PowerShell Requires Chilkat v11.7.0+

Remove PDF Objects Nothing Refers To

See more PDF Optimization Examples

Demonstrates removeUnreferenced. When a page, an image or a whole section is replaced in an editor, the objects it used often stay in the file with nothing pointing at them any more. They are not old revisions -- they are in the current revision, simply unreachable -- so only a reachability walk from the document catalog finds them. In a publication assembled over several editing passes this is frequently the largest single saving. PowerShell

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $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

$pdf = New-Object Chilkat.Pdf
$success = $pdf.LoadFile("qa_data/pdf/watersense_accomplishments.pdf")
if ($success -eq $false) {
    $($pdf.LastErrorText)
    exit
}

$json = New-Object Chilkat.JsonObject
$jsonOut = New-Object Chilkat.JsonObject
$success = $pdf.Optimize("audit",$json,$jsonOut)
if ($success -eq $false) {
    $($pdf.LastErrorText)
    exit
}

$("fileSize: " + $jsonOut.IntOf("fileSize"))
$("removeUnreferenced would save: " + $jsonOut.IntOf("estimatedSavings.removeUnreferenced"))

#  Optimize with the defaults and see how many objects were actually dropped.
$success = $pdf.Optimize("optimize",$json,$jsonOut)
if ($success -eq $false) {
    $($pdf.LastErrorText)
    exit
}

$success = $pdf.WriteFile("qa_output/watersense_optimized.pdf")
if ($success -eq $false) {
    $($pdf.LastErrorText)
    exit
}

$("objects removed: " + $jsonOut.IntOf("actions.removeUnreferenced.count"))
$("bytes saved:     " + $jsonOut.IntOf("actions.removeUnreferenced.bytesSaved"))

#  Nothing a page needs is ever removed: the walk starts at the document catalog and follows every
#  reference, including the ones in annotations, the structure tree, named destinations and the
#  optional-content configuration.
$("pages after: " + $pdf.NumPages)