handle different page size in pdf viewer

services/web/public/coffee/ide/pdfng/directives/pdfPage.coffee

@@ -38,6 +38,7 @@ define [
 					text: textElement
 					annotations: annotationsElement
 					highlights: highlightsElement
+					container: element
 				}
 
 				if !scope.page.sized

services/web/public/coffee/ide/pdfng/directives/pdfRenderer.coffee

@@ -25,6 +25,7 @@ define [
 					pdfDocument.getDownloadInfo().then () =>
 						@options.loadedCallback()
 				@errorCallback = @options.errorCallback
+				@pageSizeChangeCallback = @options.pageSizeChangeCallback
 				@pdfjs.catch (exception) =>
 					# console.log 'ERROR in get document', exception
 					@errorCallback(exception)
@@ -216,8 +217,14 @@ define [
 				canvas.height(newHeight + 'px')
 				canvas.width(newWidth + 'px')
 
-				element.canvas.height(newHeight)
-				element.canvas.width(newWidth)
+				oldHeight = element.canvas.height()
+				oldWidth = element.canvas.width()
+				if newHeight != oldHeight  or  newWidth != oldWidth
+					element.canvas.height(newHeight + 'px')
+					element.canvas.width(newWidth + 'px')
+					element.container.height(newHeight + 'px')
+					element.container.width(newWidth + 'px')
+					@pageSizeChangeCallback?(pagenum, newHeight - oldHeight)
 
 				if pixelRatio != 1
 					ctx.scale(pixelRatio, pixelRatio)

services/web/public/coffee/ide/pdfng/directives/pdfViewer.coffee

@@ -40,6 +40,8 @@ define [
 				errorCallback: (error) ->
 					Raven.captureMessage?('pdfng error ' + error)
 					$scope.$emit 'pdf:error', error
+				pageSizeChangeCallback: (pageNum, deltaH) ->
+					$scope.$broadcast 'pdf:page:size-change', pageNum, deltaH
 			})
 
 			# we will have all the main information needed to start display
@@ -336,6 +338,16 @@ define [
 					# trigger a redraw
 					scope.scale = angular.copy (scope.scale)
 
+				scope.$on 'pdf:page:size-change', (event, pageNum, delta) ->
+					#console.log 'page size change event', pageNum, delta
+					origposition = angular.copy scope.position
+					#console.log 'orig position', JSON.stringify(origposition)
+					if pageNum - 1 < origposition.page && delta != 0
+						currentScrollTop =  element.scrollTop()
+						console.log 'adjusting scroll from', currentScrollTop, 'by', delta
+						scope.adjustingScroll = true
+						element.scrollTop(currentScrollTop + delta)
+
 				element.on 'scroll', () ->
 					#console.log 'scroll event', element.scrollTop(), 'adjusting?', scope.adjustingScroll
 					#scope.scrollPosition = element.scrollTop()