VB.NET Requires Chilkat v11.7.0+

Optimizing an Encrypted PDF

See more PDF Optimization Examples

Demonstrates optimizing a PDF that is encrypted. Set the password before loading, exactly as for any other operation; the optimized PDF keeps the security it had, so the output still needs the same password. Because Chilkat honours the permissions recorded in the document, optimizing requires owner rights or the "modify" permission: a PDF opened with a user password that forbids modification can be audited but not optimized. VB.NET

Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  The PDF used in this example is available at encrypted_user_password.pdf

Dim pdf As New Chilkat.Pdf

'  The password must be set before loading.
pdf.UserPassword = "secret"
success = pdf.LoadFile("qa_data/pdf/encrypted_user_password.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


'  What security does the file have, and may it be modified?
Dim json As New Chilkat.JsonObject
Dim jsonOut As New Chilkat.JsonObject
success = pdf.Protection("getInfo",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("encrypted: " & jsonOut.BoolOf("loaded.encrypted"))
Debug.WriteLine("method:    " & jsonOut.StringOf("loaded.method"))
Debug.WriteLine("openedWith: " & jsonOut.StringOf("loaded.openedWith"))
Debug.WriteLine("may modify: " & jsonOut.BoolOf("loaded.permissions.modify"))

success = pdf.Optimize("optimize",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

success = pdf.WriteFile("qa_output/encrypted_optimized.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("bytesSaved: " & jsonOut.IntOf("bytesSaved"))

'  The output is still encrypted with the same security: loading it without the password fails.
Dim noPassword As New Chilkat.Pdf
success = noPassword.LoadFile("qa_output/encrypted_optimized.pdf")
Dim q As New Chilkat.JsonObject
Dim qOut As New Chilkat.JsonObject
success = noPassword.ExtractText("assess",q,qOut)
Debug.WriteLine("passwordRequired without the password: " & qOut.BoolOf("quality.passwordRequired"))

'  With the password it reads normally.
Dim withPassword As New Chilkat.Pdf
withPassword.UserPassword = "secret"
success = withPassword.LoadFile("qa_output/encrypted_optimized.pdf")
If (success = False) Then
    Debug.WriteLine(withPassword.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("pages: " & withPassword.NumPages)