How to increase speed of pdf rendering via PDF API?

Question

I use FlipView to show pdf pages. I found PDF rendering is so slow when render each page.I written in C# only.
(I follow sample: http://code.msdn.microsoft.com/windowsapps/PDF-viewer-sample-85a4bb30)

I found this sample: http://msdn.microsoft.com/en-us/library/windows/apps/dn263107.aspx . Pdf rendering is so fast.
But library in this sample written in C++. I try to adpat with my program , but i can't. it's difficult c++ for me.

Please suggest me to adpat Pdf C++ library to have below feature:
- Redering selected page.
- Pdf size change when page changed (Now , the sample can't do it)
- FlipView ItemsTemplate can be changed (one or two pages show)

Thanks.

Answer 1

Did you modify the C# sample at all? If so, please post it here for us to review.

---

Matt Small - Microsoft Escalation Engineer - Forum Moderator
If my reply answers your question, please mark this post as answered.

NOTE: If I ask for code, please provide something that I can drop directly into a project and run (including XAML), or an actual application project. I'm trying to help a lot of people, so I don't have time to figure out weird snippets with undefined objects and unknown namespaces.

Answer 2

Here you are.

MainPage.xaml

<Page
    x:Class="PdfSample.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:PdfSample"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <FlipView x:Name="xFlipView">
            <FlipView.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <Image Source="{Binding Image}" HorizontalAlignment="Center" Height="{Binding Height}" Width="{Binding Width}"></Image>                      
                    </Grid>
                </DataTemplate>
            </FlipView.ItemTemplate>
            <FlipView.ItemsPanel>
                <ItemsPanelTemplate>
                    <VirtualizingStackPanel AreScrollSnapPointsRegular="True" Orientation="Horizontal" CleanUpVirtualizedItemEvent="VirtualizingStackPanel_CleanUpVirtualizedItemEvent" />
                </ItemsPanelTemplate>
            </FlipView.ItemsPanel>
        </FlipView>
    </Grid>
</Page>

MainPage.xaml.cs

 public sealed partial class MainPage : Page
    {
        ObservableCollection<FData> items = new ObservableCollection<FData>();

        public MainPage()
        {
            this.InitializeComponent();
        }

        protected override async void OnNavigatedTo(NavigationEventArgs e)
        {          
            StorageFolder installedLocation = Package.Current.InstalledLocation;
            var pdfFile = await installedLocation.GetFileAsync("Assets\\magazine.pdf");
            var pdfDocument = await PdfDocument.LoadFromFileAsync(pdfFile);
            for (int i = 0; i < pdfDocument.PageCount; i++)
            {
                items.Add(new FData() { PageNumber = i ,PdfDoc = pdfDocument ,Width = Window.Current.Bounds.Width,Height = Window.Current.Bounds.Height});
            }
            xFlipView.ItemsSource = items;
        }

        private void VirtualizingStackPanel_CleanUpVirtualizedItemEvent(object sender, CleanUpVirtualizedItemEventArgs e)
        {
            var item = e.Value as FData;
            item.Dispose();
        }
    }


    public class FData : INotifyPropertyChanged
    {
        
        public int PageNumber { get; set; }
        public PdfDocument PdfDoc { get; set; }
        public double Height { get; set; }
        public double Width { get; set; }
        private ImageSource _image = null;
        public ImageSource Image 
        {
            get 
            {
                if (_image == null)
                    Rendering();
                return _image;
            }
            set 
            {
                _image = value;
            }
        }

        private async void Rendering()
        {
            using (var page = PdfDoc.GetPage((uint)PageNumber)) 
            {
                var renderOption = new PdfPageRenderOptions();
                var img = new BitmapImage();
                renderOption.DestinationHeight = (uint)(Height);              
                InMemoryRandomAccessStream stream = new InMemoryRandomAccessStream();               
                await page.RenderToStreamAsync(stream, renderOption);               
                img.SetSource(stream);
                _image = img;
                if (PropertyChanged != null)
                    PropertyChanged(this, new PropertyChangedEventArgs("Image"));
                _image = null;
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        internal void Dispose()
        {
            _image = null;
        }
    }