Go Requires Chilkat v11.7.0+

Tile a Watermark Across a PDF Page

See more PDF Watermark Examples

Demonstrates a tiled watermark, which repeats the stamp over the whole page instead of placing it once. Tiling overrides position.align; tile.spacingX and spacingY set the gaps, and tile.stagger offsets alternate rows by half a tile so the pattern does not line up in columns. A faint tiled stamp carrying the name or address is the usual way to mark a document so that a leaked copy can be traced back, and zOrder back keeps it behind the text where it does not hinder reading. 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 long_report.pdf

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

    json := chilkat.NewJsonObject()
    json.UpdateString("type","text")

    //  {date:FORMAT} is replaced per page when the watermark is added.  The other placeholders are
    //  {page}, {pages} and {filename}; {{ gives a literal brace.
    json.UpdateString("text","jdoe@example.com  {date:yyyy-MM-dd}")
    json.UpdateString("id","trace")
    json.UpdateString("zOrder","back")
    json.UpdateNumber("font.size","14")
    json.UpdateNumber("opacity","0.15")
    json.UpdateNumber("rotation","30")

    json.UpdateBool("tile.enabled",true)
    json.UpdateNumber("tile.spacingX","60")
    json.UpdateNumber("tile.spacingY","80")
    json.UpdateBool("tile.stagger",true)

    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("id: ", *jsonOut.StringOf("id"), " pages: ", *jsonOut.StringOf("pages"))

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

    //  Sample output:

    //  id: trace pages: 1-3

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