VB.NET Requires Chilkat v11.7.0+

Audit a PDF First, Optimize Only If It Is Worth It

See more PDF Optimization Examples

Demonstrates deciding whether to rewrite a PDF at all. "audit" costs a fraction of a second and changes nothing, so a batch job can audit every file and optimize only those where enough would be saved. Here the threshold is a tenth of the file; a file already as small as it can be is left alone. 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 watersense_accomplishments.pdf

Dim pdf As New Chilkat.Pdf
success = pdf.LoadFile("qa_data/pdf/watersense_accomplishments.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


Dim json As New Chilkat.JsonObject
Dim jsonOut As New Chilkat.JsonObject
success = pdf.Optimize("audit",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


Dim fileSize As Integer = jsonOut.IntOf("fileSize")
Dim estimated As Integer = jsonOut.IntOf("estimatedSavings.total")
Debug.WriteLine("fileSize:  " & fileSize)
Debug.WriteLine("estimated: " & estimated)

'  Only bother when at least a tenth of the file would go.
If (estimated > (fileSize / 10)) Then
    Debug.WriteLine("Worth optimizing.")
    success = pdf.Optimize("optimize",json,jsonOut)
    If (success = False) Then
        Debug.WriteLine(pdf.LastErrorText)
        Exit Sub
    End If

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

    Debug.WriteLine("bytesSaved: " & jsonOut.IntOf("bytesSaved"))
Else
    Debug.WriteLine("Already small enough; left as it is.")
End If