egtbeamwall/EgtBEAMWALL.ViewerOptimizer/PdfViewer/PdfViewer.xaml.vb

Imports System.IO
Imports System.Threading.Tasks
Imports Windows.Data.Pdf
Imports Windows.Storage
Imports Windows.Storage.Streams

Partial Public Class PdfViewer
   Inherits UserControl

   'Public Property PdfPath As String
   '   Get
   '      Return CStr(GetValue(PdfPathProperty))
   '   End Get
   '   Set(value As String)
   '      SetValue(PdfPathProperty, value)
   '   End Set
   'End Property

   'Private Shared m_Items As New List(Of Image)
   'Public Shared ReadOnly Property Items As List(Of Image)
   '   Get
   '      Return m_Items
   '   End Get
   'End Property

   Public Property PdfPath As String
      Get
         Return CStr(GetValue(PdfPathProperty))
      End Get
      Set(value As String)
         SetValue(PdfPathProperty, value)
      End Set
   End Property

   'Public Shared ReadOnly PdfPathProperty As DependencyProperty = DependencyProperty.Register("PdfPath",
   '                                                                                           GetType(String),
   '                                                                                           GetType(PdfViewer),
   '                                                                                           New FrameworkPropertyMetadata(String.Empty, New PropertyChangedCallback(AddressOf OnPdfPathChanged)))

   Public Shared ReadOnly PdfPathProperty As DependencyProperty = DependencyProperty.Register("PdfPath",
                                                                                              GetType(String),
                                                                                              GetType(PdfViewer),
                                                                                              New PropertyMetadata(Nothing, propertyChangedCallback:=AddressOf OnPdfPathChanged))

   Private Shared Sub OnPdfPathChanged(d As DependencyObject, e As DependencyPropertyChangedEventArgs)
      Dim pdfDrawer As PdfViewer = CType(d, PdfViewer)

      If Not String.IsNullOrEmpty(pdfDrawer.PdfPath) Then
         Dim path = System.IO.Path.GetFullPath(pdfDrawer.PdfPath)
         StorageFile.GetFileFromPathAsync(path).AsTask().ContinueWith(Function(t) PdfDocument.LoadFromFileAsync(t.Result).AsTask()).Unwrap().ContinueWith(Function(t2) PdfToImages(pdfDrawer, t2.Result), TaskScheduler.FromCurrentSynchronizationContext())
      End If
   End Sub

   'Private Shared Sub OnPdfPathChanged(d As DependencyObject, e As DependencyPropertyChangedEventArgs)
   '   Dim pdfDrawer As PdfViewer = CType(d, PdfViewer)
   '   If Not String.IsNullOrEmpty(pdfDrawer.PdfPath) Then
   '      Dim path = System.IO.Path.GetFullPath(pdfDrawer.PdfPath)
   '      StorageFile.GetFileFromPathAsync(path).AsTask().ContinueWith(Function(t) PdfDocument.LoadFromFileAsync(t.Result).AsTask()).Unwrap().ContinueWith(Function(t2) PdfToImages(t2.Result), TaskScheduler.FromCurrentSynchronizationContext())
   '   End If
   'End Sub

   Sub New()
      InitializeComponent()
   End Sub

   '''' <summary>
   '''' Funzione che trasforma le pagine del pdf in immagine
   '''' </summary>
   '''' <param name="pdfDoc">Singola pagina del PDf</param>
   '''' <returns></returns>
   'Private Shared Async Function PdfToImages(pdfDoc As PdfDocument) As Task
   '   'Dim items As ItemCollection = pdfViewer.PagesContainer.Items
   '   Items.Clear()

   '   If IsNothing(pdfDoc) Then Return

   '   For i As Integer = 0 To pdfDoc.PageCount - 1
   '      Using page As PdfPage = pdfDoc.GetPage(i)
   '         Dim bitmap As BitmapImage = Await PageToBitmapAsync(page)
   '         Dim image As New Image With {
   '             .Source = bitmap,
   '             .HorizontalAlignment = HorizontalAlignment.Center,
   '             .Width = bitmap.Width,
   '             .Height = bitmap.Height
   '         }
   '         Items.Add(image)
   '      End Using
   '   Next
   'End Function

   ''' <summary>
   ''' Funzione che trasforma le pagine del pdf in immagine
   ''' </summary>
   ''' <param name="pdfViewer">PDF da trasformare</param>
   ''' <param name="pdfDoc">Singola pagina del PDf</param>
   ''' <returns></returns>
   Private Shared Async Function PdfToImages(pdfViewer As PdfViewer, pdfDoc As PdfDocument) As Task
      Dim items As ItemCollection = pdfViewer.PagesContainer.Items
      items.Clear()

      If IsNothing(pdfDoc) Then Return

      For i As Integer = 0 To pdfDoc.PageCount - 1
         Using page As PdfPage = pdfDoc.GetPage(i)
            Dim bitmap As BitmapImage = Await PageToBitmapAsync(page)
            Dim image As New Image With {
                .Source = bitmap,
                .HorizontalAlignment = HorizontalAlignment.Center,
                .Width = bitmap.Width,
                .Height = bitmap.Height,
                .Margin = New Thickness(5, 20, 5, 20)
            }
            items.Add(image)
         End Using
      Next
   End Function

   ''' <summary>
   ''' Funzione che trasforma la singola pagina del PDF in bitmap
   ''' </summary>
   ''' <param name="page">Singola pagina del PDF che verrà trasformata in bitmap</param>
   ''' <returns></returns>
   Private Shared Async Function PageToBitmapAsync(page As PdfPage) As Task(Of BitmapImage)
      Dim image As New BitmapImage()

      Using stream = New InMemoryRandomAccessStream()
         Await page.RenderToStreamAsync(stream)
         image.BeginInit()
         image.CacheOption = BitmapCacheOption.OnLoad
         image.StreamSource = stream.AsStream()
         image.EndInit()
      End Using

      Return image
   End Function
End Class