Go Requires Chilkat v11.7.0+

Page Numbers, Dates and the File Name in a PDF Watermark

See more PDF Watermark Examples

Demonstrates the placeholders a text watermark understands, each replaced per page as the watermark is added: {page} is the page number, {pages} the page count, {date:FORMAT} the current local date and time, and {filename} the name of the file that was loaded. Two braces give a literal brace. pageNumber.start sets what {page} is on the first page, which is how a numbering that ignores a cover is produced, and pageNumber.style formats both {page} and {pages} as decimal, romanUpper, romanLower, letterUpper or letterLower. 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 four_pages.pdf

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

    json := chilkat.NewJsonObject()
    json.UpdateString("type","text")
    json.UpdateString("text","Page {page} of {pages}  -  printed {date:yyyy-MM-dd HH:mm}  -  {filename}")
    json.UpdateString("id","pagefoot")
    json.UpdateString("position.align","bottom")
    json.UpdateNumber("position.margin","24")
    json.UpdateNumber("font.size","9")
    json.UpdateString("color","#505050")

    jsonOut := chilkat.NewJsonObject()
    success = pdf.Watermark("add",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("footer pages: ", *jsonOut.StringOf("pages"))

    //  Roman numerals that start at i on page 2, so that a cover page is not numbered.
    pdf2 := chilkat.NewPdf()
    success = pdf2.LoadFile("qa_data/pdf/four_pages.pdf")
    if success == false {
        fmt.Println(pdf2.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf2.DisposePdf()
        return
    }

    json2 := chilkat.NewJsonObject()
    json2.UpdateString("type","text")
    json2.UpdateString("text","- {page} -")
    json2.UpdateString("id","roman")
    json2.UpdateString("pages","2-")
    json2.UpdateInt("pageNumber.start",1)
    json2.UpdateString("pageNumber.style","romanLower")
    json2.UpdateString("position.align","bottom")
    json2.UpdateNumber("font.size","10")
    success = pdf2.Watermark("add",json2,jsonOut)
    if success == false {
        fmt.Println(pdf2.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf2.DisposePdf()
        json2.DisposeJsonObject()
        return
    }

    fmt.Println("roman pages: ", *jsonOut.StringOf("pages"))

    success = pdf.WriteFile("qa_output/four_pages_numbered.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf2.DisposePdf()
        json2.DisposeJsonObject()
        return
    }

    //  Sample output:

    //  footer pages: 1-4
    //  roman pages: 2-4

    pdf.DisposePdf()
    json.DisposeJsonObject()
    jsonOut.DisposeJsonObject()
    pdf2.DisposePdf()
    json2.DisposeJsonObject()