MARKUS

            #region 이미지 로딩 수정

            ViewerDataModel.Instance.ImageViewPath = await ImageSourceHelper.GetDownloadImageAsync(pageUri, pageWidth * contentScale, pageHeight * contentScale);

        public async System.Threading.Tasks.Task<BitmapImage> GetDownloadImageAsync2(Uri uri,double pageWidth,double pageHeight)

        {

            BitmapImage defaultBitmapImage = new BitmapImage();

            using (System.Net.Http.HttpClient httpClient = new System.Net.Http.HttpClient())

            {

                using (var responseStream = await httpClient.GetStreamAsync(uri))

                {

                    using (var memoryStream = new System.IO.MemoryStream())

                    {

                        await responseStream.CopyToAsync(memoryStream);

                        defaultBitmapImage.BeginInit();

                        defaultBitmapImage.CacheOption = BitmapCacheOption.OnLoad;

                        defaultBitmapImage.StreamSource = memoryStream;

                        defaultBitmapImage.DecodePixelWidth = (int)(pageWidth * (zoomAndPanControl.ContentScale * 10));

                        defaultBitmapImage.DecodePixelHeight = (int)(pageHeight * (zoomAndPanControl.ContentScale * 10));

                        defaultBitmapImage.EndInit();

                        defaultBitmapImage.Freeze();

                    }

                }

            }

            //defaultBitmapImage.Dispatcher.Invoke(() => { 

            //    defaultBitmapImage.BeginInit();

            //    defaultBitmapImage.CreateOptions = BitmapCreateOptions.IgnoreImageCache;

            //    defaultBitmapImage.CacheOption = BitmapCacheOption.OnLoad;

            //    defaultBitmapImage.UriSource = uri;

            //    defaultBitmapImage.DecodePixelWidth = Convert.ToInt32(pageWidth);

            //    defaultBitmapImage.DecodePixelHeight = Convert.ToInt32(pageHeight);// * zoomAndPanControl.ContentScale

            //    defaultBitmapImage.EndInit();

            //    ViewerDataModel.Instance.ImageViewPath = null;

            //    Logger.sendCheckLog("pageNavigator_PageChanging_BitmapImage Downloading", 1);

            //    if (defaultBitmapImage.IsDownloading)

            //    {

            //        Logger.sendCheckLog("pageNavigator_PageChanging_BitmapImage IsDownloading", 1);

            //        defaultBitmapImage.DownloadCompleted += (ex, arg) =>

            //        {

            //            defaultBitmapImage.Freeze();

            //            ViewerDataModel.Instance.ImageViewPath = defaultBitmapImage;

            //            ViewerDataModel.Instance.ImageViewWidth = pageWidth;

            //            ViewerDataModel.Instance.ImageViewHeight = pageHeight;

            //            //image dispose

            //            defaultBitmapImage = null;

            //            GC.Collect();

            //        };

            //    }

            //});

            System.Diagnostics.Debug.WriteLine("이미지 다운로드");

            return defaultBitmapImage;

        }

        private async void ZoomAndPanControl_ScaleChanged(object sender, RoutedEventArgs e)

            var pageUri = pageNavigator.CurrentPage.PageUri;

            var contentScale = zoomAndPanControl.ContentScale;

            ViewerDataModel.Instance.ImageViewPath = await ImageSourceHelper.GetDownloadImageAsync(pageUri, pageWidth * contentScale, pageHeight * contentScale);