Read MetaData from a TIFF image

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  YuriG

  August 2022 Answer ✓

  Hi Friedrich,
  
  Image-Pro doesn't expose API to read tiff tags, but you can use existing .NET classes, such as Bitmap to read TIFF TAGs.
  
  I've attached the project that reads all TIFF tags of the active image. The code looks like this:
  
  

      ''' Read all TIFF tags from active image
      Public Sub ReadTIFFTagsFromActiveImage
          Dim doc As IMcDocument=ThisApplication.ActiveDocument
          If doc Is Nothing Then Exit Sub
          Dim filename As String=doc.FileName
          ThisApplication.Output.Show
          ThisApplication.Output.Clear
          ThisApplication.Output.PrintMessage($"File name = {filename}")
          If Not System.IO.Path.GetExtension(filename).ToLower.Contains("tif") Then Exit Sub
  
          Dim bp As System.Drawing.Bitmap = New System.Drawing.Bitmap(filename)
          Dim bpProps() As System.Drawing.Imaging.PropertyItem = bp.PropertyItems
  
          Dim pName As String = String.Empty, pVal As New Object
          For Each p As System.Drawing.Imaging.PropertyItem In bpProps
              If GetPropertyDetail(p, pName, pVal) Then
                  ThisApplication.Output.PrintMessage($"Property ({pName}) = {pVal.ToString} ")
              Else
                  ThisApplication.Output.PrintMessage($"Property ({pName}), Type = {p.Type} Len = {p.Len}")
              End If
          Next
      End Sub
  
      Private Function GetPropertyDetail(ByVal p As System.Drawing.Imaging.PropertyItem, ByRef propName As String, ByRef propValue As Object) As Boolean
          Dim success As Boolean = True
          ' Hard-coded values from TIFF specification 
          Select Case p.Id
              Case 256
                  propName = "ImageWidth"
                  propValue = ExtractValue(p, True)
              Case 257
                  propName = "ImageWidth"
                  propValue = ExtractValue(p, True)
              Case 269
                  propName = "DocumentName"
                  propValue = ExtractValue(p, True)
              Case 270
                  propName = "ImageDescription"
                  propValue = ExtractValue(p, True)
              Case Else
                  propName = "unkown (Id = " & p.Id.ToString() & ")"
                  propValue = Nothing
                  success = False
          End Select
  
          Return success
  
      End Function
  
      Private Function ExtractValue(ByVal p As System.Drawing.Imaging.PropertyItem, ByVal AsSingle As Boolean) As Object
          Select Case p.Type
              Case 2  ' Null-terminated ASCII string
                  Return System.Text.Encoding.ASCII.GetString(p.Value, 0, p.Len - 1)
  
              Case 3  ' Array of unsigned short (16-bit) integers.
                  Dim ms As New System.IO.MemoryStream(p.Value)
                  Dim bReader As New System.IO.BinaryReader(ms)
                  Dim uIntList As New System.Collections.Generic.List(Of System.UInt16)
                  Do Until ms.Position >= ms.Length - 1
                      uIntList.Add(bReader.ReadUInt16)
                  Loop
                  If AsSingle Then
                      Return uIntList(0)
                  Else
                      Return uIntList.ToArray()
                  End If
  
              Case Else
                  Return ("Conversion not defined for type " & p.Type.ToString())
          End Select
      End Function
  

  The result is printed to the Output window:
  
  
  
  The code is based on this example. The PropertyItem class is defined here. 
  You can extend the macro to read your specific tags.
  
  Regards, 
  
  Yuri

  TiffTagsReader.ipx 1.6K

  0