Go 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. Go

    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 grand_canyon_hiking_guide.pdf

    fac := chilkat.NewFileAccess()
    json := chilkat.NewJsonObject()
    jsonOut := chilkat.NewJsonObject()

    //  generate: pack the objects (the default).
    pdf1 := chilkat.NewPdf()
    success = pdf1.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf")
    if success == false {
        fmt.Println(pdf1.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        return
    }

    json.UpdateString("objectStreams","generate")
    success = pdf1.Optimize("optimize",json,jsonOut)
    if success == false {
        fmt.Println(pdf1.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        return
    }

    success = pdf1.WriteFile("qa_output/grand_canyon_objstm_generate.pdf")
    if success == false {
        fmt.Println(pdf1.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        return
    }

    fmt.Println("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.
    pdf2 := chilkat.NewPdf()
    success = pdf2.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf")
    if success == false {
        fmt.Println(pdf2.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        pdf2.DisposePdf()
        return
    }

    json.UpdateString("objectStreams","disable")
    success = pdf2.Optimize("optimize",json,jsonOut)
    if success == false {
        fmt.Println(pdf2.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        pdf2.DisposePdf()
        return
    }

    success = pdf2.WriteFile("qa_output/grand_canyon_objstm_disable.pdf")
    if success == false {
        fmt.Println(pdf2.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        pdf2.DisposePdf()
        return
    }

    fmt.Println("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.
    pdf3 := chilkat.NewPdf()
    success = pdf3.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf")
    if success == false {
        fmt.Println(pdf3.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        pdf2.DisposePdf()
        pdf3.DisposePdf()
        return
    }

    json.UpdateString("objectStreams","preserve")
    success = pdf3.Optimize("optimize",json,jsonOut)
    if success == false {
        fmt.Println(pdf3.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        pdf2.DisposePdf()
        pdf3.DisposePdf()
        return
    }

    success = pdf3.WriteFile("qa_output/grand_canyon_objstm_preserve.pdf")
    if success == false {
        fmt.Println(pdf3.LastErrorText())
        fac.DisposeFileAccess()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf1.DisposePdf()
        pdf2.DisposePdf()
        pdf3.DisposePdf()
        return
    }

    fmt.Println("preserve: ", fac.FileSize("qa_output/grand_canyon_objstm_preserve.pdf"), " bytes")

    fac.DisposeFileAccess()
    json.DisposeJsonObject()
    jsonOut.DisposeJsonObject()
    pdf1.DisposePdf()
    pdf2.DisposePdf()
    pdf3.DisposePdf()