import { pdfembGrabToPan } from "./grabtopan.js";

const core = {};

jQuery( document ).ready( function( $ ) {

	// Create, calculate and return the screen pixel ratio.
	var PIXEL_RATIO = (function() {
		var ctx = document.createElement( "canvas" ).getContext( "2d" ),
			dpr = window.devicePixelRatio || 1,
			bsr = ctx.webkitBackingStorePixelRatio ||
				ctx.mozBackingStorePixelRatio ||
				ctx.msBackingStorePixelRatio ||
				ctx.oBackingStorePixelRatio ||
				ctx.backingStorePixelRatio || 1;

		return dpr / bsr;
	})();

	core.PIXEL_RATIO = PIXEL_RATIO;

	var CANVAS_MAX_PIXELS = 16777000; // 16777216 is max on iPhone Safari

	var vscrollbarwidth = 0;
	var hscrollbarheight = 0;

	// Create the measurement node, measure, and delete it.
	(function() {
		// Create the measurement node
		var scrollDiv = document.createElement( "div" );
		scrollDiv.style.width = '100px';
		scrollDiv.style.height = '100px';
		scrollDiv.style.overflow = 'scroll';
		scrollDiv.style.position = 'absolute';
		scrollDiv.style.top = '-9999px';
		document.body.appendChild( scrollDiv );

		// Get the scrollbar width
		vscrollbarwidth = scrollDiv.offsetWidth - scrollDiv.clientWidth;
		hscrollbarheight = scrollDiv.offsetHeight - scrollDiv.clientHeight;

		// Delete the DIV
		document.body.removeChild( scrollDiv );
	})();

	core.vscrollbarwidth = vscrollbarwidth;
	core.hscrollbarheight = hscrollbarheight;

	var pdfembPagesViewer = function( pdfDoc, divContainer, showIsSecure ) {
		this.pdfDoc = pdfDoc;
		this.divContainer = divContainer;
		this.showIsSecure = showIsSecure;

		this.initialResize = false;
		this.firstPageWidth = 0;
		this.firstPageHeight = 0;
		this.invalidationRound = 1;
		this.currentPageNum = 0;
		this.zoom = 100;
		this.fromZoom = 0;
		this.toZoom = 0;
	};

	pdfembPagesViewer.prototype.setup = function() {
		var self = this;

		var divContainer = this.divContainer;
		var pdfDoc_ = this.pdfDoc;
		var showIsSecure = this.showIsSecure;

		this.numPages = pdfDoc_.numPages;

		var scrollbar = divContainer.data( 'scrollbar' );
		this.vscrollbar = scrollbar === 'both' || scrollbar === 'vertical';
		this.hscrollbar = scrollbar === 'both' || scrollbar === 'horizontal';

		var style = 'overflow-y: ' + (this.vscrollbar ? 'scroll' : 'hidden') + '; ';
		style += 'overflow-x: ' + (this.hscrollbar ? 'scroll' : 'hidden') + '; ';

		divContainer.empty().append(
			$( '<div></div>', { 'class': 'pdfemb-pagescontainer', 'style': style } ) );

		divContainer.data( 'pdfDoc', pdfDoc_ );

		var toolbar_location = divContainer.data( 'toolbar' );

		if ( toolbar_location === 'top' || toolbar_location === 'both' ) {
			this.addToolbar( true, divContainer.data( 'toolbar-fixed' ) === 'on', showIsSecure );
		}

		if ( toolbar_location === 'bottom' || toolbar_location === 'both' ) {
			this.addToolbar( false, divContainer.data( 'toolbar-fixed' ) === 'on', showIsSecure );
		}


		// Annotations layer
		// Set up annotations layer factory

		if ( typeof (core.pdfembPremiumAnnotationsLayerFactory) != 'undefined' ) {
			self.annotationsLayerFactory = new core.pdfembPremiumAnnotationsLayerFactory();
		}
		else {
			self.annotationsLayerFactory = {
				createAnnotationsLayerBuilder: function( pageDiv, pdfPage ) {
					return null;
				}
			}
		}
		self.annotationLayerFactories = Array();

		// Text Layer

		if ( typeof (core.pdfembPremiumTextLayerFactory) != 'undefined' ) {
			self.textLayerFactory = new core.pdfembPremiumTextLayerFactory();
		}
		else {
			self.textLayerFactory = {
				createTextLayerBuilder: function( pageDiv, pdfPage ) {
					return null;
				}
			}
		}
		self.textLayerFactories = Array();

		// React to page jump event

		divContainer.on( 'pdfembGotopage', function( e, pageNum ) {
			if ( pageNum > this.numPages || pageNum <= 0 ) {
				return;
			}

			self.gotoPage( pageNum );
			self.jumpToTop();

		} );

		divContainer.on( 'pdfembGotoHash', function( e, destobj ) {
			if ( ! destobj.dest ) {
				return;
			}
			dest = destobj.dest;

			var destinationPromise;
			if ( typeof dest === 'string' ) {
				destString = dest;
				destinationPromise = self.pdfDoc.getDestination( dest );
			}
			else {
				destinationPromise = Promise.resolve( dest );
			}
			destinationPromise.then( function( destination ) {

				if ( ! (destination instanceof Array) || destination.length < 1 ) {
					return; // invalid destination
				}

				self.pdfDoc.getPageIndex( destination[ 0 ] ).then( function( pageIndex ) {
					var pageNum = pageIndex + 1;

					if ( pageNum > self.numPages || pageNum <= 0 || self.currentPageNum == pageNum ) {
						return;
					}

					self.gotoPage( pageNum )
					self.jumpToTop();
				} );

			} );
		} );

		divContainer.on( 'pdfembGotoAction', function( e, action ) {
			var curPage = self.currentPageNum;
			var newPage = curPage;
			switch ( action ) {
				case 'GoBack':
					-- newPage;
					break;

				case 'GoForward':
					++ newPage;
					break;

				case 'NextPage':
					++ newPage;
					break;

				case 'PrevPage':
					-- newPage;
					break;

				case 'LastPage':
					newPage = self.pageCount;
					break;

				case 'FirstPage':
					newPage = 1;
					break;

				default:
					break; // No action according to spec
			}

			if ( newPage == curPage || newPage > self.pageCount || newPage <= 0 ) {
				return;
			}

			self.gotoPage( newPage );

		} );

		divContainer.on( 'pdfembMagnify', function( event ) {
			self.magnifyEvent( event );
		} );

		divContainer.on( 'pdfembChangeZoom', function( event, amt ) {
			self.changeZoom( amt );
		} );


		// Initial/first page rendering

		this.pageCount = pdfDoc_.numPages;

		if ( ! divContainer.data( 'pagenum' ) || divContainer.data( 'pagenum' ) < 1 || divContainer.data( 'pagenum' ) > this.pageCount ) {
			divContainer.data( 'pagenum', 1 );
		}

		divContainer.data( 'showIsSecure', this.showIsSecure );
		divContainer.data( 'pageNumPending', null );

		var startZoom = divContainer.data( 'fullScreen' ) == 'on' ? parseInt( divContainer.data( 'startfpzoom' ) ) : parseInt( divContainer.data( 'startzoom' ) );
		if ( isNaN( startZoom ) || startZoom < 20 || startZoom > 800 ) {
			startZoom = 100;
		}
		this.zoom = startZoom;
		if ( startZoom != 100 ) {
			divContainer.find( 'span.pdfemb-zoom' ).text( startZoom + '%' );
		}

		divContainer.find( 'span.pdfemb-page-count' ).text( this.pageCount );

		this.gotoPage( divContainer.data( 'pagenum' ) );

	};

	pdfembPagesViewer.prototype.checkForResize = function() {
		var self = this;
		var divContainer = self.divContainer;
		var newheight = $( window ).height();
		var newwidth = $( window ).width();

		var oldheight = divContainer.data( 'checked-window-height' );
		var oldwidth = divContainer.data( 'checked-window-width' );

		if ( ! oldheight || ! oldwidth ) {
			divContainer.data( 'checked-window-height', newheight );
			divContainer.data( 'checked-window-width', newwidth );
		}

		if ( oldheight !== newheight || oldwidth !== newwidth ) {
			self.resizeViewer();
			self.resizeInnerDivs();
			self.invalidateAllPages();
			self.renderPage( this.currentPageNum );
			self.prerenderNearbyPages( this.currentPageNum );
			self.pdfembMakeMobile();

			divContainer.data( 'checked-window-height', newheight );
			divContainer.data( 'checked-window-width', newwidth );
		}

		if ( divContainer.data( 'fullScreenClosed' ) !== 'true' ) {
			setTimeout( function() {
				self.checkForResize();
			}, 100 );
		}
	};

	pdfembPagesViewer.prototype.setSizesBasedOnPage = function( page ) {
		var vp = page.getViewport( 1.0 ); // scale = 1.0

		this.pageWidth = vp.width;
		this.pageHeight = vp.height;

		if ( this.pageWidth <= 0 || this.pageHeight <= 0 ) {
			this.divContainer.empty().append( document.createTextNode( pdfemb_trans.objectL10n.widthheightinvalid ) );
			return;
		}
	};

	pdfembPagesViewer.prototype.createPageInnerDivs = function() {
		var self = this;
		var pagesContainer = this.divContainer.find( '.pdfemb-pagescontainer' );

		for ( var i = 1; i <= this.pageCount; ++ i ) {
			var innerdiv = pagesContainer.find( '.pdfemb-inner-div.pdfemb-page' + i );
			if ( innerdiv.length == 0 ) {
				innerdiv = $( '<div></div>', { 'class': 'pdfemb-inner-div pdfemb-page' + i } );
				innerdiv.data( 'pageNum', i );
				pagesContainer.append( innerdiv );
			}
		}

		self.resizeInnerDivs();
	};

	pdfembPagesViewer.prototype.addGrabToPan = function() {
		window.pdfembGrabToPan = pdfembGrabToPan();

		var self = this;
		var divContainer = self.divContainer;
		var jpagesContainer = divContainer.find( 'div.pdfemb-pagescontainer' );

		var grabtopan = new window.pdfembGrabToPan( {
			element: jpagesContainer[ 0 ]
		} );

		divContainer.data( 'grabtopan', grabtopan );

		jpagesContainer.on( 'scroll', function( e ) {
			var pn = self.getTopVisiblePageNum();
			if ( self.currentPageNum !== pn ) {
				self.currentPageNum = pn;
				self.updatePageNumDisplay( pn );
				self.renderPage( pn, false );
				self.prerenderNearbyPages( pn );
				self.deallocateFarAwayPages( pn );
			}
			e.stopPropagation();
		} );

		$( window ).on( 'resize', function() {
			setTimeout( function() {
				self.checkForResize();
			}, 100 );
		} );
	};

	pdfembPagesViewer.prototype.resizeInnerDivs = function( pageNum ) {
		var self = this;
		var wantCanvasWidth = self.wantCanvasWidth,
			wantCanvasHeight = self.wantCanvasHeight,
			wantHeight = self.wantHeight;

		var pagesContainer = this.divContainer.find( '.pdfemb-pagescontainer' );

		var innerdivs = pagesContainer.find( '.pdfemb-inner-div' );

		if ( pageNum ) {
			innerdivs = innerdivs.filter( '.pdfemb-page' + pageNum );
		}

		var totalheight = 0;

		innerdivs.each( function( i, elt ) {

			var e = $( elt );

			var widthfactor = e.data( 'widthfactor' ),
				heightfactor = e.data( 'heightfactor' );

			if ( ! widthfactor ) {
				widthfactor = 1;
			}
			if ( ! heightfactor ) {
				heightfactor = 1;
			}

			e.data( 'invalidation-round', this.invalidationRound - 1 );

			e.css( 'width', wantCanvasWidth * widthfactor );

			var height = wantCanvasHeight * heightfactor
				+ (pageNum == self.numPages || (! pageNum && i == innerdivs.length - 1) ? 0 : 2);
			e.css( 'height', height );

			totalheight += height;

			var canvas = e.find( '.pdfemb-the-canvas' );

			canvas.css( 'width', wantCanvasWidth * widthfactor );
			canvas.css( 'height', wantCanvasHeight * heightfactor );
		} );

		var VMargin = 0;
		if ( ! pageNum && totalheight < wantHeight ) {
			VMargin = (wantHeight - totalheight) / 2;
		}
		innerdivs.first().css( 'top', VMargin );
	};

	pdfembPagesViewer.prototype.invalidateAllPages = function() {
		++ this.invalidationRound;
	};

	pdfembPagesViewer.prototype.prerenderNearbyPages = function( pageNum ) {
		var pagedelta_forward = 3, pagedelta_backward = 2;

		if ( this.zoom < 100 ) {
			pagedelta_forward *= Math.min( Math.ceil( 100 / this.zoom ), 10 );
			pagedelta_backward *= Math.min( Math.ceil( 100 / this.zoom ), 10 );
		}

		for ( var pn = Math.max( 1, pageNum - pagedelta_backward ); pn <= Math.min( pageNum + pagedelta_forward, this.numPages ); ++ pn ) {
			if ( pn != pageNum ) {
				this.renderPage( pn, false );
			}
		}
	};

	pdfembPagesViewer.prototype.deallocateFarAwayPages = function( pageNum ) {
		var pagedelta_forward = 2, pagedelta_backward = 2;

		if ( this.zoom < 100 ) {
			var extra_pages = Math.min( Math.ceil( 100 / this.zoom ), 50 );
			pagedelta_forward += extra_pages;
			pagedelta_backward += extra_pages;
		}

		var removeCanvas = function( pn ) {
			var pageInnerDiv = pagesContainer.find( '.pdfemb-page' + pn );
			var canvas = pageInnerDiv.find( '.pdfemb-the-canvas' );
			if ( canvas.length ) {
				canvas.width = 1;
				canvas.height = 1;
				// const ctx = canvas.getContext('2d');
				// ctx && ctx.clearRect(0, 0, 1, 1);
				canvas.remove();
				pageInnerDiv.data( 'invalidation-round', 0 );
			}
		};

		var pagesContainer = this.divContainer.find( 'div.pdfemb-pagescontainer' );
		var pn;

		for ( pn = 3; pn < pageNum - pagedelta_backward; ++ pn ) {
			removeCanvas( pn );
		}

		for ( pn = pageNum + pagedelta_forward; pn < this.numPages; ++ pn ) {
			removeCanvas( pn );
		}
	};

	pdfembPagesViewer.prototype.resizeViewer = function() {
		var self = this;
		var pageWidth = self.pageWidth,
			pageHeight = self.pageHeight,
			divContainer = self.divContainer;

		var pagesContainer = divContainer.find( 'div.pdfemb-pagescontainer' );

		var oldScrollLeft = pagesContainer[ 0 ].scrollLeft;
		var oldScrollTop = pagesContainer[ 0 ].scrollTop;

		// Max out at parent container width
		var parentWidth = divContainer.parent().width();

		var wantWidth = pageWidth;

		if ( divContainer.data( 'width' ) == 'max' ) {
			wantWidth = parentWidth;
		}
		else if ( divContainer.data( 'width' ) == 'auto' ) {
			wantWidth = pageWidth;
		}
		else {
			wantWidth = parseInt( divContainer.data( 'width' ), 10 );
			if ( isNaN( wantWidth ) || wantWidth <= 0 ) {
				wantWidth = parentWidth;
			}
		}

		if ( wantWidth <= 0 ) {
			wantWidth = pageWidth;
		}

		// Always max at the parent container width
		if ( wantWidth > parentWidth && parentWidth > 0 ) {
			wantWidth = parentWidth;
		}

		var wantHeight = pageHeight * wantWidth / pageWidth;

		var wantMobile = self.pdfembWantMobile( wantWidth, userHeight );

		self.wantMobile = wantMobile;

		var fixedToolbars = divContainer.find( 'div.pdfemb-toolbar-fixed' );

		var actualFixedToolbars = wantMobile ? 0 : fixedToolbars.length;

		// Height can be overridden by user
		var userHeight = parseInt( divContainer.data( 'height' ), 10 );
		if ( isNaN( userHeight ) || userHeight <= 0 || userHeight > wantHeight ) {
			if ( divContainer.data( 'height' ) == "auto" ) { // Mainly for full screen mode
				userHeight = divContainer.parent().height() - actualFixedToolbars * fixedToolbars.height();
			}
			else { // max
				userHeight = wantHeight;
			}
		}

		self.userHeight = userHeight;

		wantWidth = Math.floor( wantWidth );
		wantHeight = Math.floor( wantHeight );


		var zoom = 100;

		var wantCanvasWidth = wantWidth - (self.vscrollbar ? vscrollbarwidth : 0);
		var wantCanvasHeight = wantHeight - (self.hscrollbar ? hscrollbarheight : 0);

		var reducefactor = 1;

		if ( ! wantMobile ) {

			zoom = self.zoom;

			wantCanvasWidth = wantCanvasWidth * zoom / 100;
			wantCanvasHeight = wantCanvasHeight * zoom / 100;


			// Check canvas won't be too big
			if ( wantCanvasWidth * wantCanvasHeight * PIXEL_RATIO * PIXEL_RATIO > CANVAS_MAX_PIXELS ) {
				reducefactor = CANVAS_MAX_PIXELS / (wantCanvasWidth * wantCanvasHeight * PIXEL_RATIO * PIXEL_RATIO);
			}

		}

		// Set values

		if ( wantWidth != divContainer.width() ) {
			divContainer.width( wantWidth );
		}

		if ( divContainer.height() != userHeight ) {
			divContainer.height( userHeight + actualFixedToolbars * fixedToolbars.height() );
		}

		pagesContainer.width( wantWidth );
		pagesContainer.height( userHeight );

		var fixedTopToolbars = fixedToolbars.filter( '.pdfemb-toolbar-top' );
		if ( actualFixedToolbars > 0 ) {
			pagesContainer.css( 'top', fixedTopToolbars.height() );
		}

		var canvasscale = (wantWidth - (self.vscrollbar ? vscrollbarwidth : 0)) / pageWidth;

		if ( self.fromZoom != 0 && self.toZoom != 0 ) {

			var oldMidX = oldScrollLeft + self.pccentreLeft;
			var oldMidY = oldScrollTop + self.pccentreTop;

			pagesContainer[ 0 ].scrollLeft = (oldScrollLeft + self.pccentreLeft) * (self.toZoom / self.fromZoom) - self.pccentreLeft;
			pagesContainer[ 0 ].scrollTop = (oldScrollTop + self.pccentreTop) * (self.toZoom / self.fromZoom) - self.pccentreTop;
		}

		self.fromZoom = 0;
		self.toZoom = 0;

		self.wantCanvasWidth = wantCanvasWidth;
		self.wantCanvasHeight = wantCanvasHeight;
		self.reducefactor = reducefactor;

		self.wantWidth = wantWidth;
		self.wantHeight = wantHeight;
		self.canvasscale = canvasscale;
		self.zoom = zoom;
	};

	pdfembPagesViewer.prototype.getTopVisiblePageNum = function() {
		var pagesContainer = this.divContainer.find( '.pdfemb-pagescontainer' );
		var innerdivs = pagesContainer.find( '.pdfemb-inner-div:visible' );

		if ( innerdivs.length > 0 ) {
			return innerdivs.first().data( 'pageNum' );
		}
		return 1;
	};

	pdfembPagesViewer.prototype.gotoPage = function( pageNum ) {
		if ( pageNum <= 0 || pageNum > this.pageCount ) {
			return;
		}
		this.renderPage( pageNum, true );
		this.currentPageNum = pageNum;
		this.updatePageNumDisplay( pageNum );
		this.prerenderNearbyPages( pageNum );
		this.deallocateFarAwayPages( pageNum );

	};

	pdfembPagesViewer.prototype.updatePageNumDisplay = function( pageNum ) {
		var divContainer = this.divContainer;
		// Update page counters
		divContainer.find( 'div.pdfemb-toolbar .pdfemb-page-num' ).each( function( i, pageNumDisplay ) {
			var jpageNumDisplay = $( pageNumDisplay );
			if ( jpageNumDisplay.is( 'span' ) ) {
				// Normal span area
				jpageNumDisplay.text( pageNum );
			}
			else {
				// User-changeable text
				jpageNumDisplay.val( pageNum );
			}
		} );

		// Enable or disable next/prev buttons.
		if ( pageNum < this.pageCount ) {
			divContainer.find( '.pdfemb-next' ).prop( 'disabled', false ).removeClass( 'pdfemb-btndisabled' );
		}
		else {
			divContainer.find( '.pdfemb-next' ).prop( 'disabled', true ).addClass( 'pdfemb-btndisabled' );
		}

		if ( pageNum > 1 ) {
			divContainer.find( '.pdfemb-prev' ).prop( 'disabled', false ).removeClass( 'pdfemb-btndisabled' );
		}
		else {
			divContainer.find( '.pdfemb-prev' ).prop( 'disabled', true ).addClass( 'pdfemb-btndisabled' );
		}

	};

	pdfembPagesViewer.prototype.scrollPageIntoView = function( pageNum ) {
		var pagesContainer = this.divContainer.find( '.pdfemb-pagescontainer' );

		var innerdiv = pagesContainer.find( '.pdfemb-page' + pageNum );

		pagesContainer.find( '.pdfemb-inner-div' ).not( '.pdfemb-page' + pageNum ).hide();

		innerdiv.show();
		pagesContainer[ 0 ].scrollTop = 0;
	};

	pdfembPagesViewer.prototype.renderPage = function( pageNum, scrollIntoView ) {
		var self = this;

		var myInvalidationRound = self.invalidationRound;

		var divContainer = this.divContainer;

		// Using promise to fetch the page
		var pdfDoc = divContainer.data( 'pdfDoc' );

		var pagesContainer = divContainer.find( '.pdfemb-pagescontainer' );
		var innerdiv = pagesContainer.find( '.pdfemb-page' + pageNum );

		if ( innerdiv.length && innerdiv.data( 'invalidation-round' ) >= myInvalidationRound ) {
			if ( scrollIntoView ) {
				self.scrollPageIntoView( pageNum );
			}
			return;
		}

		var pendingInvalidationRound = innerdiv.data( 'pending-drawing-round' );

		if ( pendingInvalidationRound >= myInvalidationRound ) {
			// Already being drawn
			return;
		}
		else if ( pendingInvalidationRound > 0 && pendingInvalidationRound < myInvalidationRound ) {
			innerdiv.data( 'pending-drawing-round', myInvalidationRound );
			// Queue up this rendering - but we can't do it right now.
			return;
		}

		innerdiv.data( 'pending-drawing-round', myInvalidationRound );

		pdfDoc.getPage( pageNum ).then( function( page ) {

			if ( ! self.initialResize ) {
				self.initialResize = true;

				self.setSizesBasedOnPage( page );

				self.resizeViewer();

				self.createPageInnerDivs();

				self.addGrabToPan();

				self.pdfembMakeMobile();
			}

			// Lookup again if only just created
			if ( innerdiv.length === 0 ) {
				innerdiv = pagesContainer.find( '.pdfemb-page' + pageNum );
			}

			// Is this page the same size/shape as the first?

			var widthfactor = innerdiv.data( 'widthfactor' ),
				heightfactor = innerdiv.data( 'heightfactor' );

			if ( ! widthfactor || ! heightfactor ) {
				// calculate factors
				var vp = page.getViewport( 1.0 ); // scale = 1.0

				widthfactor = vp.width / self.pageWidth;
				heightfactor = vp.height / self.pageHeight;

				innerdiv.data( 'widthfactor', widthfactor );
				innerdiv.data( 'heightfactor', heightfactor );

				if ( widthfactor !== 1 || heightfactor !== 1 ) {
					self.resizeInnerDivs( pageNum );
				}
			}

			var canvas = innerdiv.find( '.pdfemb-the-canvas' );
			if ( canvas.length === 0 ) {
				canvas = $( '<canvas></canvas>', { 'class': 'pdfemb-the-canvas' } );
				innerdiv.append( canvas );
			}

			if ( scrollIntoView ) {
				self.scrollPageIntoView( pageNum );
			}

			var canvasImg = null;
			var canvasCxt = null;
			var oldCanvasWidth = null;
			var oldCanvasHeight = null;

			var wantCanvasWidth = self.wantCanvasWidth,
				wantCanvasHeight = self.wantCanvasHeight,
				canvasscale = self.canvasscale,
				zoom = self.zoom;

			canvas.css( 'width', wantCanvasWidth * widthfactor );
			canvas.css( 'height', wantCanvasHeight * heightfactor );

			if ( self.wantMobile ) {
				divContainer.data( 'grabtopan' ).deactivate();
			}
			else {
				divContainer.data( 'grabtopan' ).activate();
			}

			// Render PDF page into canvas context
			var viewport = page.getViewport( canvasscale * zoom / 100 );

			// if ( typeof offscreenCanvas !== 'undefined' ) {
			//     releaseCanvas( offscreenCanvas );
			// }
			var offscreenCanvas = document.createElement( 'canvas' );
			offscreenCanvas.width = wantCanvasWidth * PIXEL_RATIO * self.reducefactor * widthfactor;
			offscreenCanvas.height = wantCanvasHeight * PIXEL_RATIO * self.reducefactor * heightfactor;

			var ctx = offscreenCanvas.getContext( '2d' ); /* memory exceeded Total canvas memory use exceeds the maximum limit (224 MB).
			 drawCallback — pdfemb-pv-core-4.6.2.js:776 */
			var renderContext = {
				canvasContext: ctx,
				viewport: viewport,
				transform: [ PIXEL_RATIO * self.reducefactor,
					0,
					0,
					PIXEL_RATIO * self.reducefactor,
					0,
					0 ]
			};

			// No longer set transform on ctx explicitly
			// ctx.setTransform(PIXEL_RATIO, 0, 0, PIXEL_RATIO, 0, 0);
			// This was not always being picked up first time on some browsers - set via renderContext instead above

			var renderTask = page.render( renderContext );

			var drawCallback = function() {

				canvas[ 0 ].width = wantCanvasWidth * PIXEL_RATIO * self.reducefactor * widthfactor;
				canvas[ 0 ].height = wantCanvasHeight * PIXEL_RATIO * self.reducefactor * heightfactor;

				// Render any watermark to off-screen image
				self.preRenderCanvas( ctx, pageNum, zoom );

				// Copy from off screen canvas
				var image = ctx.getImageData( 0, 0, offscreenCanvas.width, offscreenCanvas.height );
				canvas[ 0 ].getContext( '2d' ).putImageData( image, 0, 0 );  /* memory exceeded Total canvas memory use exceeds the maximum limit (224 MB).
				 drawCallback — pdfemb-pv-core-4.6.2.js:776 */


				// Do annotations layer
				var annotationLayer = null;
				if ( typeof self.annotationLayerFactories[ pageNum ] == 'undefined' ) {
					annotationLayer = self.annotationsLayerFactory.createAnnotationsLayerBuilder( innerdiv[ 0 ], page );
					self.annotationLayerFactories[ pageNum ] = annotationLayer;
				}
				else {
					annotationLayer = self.annotationLayerFactories[ pageNum ];
				}

				if ( annotationLayer != null ) {
					annotationLayer.setupAnnotations( viewport, self.divContainer.data( 'newwindow' ) );
				}

				// End annotations layer


				// Do Text Layer

				var textLayer = null;
				if ( typeof self.textLayerFactories[ pageNum ] == 'undefined' ) {
					textLayer = self.textLayerFactory.createTextLayerBuilder( innerdiv[ 0 ], page );
					self.textLayerFactories[ pageNum ] = textLayer;
				}
				else {
					textLayer = self.textLayerFactories[ pageNum ];
				}

				if ( textLayer != null ) {
					textLayer.setupText( viewport );
				}
				// End Text Layer


				innerdiv.data( 'invalidation-round', myInvalidationRound );

				pendingInvalidationRound = innerdiv.data( 'pending-drawing-round' );

				innerdiv.data( 'pending-drawing-round', '' );

				if ( pendingInvalidationRound > myInvalidationRound ) {
					self.renderPage( pageNum, false );
				}


			}


			// Wait for rendering to finish
			renderTask.promise.then( function() {
				if ( 'requestAnimationFrame' in window ) {
					window.requestAnimationFrame( drawCallback );
					// releaseCanvas(canvas);
				}
				else {
					setTimeout( drawCallback, 1 );
					// releaseCanvas(canvas);
				}
			} );

			function releaseCanvas( canvas ) {
				canvas.width = 1;
				canvas.height = 1;
				const ctx = canvas.getContext( '2d' );
				ctx && ctx.clearRect( 0, 0, 1, 1 );
			}


		} );

	};

	pdfembPagesViewer.prototype.changeZoom = function( zoomdelta ) {
		var self = this;
		var divContainer = self.divContainer;

		var oldzoom = self.zoom;
		var newzoom = oldzoom + zoomdelta;
		self.zoom = newzoom;
		divContainer.find( 'span.pdfemb-zoom' ).text( newzoom + '%' );

		self.fromZoom = oldzoom;
		self.toZoom = newzoom;

		var pagesContainer = divContainer.find( '.pdfemb-pagescontainer' );
		self.pccentreLeft = pagesContainer.width() / 2;
		self.pccentreTop = pagesContainer.height() / 2;

		self.resizeViewer();
		self.resizeInnerDivs();
		self.invalidateAllPages();
		self.renderPage( self.currentPageNum );

		// Ensure top-left remains where it was

		/*var pagesContainer = divContainer.find('.pdfemb-pagescontainer');

		 var cscrolltop = pagesContainer[0].scrollTop;
		 pagesContainer[0].scrollTop = cscrolltop * newzoom / oldzoom;

		 var cscrollleft = pagesContainer[0].scrollLeft;
		 pagesContainer[0].scrollLeft = cscrollleft * newzoom / oldzoom; */


		self.prerenderNearbyPages( self.currentPageNum );
	};

	pdfembPagesViewer.prototype.queueRenderPage = function( num, noredraw ) {
		var divContainer = this.divContainer;
		this.renderPage( num, noredraw );

		/*if (divContainer.data('pageRendering')) {
		 divContainer.data('pageNumPending', num);
		 } else {
		 this.renderPage(num, noredraw);
		 }*/
	};

	pdfembPagesViewer.prototype.addToolbar = function( atTop, fixed, showIsSecure ) {
		var divContainer = this.divContainer;
		var self = this;

		var toolbar = $( '<div></div>', { 'class': 'pdfemb-toolbar pdfemb-toolbar' + (fixed ? '-fixed' : '-hover') + ' ' + (atTop ? 'pdfemb-toolbar-top' : 'pdfemb-toolbar-bottom') } );
		var prevbtn = $( '<button class="pdfemb-prev" title="' + pdfemb_trans.objectL10n.prev + '" type="button"></button>' );
		toolbar.append( prevbtn );
		var nextbtn = $( '<button class="pdfemb-next" title="' + pdfemb_trans.objectL10n.next + '" type="button"></button>' );
		toolbar.append( nextbtn );

		toolbar.append( $( '<div class="pdfemb-page-area">' + pdfemb_trans.objectL10n.page + ' <span class="pdfemb-page-num">0</span> / <span class="pdfemb-page-count"></span></div>' ) );

		var zoomoutbtn = $( '<button class="pdfemb-zoomout" title="' + pdfemb_trans.objectL10n.zoomout + '" type="button"></button>' );
		toolbar.append( zoomoutbtn );

		var zoominbtn = $( '<button class="pdfemb-zoomin" title="' + pdfemb_trans.objectL10n.zoomin + '" type="button"></button>' );
		toolbar.append( zoominbtn );

		toolbar.append( $( '<div>' + pdfemb_trans.objectL10n.zoom + ' <span class="pdfemb-zoom">100%</span></div>' ) );

		if ( showIsSecure ) {
			toolbar.append( $( '<div>' + pdfemb_trans.objectL10n.secure + '</div>' ) );
		}

		if ( atTop ) {
			divContainer.prepend( toolbar );
		}
		else {
			divContainer.append( toolbar );
		}

		// Add button functions
		prevbtn.on( 'click', function( e ) {
			if ( self.currentPageNum <= 1 ) {
				return;
			}

			self.gotoPage( self.currentPageNum - 1 );
			self.jumpToTop();
		} );

		nextbtn.on( 'click', function( e ) {
			if ( self.currentPageNum >= self.pageCount || self.currentPageNum == 0 ) {
				return;
			}
			self.gotoPage( self.currentPageNum + 1 );

			self.jumpToTop();
		} );

		zoominbtn.on( 'click', function( e ) {
			if ( self.zoom >= 800 ) {
				return;
			}
			self.changeZoom( 10 );
		} );

		zoomoutbtn.on( 'click', function( e ) {
			if ( self.zoom <= 20 ) {
				return;
			}
			self.changeZoom( - 10 );
		} );


		self.addMoreToolbar( toolbar );

		if ( ! fixed ) {

			divContainer.on( 'mouseenter', function( e ) {
				var htoolbar = divContainer.find( 'div.pdfemb-toolbar-hover' );
				if ( htoolbar.data( 'no-hover' ) !== true ) {
					htoolbar.show();
				}
			} );

			divContainer.on( 'mouseleave',
				function( e ) {
					var htoolbar = divContainer.find( 'div.pdfemb-toolbar-hover' );
					htoolbar.hide();
				}
			);

			divContainer.on( 'pdfembTouchTapped', function( e ) {
				e.stopPropagation();
				e.preventDefault();

				// We seem to receive two tap events in quick succession, so toggle doesn't work
				// - it just gets cancelled immediately.
				// So set a timed lock on allowing the toggle.
				if ( self.locktaps ) {
					return;
				}
				self.locktaps = true;

				var htoolbar = divContainer.find( 'div.pdfemb-toolbar-hover' );

				var wanthide = htoolbar.is( ':visible' );

				if ( htoolbar.data( 'no-hover' ) === true ) {
					wanthide = true;
				}

				if ( wanthide ) {
					htoolbar.hide();
				}
				else {
					htoolbar.show();
				}

				setTimeout( function() {
					// Release lock
					self.locktaps = false;
				}, 250 );

			} );

		}
	};

	pdfembPagesViewer.prototype.magnifyEvent = function( event ) {
		//var gtpe = $(event.originalEvent.gtpelement);
		//var divContainer = gtpe.closest('.pdfemb-viewer');
		var mag = event.originalEvent.magnification;

		if ( mag === - 1 ) {
			// End of touch
			this.resizeViewer();
			this.resizeInnerDivs();
			this.invalidateAllPages();
			this.renderPage( this.getTopVisiblePageNum() );
		}
		else {
			var offset = this.divContainer.find( '.pdfemb-pagescontainer' ).offset();
			this.magnifyZoom( mag, event.originalEvent.centreLeft - offset.left, event.originalEvent.centreTop - offset.top );
		}
	};

	pdfembPagesViewer.prototype.magnifyZoom = function( magnification, centreLeft, centreTop ) {
		var oldzoom = this.zoom;
		var newzoom = Math.floor( oldzoom * magnification );

		if ( newzoom < 20 ) {
			newzoom = 20;
		}
		if ( newzoom > 800 ) {
			newzoom = 800;
		}
		this.zoom = newzoom;
		this.divContainer.find( 'span.pdfemb-zoom' ).text( newzoom + '%' );

		this.fromZoom = oldzoom;
		this.toZoom = newzoom;

		this.pccentreLeft = centreLeft;
		this.pccentreTop = centreTop;

		this.resizeViewer();

		this.resizeInnerDivs();
		this.invalidateAllPages();

	};

	pdfembPagesViewer.prototype.pdfembWantMobile = function( wantWidth, wantHeight ) {
		return false;
	}

	pdfembPagesViewer.prototype.pdfembMakeMobile = function() {
	};

	pdfembPagesViewer.prototype.addMoreToolbar = function( toolbar ) {
	};

	pdfembPagesViewer.prototype.jumpToTop = function() {
	};

	pdfembPagesViewer.prototype.preRenderCanvas = function( ctx, pageNum, zoom ) {
	};

	core.pdfembPagesViewer = pdfembPagesViewer;
} );

function createHiDPICanvas( w, h, ratio ) {
	if ( ! ratio ) {
		ratio = PIXEL_RATIO;
	}
	var canvas = document.createElement( "canvas" );
	canvas.width = w * ratio;
	canvas.height = h * ratio;
	canvas.style.width = w + "px";
	canvas.style.height = h + "px";
	canvas.getContext( "2d" ).setTransform( ratio, 0, 0, ratio, 0, 0 );

	return canvas;
}

export const viewer = core;
