Go Requires Chilkat v11.7.0+

Replace the Value After a Label in a PDF (Re-issue an Invoice)

See more PDF Text Replacement Examples

Demonstrates replacing the values that follow labels such as "Invoice Number:" on a PDF that has no placeholders -- an ordinary invoice. Each entry of the "labels" array names a label as it appears on the page and the new value; the value replaces the rest of the label's line. Label matching ignores case, extra spaces and a trailing colon. The replaced text is read back with ExtractText to confirm it. 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 invoice_labels.pdf

    pdf := chilkat.NewPdf()
    success = pdf.LoadFile("qa_data/pdf/invoice_labels.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        return
    }

    //  The invoice has lines such as "Invoice Number:   INV-2026-0412" and "Total Due:  $1,234.53".
    //  Each label's new value replaces whatever follows the label on its line.
    json := chilkat.NewJsonObject()
    json.UpdateString("labels[0].label","Invoice Number:")
    json.UpdateString("labels[0].value","INV-2026-0500")
    json.UpdateString("labels[1].label","Invoice Date:")
    json.UpdateString("labels[1].value","April 2, 2026")
    json.UpdateString("labels[2].label","customer")
    json.UpdateString("labels[2].value","Contoso Ltd")
    json.UpdateString("labels[3].label","Total Due:")
    json.UpdateString("labels[3].value","$1,999.99")

    jsonOut := chilkat.NewJsonObject()
    success = pdf.TextReplace("apply",json,jsonOut)
    if success == false {
        fmt.Println("Not applied: ", *jsonOut.Emit())
        if success == false {
            fmt.Println(pdf.LastErrorText())
            pdf.DisposePdf()
            json.DisposeJsonObject()
            jsonOut.DisposeJsonObject()
            return
        }

    }

    i := 0
    count_i := jsonOut.SizeOfArray("replacements")
    for i < count_i {
        jsonOut.SetI(i)
        fmt.Println("Replaced the value of \"", *jsonOut.StringOf("replacements[i].label"), "\" on page ", *jsonOut.StringOf("replacements[i].pages"))
        i = i + 1
    }

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

    //  Read the new values back with ExtractText's label option.
    jsonRead := chilkat.NewJsonObject()
    jsonText := chilkat.NewJsonObject()
    jsonRead.UpdateString("label","Total Due")
    jsonRead.UpdateString("labelValue","right")
    success = pdf.ExtractText("text",jsonRead,jsonText)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        jsonRead.DisposeJsonObject()
        jsonText.DisposeJsonObject()
        return
    }

    fmt.Println("Total Due is now: ", *jsonText.StringOf("text"))

    //  Sample output:

    //  Replaced the value of "Invoice Number:" on page 1
    //  Replaced the value of "Invoice Date:" on page 1
    //  Replaced the value of "customer" on page 1
    //  Replaced the value of "Total Due:" on page 1
    //  Total Due is now: $1,999.99

    pdf.DisposePdf()
    json.DisposeJsonObject()
    jsonOut.DisposeJsonObject()
    jsonRead.DisposeJsonObject()
    jsonText.DisposeJsonObject()