B4X Requires Chilkat v11.7.0+

PDF Object Streams: generate, preserve or disable

See more PDF Optimization Examples

Demonstrates the objectStreams option. An object stream packs many small objects (dictionaries, not stream data) into one compressed stream, which is usually a worthwhile saving in a document with many pages or tags. "generate" (the default) packs them and writes a cross-reference stream; "preserve" keeps the file as it is -- packed if it already was, not packed if it was not; "disable" writes every object on its own with a classic cross-reference table, which is what a PDF 1.4 reader needs. Object streams require PDF 1.5 and are skipped for PDF/A-1. B4X

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 grand_canyon_hiking_guide.pdf

Dim fac As ChilkatFileAccess
fac.Initialize
Dim json As ChilkatJsonObject
json.Initialize
Dim jsonOut As ChilkatJsonObject
jsonOut.Initialize

'  generate: pack the objects (the default).
Dim pdf1 As ChilkatPdf
pdf1.Initialize("pdf1")
success = pdf1.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf")
If success = False Then
    Log(pdf1.LastErrorText)
    Return
End If

json.UpdateString("objectStreams", "generate")
success = pdf1.Optimize("optimize", json, jsonOut)
If success = False Then
    Log(pdf1.LastErrorText)
    Return
End If

success = pdf1.WriteFile("qa_output/grand_canyon_objstm_generate.pdf")
If success = False Then
    Log(pdf1.LastErrorText)
    Return
End If

Log("generate: " & fac.FileSize("qa_output/grand_canyon_objstm_generate.pdf") & " bytes, objects packed: " & jsonOut.IntOf("actions.objectStreams.count"))

'  disable: every object on its own, with a classic cross-reference table.
Dim pdf2 As ChilkatPdf
pdf2.Initialize("pdf2")
success = pdf2.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf")
If success = False Then
    Log(pdf2.LastErrorText)
    Return
End If

json.UpdateString("objectStreams", "disable")
success = pdf2.Optimize("optimize", json, jsonOut)
If success = False Then
    Log(pdf2.LastErrorText)
    Return
End If

success = pdf2.WriteFile("qa_output/grand_canyon_objstm_disable.pdf")
If success = False Then
    Log(pdf2.LastErrorText)
    Return
End If

Log("disable:  " & fac.FileSize("qa_output/grand_canyon_objstm_disable.pdf") & " bytes")

'  preserve: leave the file's own structure alone.  Use it when the output must stay readable by
'  whatever reads the input today.
Dim pdf3 As ChilkatPdf
pdf3.Initialize("pdf3")
success = pdf3.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf")
If success = False Then
    Log(pdf3.LastErrorText)
    Return
End If

json.UpdateString("objectStreams", "preserve")
success = pdf3.Optimize("optimize", json, jsonOut)
If success = False Then
    Log(pdf3.LastErrorText)
    Return
End If

success = pdf3.WriteFile("qa_output/grand_canyon_objstm_preserve.pdf")
If success = False Then
    Log(pdf3.LastErrorText)
    Return
End If

Log("preserve: " & fac.FileSize("qa_output/grand_canyon_objstm_preserve.pdf") & " bytes")