private void CreateThumbnailSurface()
{
const uint scaleFactor = 8;
var rawPixelsPerViewPixel = DisplayInformation.GetForCurrentView().RawPixelsPerViewPixel;
var pageWidth = Page.Width / rawPixelsPerViewPixel;
var pageHeight = Page.Height / rawPixelsPerViewPixel;
var pageViewSize = new Size(pageWidth / scaleFactor, pageHeight / scaleFactor);
_thumbnailSis = new SisPageRenderer(Page, pageViewSize);
var thumbnailBackgroundBrush = new ImageBrush
{
ImageSource = _thumbnailSis.Source
};
thumbnailContentCanvas.Background = thumbnailBackgroundBrush;
}
private void CleanUp()
{
if (_pageViewObserver != null)
{
_pageViewObserver.ZoomFactorChanging -= HandleZoomFactorChanging;
_pageViewObserver.ZoomFactorChanged -= HandleZoomFactorChanged;
_pageViewObserver = null;
}
if (_contentVsis != null)
{
_contentVsis.Dispose();
_contentVsis = null;
}
_thumbnailSis = null;
thumbnailContentCanvas.Background = null;
contentCanvas.Background = null;
contentCanvas.Children.Clear();
Page = null;
TextLayer = null;
}
