EnumerateElements Method

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Drawing 
Imports Leadtools.Forms.DocumentWriters 
Imports Leadtools.Svg 
 
Private Shared Sub SvgDocumentEnumerateElementsExample() 
   ' The source PDF file 
   Dim sourceFile As String = "C:\LEADTOOLS21\Resources\Images\Leadtools.pdf" 
   Dim beforeSvgFile As String = "C:\LEADTOOLS21\Resources\Images\Leadtools_before.svg" 
   Dim afterSvgFile As String = "C:\LEADTOOLS21\Resources\Images\Leadtools_after.svg" 
 
   ' Assume this is our Virtual Directory 
   Dim virtualDirectory As String = "http://localhost/leadtools_images/svg/resources" 
   ' Assume this phrysical directory maps to the Virtual Directory 
   Dim physicalDirectory As String = "C:\LEADTOOLS21\Resources\Images\svg\resources" 
 
   If Not Directory.Exists(physicalDirectory) Then Directory.CreateDirectory(physicalDirectory) 
 
   ' Our SVG element enumartion callback 
   Dim callback As SvgEnumerateElementsCallback = 
      Function(document As SvgDocument, node As SvgNodeHandle, userData As Object) As Boolean 
         If node.ElementType = SvgElementType.Image Then 
            ' Get the href 
            Dim href As String = node.GetAttributeValue("xlink:href") 
            If Not String.IsNullOrEmpty(href) Then 
               ' Parse it as data URI 
               Dim dataUri As SvgDataUri = SvgDataUri.Parse(href) 
               ' Check if it is a data URI 
               If dataUri.IsDataUri Then 
                  ' Yes, create a new file in a virtual directory 
 
                  ' Show the dataURI properties 
                  Console.WriteLine("Replacing data URI") 
                  Console.WriteLine("Format:" + dataUri.ImageFormat.ToString()) 
                  If dataUri.MediaLength > 0 Then Console.WriteLine("Media:" + dataUri.Href.Substring(dataUri.MediaOffset, dataUri.MediaLength)) 
                  If dataUri.CharSetOffset > 0 Then 
                     Console.WriteLine("CharSet:" + dataUri.Href.Substring(dataUri.CharSetOffset, dataUri.CharSetLength)) 
                  Else 
                     Console.WriteLine("CharSet: not set") 
                  End If 
                  Console.WriteLine("IsBase64:" + dataUri.IsBase64.ToString()) 
                  Console.WriteLine("ImageFormat:" + dataUri.ImageFormat.ToString()) 
                  Dim extension As String = dataUri.Extension 
                  Console.WriteLine("Extension:" + dataUri.Extension) 
 
                  ' Get a file name 
                  Dim name As String = Guid.NewGuid().ToString().Replace("-", "") + "." + dataUri.Extension 
 
                  ' Save it 
                  ' Full physical path 
                  Dim filePath As String = Path.Combine(physicalDirectory, name) 
                  dataUri.DecodeToFile(filePath) 
 
                  ' Alternatively you can save the data yourself using this code 
                  ' Dim data As String = dataUri.Href.Substring(dataUri.ValueOffset, dataUri.ValueLength) 
                  ' ' Save the data 
                  ' Dim base64String As String = dataUri.Href.Substring(dataUri.ValueOffset, dataUri.ValueLength) 
                  ' Dim rowData() As Byte = Convert.FromBase64String(base64String) 
                  ' 
                  ' ' Save it to disk 
                  ' File.WriteAllBytes(filePath, rawData) 
 
                  ' Finally replace the attribute in the image element with the URI 
                  Dim virtualPath As String = virtualDirectory + "/" + name 
                  node.SetAttributeValue("xlink:href", virtualPath) 
               Else 
                  Console.WriteLine("Does not contain a valid data URI.") 
               End If 
            End If 
         End If 
         Return True 
 
      End Function 
 
   Using rasterCodecs As New RasterCodecs() 
      ' Use 300 DPI when loading document images 
      rasterCodecs.Options.RasterizeDocument.Load.Resolution = 300 
 
      ' Load the first page as SVG 
      Using svg As SvgDocument = CType(rasterCodecs.LoadSvg(sourceFile, 1, Nothing), SvgDocument) 
         If Not svg.IsFlat Then svg.Flat(Nothing) 
         If Not svg.Bounds.IsValid Then svg.CalculateBounds(False) 
 
         ' Save this SVG to disk, report the size 
         svg.SaveToFile(beforeSvgFile, Nothing) 
         Console.WriteLine("Before unembedding the image, size is " + New FileInfo(beforeSvgFile).Length.ToString()) 
 
         ' Now enumerate the elements to replace each embedded image with a URL 
         ' Since we are going to modify the SVG, call BeginUpdate/EndUpdate to speed up the process 
         svg.BeginUpdate() 
         Dim enumerationOptions As New SvgEnumerateOptions 
         enumerationOptions.EnumerateDirection = SvgEnumerateDirection.TopToBottom 
         svg.EnumerateElements(enumerationOptions, callback, Nothing) 
         svg.EndUpdate() 
 
         ' Save this SVG to disk again, report the size, should be alot smaller since the image are unembedded and stored as external resources 
         svg.SaveToFile(afterSvgFile, Nothing) 
         Console.WriteLine("Before unembedding the image, size is " + New FileInfo(afterSvgFile).Length.ToString()) 
      End Using 
   End Using 
End Sub