Swift Requires Chilkat v11.7.0+

PDF Placeholders Without a Value: Error, Blank or Keep

See more PDF Text Replacement Examples

Demonstrates the "unusedPlaceholders" option, which decides what happens to a placeholder found on the page that has no value in "placeholders": "error" (the default) makes it a problem with the reason unusedPlaceholder, so nothing is applied; "blank" replaces it with nothing; "keep" leaves it on the page as it is. Swift

func chilkatTest() {
    var success: Bool = 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_template.pdf

    let pdf = CkoPdf()!
    success = pdf.loadFile(filePath: "qa_data/pdf/invoice_template.pdf")
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    //  Values for every placeholder except {{po}} (the purchase order number, which this customer has none of).
    let json = CkoJsonObject()!
    json.updateString(jsonPath: "placeholders.customer", value: "Acme Corp")
    json.updateString(jsonPath: "placeholders.date", value: "2026-10-18")
    json.updateString(jsonPath: "placeholders.qty1", value: "2")
    json.updateString(jsonPath: "placeholders.desc1", value: "Cordless drill, 18 V")
    json.updateString(jsonPath: "placeholders.price1", value: "$460.00")
    json.updateString(jsonPath: "placeholders.amount1", value: "$920.00")
    json.updateString(jsonPath: "placeholders.qty2", value: "6")
    json.updateString(jsonPath: "placeholders.desc2", value: "Galvanized hinge, 4 inch")
    json.updateString(jsonPath: "placeholders.price2", value: "$12.50")
    json.updateString(jsonPath: "placeholders.amount2", value: "$75.00")
    json.updateString(jsonPath: "placeholders.subtotal", value: "$995.00")
    json.updateString(jsonPath: "placeholders.taxRate", value: "7.35%")
    json.updateString(jsonPath: "placeholders.tax", value: "$73.13")
    json.updateString(jsonPath: "placeholders.total", value: "$1,068.13")

    let jsonOut = CkoJsonObject()!

    //  The default, "error": the unfilled {{po}} is a problem and nothing would be applied.
    success = pdf.textReplace(op: "check", jsonIn: json, jsonOut: jsonOut)
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    print("error (default): ok = \(jsonOut.bool(of: "ok")), problem: \(jsonOut.string(of: "problems[0].field")!) \(jsonOut.string(of: "problems[0].reason")!)")

    //  "keep": {{po}} stays on the page, literally.
    json.updateString(jsonPath: "unusedPlaceholders", value: "keep")
    success = pdf.textReplace(op: "check", jsonIn: json, jsonOut: jsonOut)
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    print("keep: ok = \(jsonOut.bool(of: "ok"))")

    //  "blank": {{po}} is replaced by nothing, leaving "PO Number:" with an empty value.
    json.updateString(jsonPath: "unusedPlaceholders", value: "blank")
    success = pdf.textReplace(op: "apply", jsonIn: json, jsonOut: jsonOut)
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    print("blank: applied = \(jsonOut.bool(of: "applied"))")

    success = pdf.writeFile(path: "qa_output/invoice_no_po.pdf")
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    //  Sample output:

    //  error (default): ok = false, problem: po unusedPlaceholder
    //  keep: ok = true
    //  blank: applied = true

}