&&(o=s)}(t))}),t.addEventListener("touchmove",function(t){if(i.enabled&&!i.isDoubleTap){if(c)h(t),e&&l(t),s=r(t.touches);else{switch(e){case"zoom":i.handleZoom(t,(n=s,o=r(t.touches),a=f(n[0],n[1]),f(o[0],o[1])/a));break;case"drag":i.handleDrag(t)}e&&(l(t),i.update())}c=!1}var n,o,a}),t.addEventListener("touchend",function(t){i.enabled&&(n=t.touches.length,h(t))})};return t},PinchZoom=definePinchZoom();export default PinchZoom;
\ No newline at end of file
+"function"!=typeof Object.assign&&Object.defineProperty(Object,"assign",{value:function(a){if(null==a)throw new TypeError("Cannot convert undefined or null to object");for(var b,c=Object(a),d=1;d<arguments.length;d++)if(b=arguments[d],null!=b)for(var e in b)Object.prototype.hasOwnProperty.call(b,e)&&(c[e]=b[e]);return c},writable:!0,configurable:!0}),"function"!=typeof Array.from&&(Array.from=function(a){return[].slice.call(a)});var buildElement=function(a){var b=document.implementation.createHTMLDocument("");return b.body.innerHTML=a,Array.from(b.body.children)[0]},triggerEvent=function(a,b){var c=document.createEvent("HTMLEvents");c.initEvent(b,!0,!1),a.dispatchEvent(c)},definePinchZoom=function(){var a=Math.min,b=Math.max,c=Math.abs,d=function(a,b){this.el=a,this.zoomFactor=1,this.lastScale=1,this.offset={x:0,y:0},this.initialOffset={x:0,y:0},this.options=Object.assign({},this.defaults,b),this.setupMarkup(),this.bindEvents(),this.update(),this.isImageLoaded(this.el)&&(this.updateAspectRatio(),this.setupOffsets()),this.enable()},e=function(c,a){return c+a},f=function(a,b){return a>b-.01&&a<b+.01};d.prototype={defaults:{tapZoomFactor:2,zoomOutFactor:1.3,animationDuration:300,maxZoom:4,minZoom:.5,draggableUnzoomed:!0,lockDragAxis:!1,setOffsetsOnce:!1,use2d:!0,zoomStartEventName:"pz_zoomstart",zoomUpdateEventName:"pz_zoomupdate",zoomEndEventName:"pz_zoomend",dragStartEventName:"pz_dragstart",dragUpdateEventName:"pz_dragupdate",dragEndEventName:"pz_dragend",doubleTapEventName:"pz_doubletap",verticalPadding:0,horizontalPadding:0,onZoomStart:null,onZoomEnd:null,onZoomUpdate:null,onDragStart:null,onDragEnd:null,onDragUpdate:null,onDoubleTap:null},handleDragStart:function(a){triggerEvent(this.el,this.options.dragStartEventName),"function"==typeof this.options.onDragStart&&this.options.onDragStart(this,a),this.stopAnimation(),this.lastDragPosition=!1,this.hasInteraction=!0,this.handleDrag(a)},handleDrag:function(a){var b=this.getTouches(a)[0];this.drag(b,this.lastDragPosition),this.offset=this.sanitizeOffset(this.offset),this.lastDragPosition=b},handleDragEnd:function(){triggerEvent(this.el,this.options.dragEndEventName),"function"==typeof this.options.onDragEnd&&this.options.onDragEnd(this,event),this.end()},handleZoomStart:function(a){triggerEvent(this.el,this.options.zoomStartEventName),"function"==typeof this.options.onZoomStart&&this.options.onZoomStart(this,a),this.stopAnimation(),this.lastScale=1,this.nthZoom=0,this.lastZoomCenter=!1,this.hasInteraction=!0},handleZoom:function(a,b){var c=this.getTouchCenter(this.getTouches(a)),d=b/this.lastScale;this.lastScale=b,this.nthZoom+=1,3<this.nthZoom&&(this.scale(d,c),this.drag(c,this.lastZoomCenter)),this.lastZoomCenter=c},handleZoomEnd:function(){triggerEvent(this.el,this.options.zoomEndEventName),"function"==typeof this.options.onZoomEnd&&this.options.onZoomEnd(this,event),this.end()},handleDoubleTap:function(a){var b=this.getTouches(a)[0],c=1<this.zoomFactor?1:this.options.tapZoomFactor,d=this.zoomFactor,e=function(a){this.scaleTo(d+a*(c-d),b)}.bind(this);this.hasInteraction||(this.isDoubleTap=!0,d>c&&(b=this.getCurrentZoomCenter()),this.animate(this.options.animationDuration,e,this.swing),triggerEvent(this.el,this.options.doubleTapEventName),"function"==typeof this.options.onDoubleTap&&this.options.onDoubleTap(this,a))},computeInitialOffset:function(){this.initialOffset={x:-c(this.el.offsetWidth*this.getInitialZoomFactor()-this.container.offsetWidth)/2,y:-c(this.el.offsetHeight*this.getInitialZoomFactor()-this.container.offsetHeight)/2}},resetOffset:function(){this.offset.x=this.initialOffset.x,this.offset.y=this.initialOffset.y},isImageLoaded:function(a){return"IMG"===a.nodeName?a.complete&&0!==a.naturalHeight:Array.from(a.querySelectorAll("img")).every(this.isImageLoaded)},setupOffsets:function(){this.options.setOffsetsOnce&&this._isOffsetsSet||(this._isOffsetsSet=!0,this.computeInitialOffset(),this.resetOffset())},sanitizeOffset:function(c){var d=this.el.offsetWidth*this.getInitialZoomFactor()*this.zoomFactor,e=this.el.offsetHeight*this.getInitialZoomFactor()*this.zoomFactor,f=d-this.getContainerX()+this.options.horizontalPadding,g=e-this.getContainerY()+this.options.verticalPadding,h=b(f,0),i=b(g,0),j=a(f,0)-this.options.horizontalPadding,k=a(g,0)-this.options.verticalPadding;return{x:a(b(c.x,j),h),y:a(b(c.y,k),i)}},scaleTo:function(a,b){this.scale(a/this.zoomFactor,b)},scale:function(a,b){a=this.scaleZoomFactor(a),this.addOffset({x:(a-1)*(b.x+this.offset.x),y:(a-1)*(b.y+this.offset.y)}),triggerEvent(this.el,this.options.zoomUpdateEventName),"function"==typeof this.options.onZoomUpdate&&this.options.onZoomUpdate(this,event)},scaleZoomFactor:function(c){var d=this.zoomFactor;return this.zoomFactor*=c,this.zoomFactor=a(this.options.maxZoom,b(this.zoomFactor,this.options.minZoom)),this.zoomFactor/d},canDrag:function(){return this.options.draggableUnzoomed||!f(this.zoomFactor,1)},drag:function(a,b){b&&(this.options.lockDragAxis?c(a.x-b.x)>c(a.y-b.y)?this.addOffset({x:-(a.x-b.x),y:0}):this.addOffset({y:-(a.y-b.y),x:0}):this.addOffset({y:-(a.y-b.y),x:-(a.x-b.x)}),triggerEvent(this.el,this.options.dragUpdateEventName),"function"==typeof this.options.onDragUpdate&&this.options.onDragUpdate(this,event))},getTouchCenter:function(a){return this.getVectorAvg(a)},getVectorAvg:function(a){return{x:a.map(function(a){return a.x}).reduce(e)/a.length,y:a.map(function(a){return a.y}).reduce(e)/a.length}},addOffset:function(a){this.offset={x:this.offset.x+a.x,y:this.offset.y+a.y}},sanitize:function(){this.zoomFactor<this.options.zoomOutFactor?this.zoomOutAnimation():this.isInsaneOffset(this.offset)&&this.sanitizeOffsetAnimation()},isInsaneOffset:function(a){var b=this.sanitizeOffset(a);return b.x!==a.x||b.y!==a.y},sanitizeOffsetAnimation:function(){var a=this.sanitizeOffset(this.offset),b={x:this.offset.x,y:this.offset.y},c=function(c){this.offset.x=b.x+c*(a.x-b.x),this.offset.y=b.y+c*(a.y-b.y),this.update()}.bind(this);this.animate(this.options.animationDuration,c,this.swing)},zoomOutAnimation:function(){if(1!==this.zoomFactor){var a=this.zoomFactor,b=this.getCurrentZoomCenter(),c=function(c){this.scaleTo(a+c*(1-a),b)}.bind(this);this.animate(this.options.animationDuration,c,this.swing)}},updateAspectRatio:function(){this.unsetContainerY(),this.setContainerY(this.container.parentElement.offsetHeight)},getInitialZoomFactor:function(){var b=this.container.offsetWidth/this.el.offsetWidth,c=this.container.offsetHeight/this.el.offsetHeight;return a(b,c)},getAspectRatio:function(){return this.el.offsetWidth/this.el.offsetHeight},getCurrentZoomCenter:function(){var a=this.offset.x-this.initialOffset.x,b=-1*this.offset.x-a/(1/this.zoomFactor-1),c=this.offset.y-this.initialOffset.y,d=-1*this.offset.y-c/(1/this.zoomFactor-1);return{x:b,y:d}},getTouches:function(a){var b=this.container.getBoundingClientRect(),c=document.documentElement.scrollTop||document.body.scrollTop,d=document.documentElement.scrollLeft||document.body.scrollLeft,e=b.top+c,f=b.left+d;return Array.prototype.slice.call(a.touches).map(function(a){return{x:a.pageX-f,y:a.pageY-e}})},animate:function(a,b,c,d){var e=new Date().getTime(),f=function(){if(this.inAnimation){var g=new Date().getTime()-e,h=g/a;g>=a?(b(1),d&&d(),this.update(),this.stopAnimation(),this.update()):(c&&(h=c(h)),b(h),this.update(),requestAnimationFrame(f))}}.bind(this);this.inAnimation=!0,requestAnimationFrame(f)},stopAnimation:function(){this.inAnimation=!1},swing:function(a){return-Math.cos(a*Math.PI)/2+.5},getContainerX:function(){return this.container.offsetWidth},getContainerY:function(){return this.container.offsetHeight},setContainerY:function(a){return this.container.style.height=a+"px"},unsetContainerY:function(){this.container.style.height=null},setupMarkup:function(){this.container=buildElement("<div class=\"pinch-zoom-container\"></div>"),this.el.parentNode.insertBefore(this.container,this.el),this.container.appendChild(this.el),this.container.style.overflow="hidden",this.container.style.position="relative",this.el.style.webkitTransformOrigin="0% 0%",this.el.style.mozTransformOrigin="0% 0%",this.el.style.msTransformOrigin="0% 0%",this.el.style.oTransformOrigin="0% 0%",this.el.style.transformOrigin="0% 0%",this.el.style.position="absolute"},end:function(){this.hasInteraction=!1,this.sanitize(),this.update()},bindEvents:function(){var a=this;g(this.container,this),window.addEventListener("resize",this.update.bind(this)),Array.from(this.el.querySelectorAll("img")).forEach(function(b){b.addEventListener("load",a.update.bind(a))}),"IMG"===this.el.nodeName&&this.el.addEventListener("load",this.update.bind(this))},update:function(a){this.updatePlaned||(this.updatePlaned=!0,window.setTimeout(function(){this.updatePlaned=!1,a&&"resize"===a.type&&(this.updateAspectRatio(),this.setupOffsets()),a&&"load"===a.type&&(this.updateAspectRatio(),this.setupOffsets());var b=this.getInitialZoomFactor()*this.zoomFactor,c=-this.offset.x/b,d=-this.offset.y/b,e="scale3d("+b+", "+b+",1) translate3d("+c+"px,"+d+"px,0px)",f="scale("+b+", "+b+") translate("+c+"px,"+d+"px)",g=function(){this.clone&&(this.clone.parentNode.removeChild(this.clone),delete this.clone)}.bind(this);!this.options.use2d||this.hasInteraction||this.inAnimation?(this.is3d=!0,g(),this.el.style.webkitTransform=e,this.el.style.mozTransform=f,this.el.style.msTransform=f,this.el.style.oTransform=f,this.el.style.transform=e):(this.is3d&&(this.clone=this.el.cloneNode(!0),this.clone.style.pointerEvents="none",this.container.appendChild(this.clone),window.setTimeout(g,200)),this.el.style.webkitTransform=f,this.el.style.mozTransform=f,this.el.style.msTransform=f,this.el.style.oTransform=f,this.el.style.transform=f,this.is3d=!1)}.bind(this),0))},enable:function(){this.enabled=!0},disable:function(){this.enabled=!1}};var g=function(a,b){var c=null,d=0,e=null,f=null,g=function(a,d){c!==a&&(c&&!a&&("zoom"===c?b.handleZoomEnd(d):"drag"===c?b.handleDragEnd(d):void 0),"zoom"===a?b.handleZoomStart(d):"drag"===a?b.handleDragStart(d):void 0);c=a},h=function(a){2===d?g("zoom"):1===d&&b.canDrag()?g("drag",a):g(null,a)},i=function(a){return Array.from(a).map(function(a){return{x:a.pageX,y:a.pageY}})},j=function(c,a){var d,e,b=Math.sqrt;return d=c.x-a.x,e=c.y-a.y,b(d*d+e*e)},k=function(a,b){var c=j(a[0],a[1]),d=j(b[0],b[1]);return d/c},l=function(a){a.stopPropagation(),a.preventDefault()},m=function(a){var f=new Date().getTime();1<d&&(e=null);300>f-e?(l(a),b.handleDoubleTap(a),"zoom"===c?b.handleZoomEnd(a):"drag"===c?b.handleDragEnd(a):void 0):b.isDoubleTap=!1;1===d&&(e=f)},n=!0;a.addEventListener("touchstart",function(a){b.enabled&&(n=!0,d=a.touches.length,m(a))}),a.addEventListener("touchmove",function(a){b.enabled&&!b.isDoubleTap&&(n?(h(a),c&&l(a),f=i(a.touches)):("zoom"===c?2==f.length&&2==a.touches.length&&b.handleZoom(a,k(f,i(a.touches))):"drag"===c?b.handleDrag(a):void 0,c&&(l(a),b.update())),n=!1)}),a.addEventListener("touchend",function(a){b.enabled&&(d=a.touches.length,h(a))})};return d},PinchZoom=definePinchZoom();export default PinchZoom;
\ No newline at end of file
diff --git a/dist/pinch-zoom.umd.js b/dist/pinch-zoom.umd.js
index 69c6332..02e1067 100644
--- a/dist/pinch-zoom.umd.js
+++ b/dist/pinch-zoom.umd.js
@@ -17,23 +17,23 @@
         value: true
     });
     /*
-
+    
         PinchZoom.js
         Copyright (c) Manuel Stofer 2013 - today
-
+    
         Author: Manuel Stofer (mst@rtp.ch)
-        Version: 2.3.2
-
+        Version: 2.3.3
+    
         Permission is hereby granted, free of charge, to any person obtaining a copy
         of this software and associated documentation files (the "Software"), to deal
         in the Software without restriction, including without limitation the rights
         to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
         copies of the Software, and to permit persons to whom the Software is
         furnished to do so, subject to the following conditions:
-
+    
         The above copyright notice and this permission notice shall be included in
         all copies or substantial portions of the Software.
-
+    
         THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
         IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
         FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -41,7 +41,7 @@
         LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
         OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
         THE SOFTWARE.
-
+    
     */
 
     // polyfills
@@ -158,7 +158,14 @@
                 dragEndEventName: 'pz_dragend',
                 doubleTapEventName: 'pz_doubletap',
                 verticalPadding: 0,
-                horizontalPadding: 0
+                horizontalPadding: 0,
+                onZoomStart: null,
+                onZoomEnd: null,
+                onZoomUpdate: null,
+                onDragStart: null,
+                onDragEnd: null,
+                onDragUpdate: null,
+                onDoubleTap: null
             },
 
             /**
@@ -167,6 +174,9 @@
              */
             handleDragStart: function handleDragStart(event) {
                 triggerEvent(this.el, this.options.dragStartEventName);
+                if (typeof this.options.onDragStart == "function") {
+                    this.options.onDragStart(this, event);
+                }
                 this.stopAnimation();
                 this.lastDragPosition = false;
                 this.hasInteraction = true;
@@ -186,6 +196,9 @@
 
             handleDragEnd: function handleDragEnd() {
                 triggerEvent(this.el, this.options.dragEndEventName);
+                if (typeof this.options.onDragEnd == "function") {
+                    this.options.onDragEnd(this, event);
+                }
                 this.end();
             },
 
@@ -195,6 +208,9 @@
              */
             handleZoomStart: function handleZoomStart(event) {
                 triggerEvent(this.el, this.options.zoomStartEventName);
+                if (typeof this.options.onZoomStart == "function") {
+                    this.options.onZoomStart(this, event);
+                }
                 this.stopAnimation();
                 this.lastScale = 1;
                 this.nthZoom = 0;
@@ -224,6 +240,9 @@
 
             handleZoomEnd: function handleZoomEnd() {
                 triggerEvent(this.el, this.options.zoomEndEventName);
+                if (typeof this.options.onZoomEnd == "function") {
+                    this.options.onZoomEnd(this, event);
+                }
                 this.end();
             },
 
@@ -251,6 +270,9 @@
 
                 this.animate(this.options.animationDuration, updateProgress, this.swing);
                 triggerEvent(this.el, this.options.doubleTapEventName);
+                if (typeof this.options.onDoubleTap == "function") {
+                    this.options.onDoubleTap(this, event);
+                }
             },
 
             /**
@@ -337,6 +359,9 @@
                     y: (_scale - 1) * (center.y + this.offset.y)
                 });
                 triggerEvent(this.el, this.options.zoomUpdateEventName);
+                if (typeof this.options.onZoomUpdate == "function") {
+                    this.options.onZoomUpdate(this, event);
+                }
             },
 
             /**
@@ -390,6 +415,9 @@
                         });
                     }
                     triggerEvent(this.el, this.options.dragUpdateEventName);
+                    if (typeof this.options.onDragUpdate == "function") {
+                        this.options.onDragUpdate(this, event);
+                    }
                 }
             },
 
@@ -857,7 +885,9 @@
                     } else {
                         switch (interaction) {
                             case 'zoom':
-                                target.handleZoom(event, calculateScale(startTouches, targetTouches(event.touches)));
+                                if (startTouches.length == 2 && event.touches.length == 2) {
+                                    target.handleZoom(event, calculateScale(startTouches, targetTouches(event.touches)));
+                                }
                                 break;
                             case 'drag':
                                 target.handleDrag(event);
diff --git a/dist/pinch-zoom.umd.min.js b/dist/pinch-zoom.umd.min.js
new file mode 100644
index 0000000..8441fa6
--- /dev/null
+++ b/dist/pinch-zoom.umd.min.js
@@ -0,0 +1 @@
+(function(a,b){if("function"==typeof define&&define.amd)define(["exports"],b);else if("undefined"!=typeof exports)b(exports);else{var c={exports:{}};b(c.exports),a.PinchZoom=c.exports}})(this,function(a){'use strict';Object.defineProperty(a,"__esModule",{value:!0}),"function"!=typeof Object.assign&&Object.defineProperty(Object,"assign",{value:function(a){if(null==a)throw new TypeError("Cannot convert undefined or null to object");for(var b,c=Object(a),d=1;d<arguments.length;d++)if(b=arguments[d],null!=b)for(var e in b)Object.prototype.hasOwnProperty.call(b,e)&&(c[e]=b[e]);return c},writable:!0,configurable:!0}),"function"!=typeof Array.from&&(Array.from=function(a){return[].slice.call(a)});var b=function(a){var b=document.implementation.createHTMLDocument("");return b.body.innerHTML=a,Array.from(b.body.children)[0]},c=function(a,b){var c=document.createEvent("HTMLEvents");c.initEvent(b,!0,!1),a.dispatchEvent(c)},d=function(){var a=Math.min,d=Math.max,e=Math.abs,f=function(a,b){this.el=a,this.zoomFactor=1,this.lastScale=1,this.offset={x:0,y:0},this.initialOffset={x:0,y:0},this.options=Object.assign({},this.defaults,b),this.setupMarkup(),this.bindEvents(),this.update(),this.isImageLoaded(this.el)&&(this.updateAspectRatio(),this.setupOffsets()),this.enable()},g=function(c,a){return c+a},h=function(a,b){return a>b-.01&&a<b+.01};f.prototype={defaults:{tapZoomFactor:2,zoomOutFactor:1.3,animationDuration:300,maxZoom:4,minZoom:.5,draggableUnzoomed:!0,lockDragAxis:!1,setOffsetsOnce:!1,use2d:!0,zoomStartEventName:"pz_zoomstart",zoomUpdateEventName:"pz_zoomupdate",zoomEndEventName:"pz_zoomend",dragStartEventName:"pz_dragstart",dragUpdateEventName:"pz_dragupdate",dragEndEventName:"pz_dragend",doubleTapEventName:"pz_doubletap",verticalPadding:0,horizontalPadding:0,onZoomStart:null,onZoomEnd:null,onZoomUpdate:null,onDragStart:null,onDragEnd:null,onDragUpdate:null,onDoubleTap:null},handleDragStart:function(a){c(this.el,this.options.dragStartEventName),"function"==typeof this.options.onDragStart&&this.options.onDragStart(this,a),this.stopAnimation(),this.lastDragPosition=!1,this.hasInteraction=!0,this.handleDrag(a)},handleDrag:function(a){var b=this.getTouches(a)[0];this.drag(b,this.lastDragPosition),this.offset=this.sanitizeOffset(this.offset),this.lastDragPosition=b},handleDragEnd:function(){c(this.el,this.options.dragEndEventName),"function"==typeof this.options.onDragEnd&&this.options.onDragEnd(this,event),this.end()},handleZoomStart:function(a){c(this.el,this.options.zoomStartEventName),"function"==typeof this.options.onZoomStart&&this.options.onZoomStart(this,a),this.stopAnimation(),this.lastScale=1,this.nthZoom=0,this.lastZoomCenter=!1,this.hasInteraction=!0},handleZoom:function(a,b){var c=this.getTouchCenter(this.getTouches(a)),d=b/this.lastScale;this.lastScale=b,this.nthZoom+=1,3<this.nthZoom&&(this.scale(d,c),this.drag(c,this.lastZoomCenter)),this.lastZoomCenter=c},handleZoomEnd:function(){c(this.el,this.options.zoomEndEventName),"function"==typeof this.options.onZoomEnd&&this.options.onZoomEnd(this,event),this.end()},handleDoubleTap:function(a){var b=this.getTouches(a)[0],d=1<this.zoomFactor?1:this.options.tapZoomFactor,e=this.zoomFactor,f=function(a){this.scaleTo(e+a*(d-e),b)}.bind(this);this.hasInteraction||(this.isDoubleTap=!0,e>d&&(b=this.getCurrentZoomCenter()),this.animate(this.options.animationDuration,f,this.swing),c(this.el,this.options.doubleTapEventName),"function"==typeof this.options.onDoubleTap&&this.options.onDoubleTap(this,a))},computeInitialOffset:function(){this.initialOffset={x:-e(this.el.offsetWidth*this.getInitialZoomFactor()-this.container.offsetWidth)/2,y:-e(this.el.offsetHeight*this.getInitialZoomFactor()-this.container.offsetHeight)/2}},resetOffset:function(){this.offset.x=this.initialOffset.x,this.offset.y=this.initialOffset.y},isImageLoaded:function(a){return"IMG"===a.nodeName?a.complete&&0!==a.naturalHeight:Array.from(a.querySelectorAll("img")).every(this.isImageLoaded)},setupOffsets:function(){this.options.setOffsetsOnce&&this._isOffsetsSet||(this._isOffsetsSet=!0,this.computeInitialOffset(),this.resetOffset())},sanitizeOffset:function(b){var c=this.el.offsetWidth*this.getInitialZoomFactor()*this.zoomFactor,e=this.el.offsetHeight*this.getInitialZoomFactor()*this.zoomFactor,f=c-this.getContainerX()+this.options.horizontalPadding,g=e-this.getContainerY()+this.options.verticalPadding,h=d(f,0),i=d(g,0),j=a(f,0)-this.options.horizontalPadding,k=a(g,0)-this.options.verticalPadding;return{x:a(d(b.x,j),h),y:a(d(b.y,k),i)}},scaleTo:function(a,b){this.scale(a/this.zoomFactor,b)},scale:function(a,b){a=this.scaleZoomFactor(a),this.addOffset({x:(a-1)*(b.x+this.offset.x),y:(a-1)*(b.y+this.offset.y)}),c(this.el,this.options.zoomUpdateEventName),"function"==typeof this.options.onZoomUpdate&&this.options.onZoomUpdate(this,event)},scaleZoomFactor:function(b){var c=this.zoomFactor;return this.zoomFactor*=b,this.zoomFactor=a(this.options.maxZoom,d(this.zoomFactor,this.options.minZoom)),this.zoomFactor/c},canDrag:function(){return this.options.draggableUnzoomed||!h(this.zoomFactor,1)},drag:function(a,b){b&&(this.options.lockDragAxis?e(a.x-b.x)>e(a.y-b.y)?this.addOffset({x:-(a.x-b.x),y:0}):this.addOffset({y:-(a.y-b.y),x:0}):this.addOffset({y:-(a.y-b.y),x:-(a.x-b.x)}),c(this.el,this.options.dragUpdateEventName),"function"==typeof this.options.onDragUpdate&&this.options.onDragUpdate(this,event))},getTouchCenter:function(a){return this.getVectorAvg(a)},getVectorAvg:function(a){return{x:a.map(function(a){return a.x}).reduce(g)/a.length,y:a.map(function(a){return a.y}).reduce(g)/a.length}},addOffset:function(a){this.offset={x:this.offset.x+a.x,y:this.offset.y+a.y}},sanitize:function(){this.zoomFactor<this.options.zoomOutFactor?this.zoomOutAnimation():this.isInsaneOffset(this.offset)&&this.sanitizeOffsetAnimation()},isInsaneOffset:function(a){var b=this.sanitizeOffset(a);return b.x!==a.x||b.y!==a.y},sanitizeOffsetAnimation:function(){var a=this.sanitizeOffset(this.offset),b={x:this.offset.x,y:this.offset.y},c=function(c){this.offset.x=b.x+c*(a.x-b.x),this.offset.y=b.y+c*(a.y-b.y),this.update()}.bind(this);this.animate(this.options.animationDuration,c,this.swing)},zoomOutAnimation:function(){if(1!==this.zoomFactor){var a=this.zoomFactor,b=this.getCurrentZoomCenter(),c=function(c){this.scaleTo(a+c*(1-a),b)}.bind(this);this.animate(this.options.animationDuration,c,this.swing)}},updateAspectRatio:function(){this.unsetContainerY(),this.setContainerY(this.container.parentElement.offsetHeight)},getInitialZoomFactor:function(){var b=this.container.offsetWidth/this.el.offsetWidth,c=this.container.offsetHeight/this.el.offsetHeight;return a(b,c)},getAspectRatio:function(){return this.el.offsetWidth/this.el.offsetHeight},getCurrentZoomCenter:function(){var a=this.offset.x-this.initialOffset.x,b=-1*this.offset.x-a/(1/this.zoomFactor-1),c=this.offset.y-this.initialOffset.y,d=-1*this.offset.y-c/(1/this.zoomFactor-1);return{x:b,y:d}},getTouches:function(a){var b=this.container.getBoundingClientRect(),c=document.documentElement.scrollTop||document.body.scrollTop,d=document.documentElement.scrollLeft||document.body.scrollLeft,e=b.top+c,f=b.left+d;return Array.prototype.slice.call(a.touches).map(function(a){return{x:a.pageX-f,y:a.pageY-e}})},animate:function(a,b,c,d){var e=new Date().getTime(),f=function(){if(this.inAnimation){var g=new Date().getTime()-e,h=g/a;g>=a?(b(1),d&&d(),this.update(),this.stopAnimation(),this.update()):(c&&(h=c(h)),b(h),this.update(),requestAnimationFrame(f))}}.bind(this);this.inAnimation=!0,requestAnimationFrame(f)},stopAnimation:function(){this.inAnimation=!1},swing:function(a){return-Math.cos(a*Math.PI)/2+.5},getContainerX:function(){return this.container.offsetWidth},getContainerY:function(){return this.container.offsetHeight},setContainerY:function(a){return this.container.style.height=a+"px"},unsetContainerY:function(){this.container.style.height=null},setupMarkup:function(){this.container=b("<div class=\"pinch-zoom-container\"></div>"),this.el.parentNode.insertBefore(this.container,this.el),this.container.appendChild(this.el),this.container.style.overflow="hidden",this.container.style.position="relative",this.el.style.webkitTransformOrigin="0% 0%",this.el.style.mozTransformOrigin="0% 0%",this.el.style.msTransformOrigin="0% 0%",this.el.style.oTransformOrigin="0% 0%",this.el.style.transformOrigin="0% 0%",this.el.style.position="absolute"},end:function(){this.hasInteraction=!1,this.sanitize(),this.update()},bindEvents:function(){var a=this;i(this.container,this),window.addEventListener("resize",this.update.bind(this)),Array.from(this.el.querySelectorAll("img")).forEach(function(b){b.addEventListener("load",a.update.bind(a))}),"IMG"===this.el.nodeName&&this.el.addEventListener("load",this.update.bind(this))},update:function(a){this.updatePlaned||(this.updatePlaned=!0,window.setTimeout(function(){this.updatePlaned=!1,a&&"resize"===a.type&&(this.updateAspectRatio(),this.setupOffsets()),a&&"load"===a.type&&(this.updateAspectRatio(),this.setupOffsets());var b=this.getInitialZoomFactor()*this.zoomFactor,c=-this.offset.x/b,d=-this.offset.y/b,e="scale3d("+b+", "+b+",1) translate3d("+c+"px,"+d+"px,0px)",f="scale("+b+", "+b+") translate("+c+"px,"+d+"px)",g=function(){this.clone&&(this.clone.parentNode.removeChild(this.clone),delete this.clone)}.bind(this);!this.options.use2d||this.hasInteraction||this.inAnimation?(this.is3d=!0,g(),this.el.style.webkitTransform=e,this.el.style.mozTransform=f,this.el.style.msTransform=f,this.el.style.oTransform=f,this.el.style.transform=e):(this.is3d&&(this.clone=this.el.cloneNode(!0),this.clone.style.pointerEvents="none",this.container.appendChild(this.clone),window.setTimeout(g,200)),this.el.style.webkitTransform=f,this.el.style.mozTransform=f,this.el.style.msTransform=f,this.el.style.oTransform=f,this.el.style.transform=f,this.is3d=!1)}.bind(this),0))},enable:function(){this.enabled=!0},disable:function(){this.enabled=!1}};var i=function(a,b){var c=null,d=0,e=null,f=null,g=function(a,d){c!==a&&(c&&!a&&("zoom"===c?b.handleZoomEnd(d):"drag"===c?b.handleDragEnd(d):void 0),"zoom"===a?b.handleZoomStart(d):"drag"===a?b.handleDragStart(d):void 0);c=a},h=function(a){2===d?g("zoom"):1===d&&b.canDrag()?g("drag",a):g(null,a)},i=function(a){return Array.from(a).map(function(a){return{x:a.pageX,y:a.pageY}})},j=function(c,a){var d,e,b=Math.sqrt;return d=c.x-a.x,e=c.y-a.y,b(d*d+e*e)},k=function(a,b){var c=j(a[0],a[1]),d=j(b[0],b[1]);return d/c},l=function(a){a.stopPropagation(),a.preventDefault()},m=function(a){var f=new Date().getTime();1<d&&(e=null);300>f-e?(l(a),b.handleDoubleTap(a),"zoom"===c?b.handleZoomEnd(a):"drag"===c?b.handleDragEnd(a):void 0):b.isDoubleTap=!1;1===d&&(e=f)},n=!0;a.addEventListener("touchstart",function(a){b.enabled&&(n=!0,d=a.touches.length,m(a))}),a.addEventListener("touchmove",function(a){b.enabled&&!b.isDoubleTap&&(n?(h(a),c&&l(a),f=i(a.touches)):("zoom"===c?2==f.length&&2==a.touches.length&&b.handleZoom(a,k(f,i(a.touches))):"drag"===c?b.handleDrag(a):void 0,c&&(l(a),b.update())),n=!1)}),a.addEventListener("touchend",function(a){b.enabled&&(d=a.touches.length,h(a))})};return f}();a.default=d});
\ No newline at end of file
diff --git a/package.json b/package.json
index 440101a..e7f21ab 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "pinch-zoom-js",
-  "version": "2.3.2",
+  "version": "2.3.3",
   "description": "Browser library for multi-touch gestures to zoom and drag on any DOM element.",
   "author": "Manuel Stofer",
   "license": "MIT",
@@ -26,6 +26,7 @@
   "typings": "src/pinch-zoom.d.ts",
   "devDependencies": {
     "babel-cli": "~6.26.0",
+    "babel-minify": "^0.5.0",
     "babel-preset-env": "~1.6.1"
   },
   "scripts": {
diff --git a/script/build.sh b/script/build.sh
index 5692479..3fec3ba 100755
--- a/script/build.sh
+++ b/script/build.sh
@@ -6,3 +6,7 @@ mkdir dist
 
 # UMD build
 babel src/pinch-zoom.js -o dist/pinch-zoom.umd.js
+
+# Minify
+babel-minify --sourceType module src/pinch-zoom.js -o dist/pinch-zoom.min.js
+babel-minify dist/pinch-zoom.umd.js -o dist/pinch-zoom.umd.min.js
diff --git a/src/pinch-zoom.js b/src/pinch-zoom.js
index 20de53d..7f211bb 100644
--- a/src/pinch-zoom.js
+++ b/src/pinch-zoom.js
@@ -4,7 +4,7 @@
     Copyright (c) Manuel Stofer 2013 - today
 
     Author: Manuel Stofer (mst@rtp.ch)
-    Version: 2.3.2
+    Version: 2.3.3
 
     Permission is hereby granted, free of charge, to any person obtaining a copy
     of this software and associated documentation files (the "Software"), to deal