Swift Requires Chilkat v11.7.0+

Add an Image (Logo) Watermark to a PDF

See more PDF Watermark Examples

Demonstrates an image watermark placed in a corner of every page. The image is a PNG or JPEG given either by path ("image.path") or, as here, as base64 in the JSON itself ("image.base64"), which suits a server that keeps its logo in a database rather than on disk. PNG transparency is kept. Giving only a width keeps the aspect ratio, and the units member says those numbers are inches rather than points. 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 four_pages.pdf

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

    let json = CkoJsonObject()!
    json.updateString(jsonPath: "type", value: "image")

    //  A small PNG logo, base64 encoded.  Use "image.path" instead to name a PNG or JPEG file:
    //     ignore = json.UpdateString("image.path","logo.png");
    json.updateString(jsonPath: "image.base64", value: "iVBORw0KGgoAAAANSUhEUgAAAGAAAAAgCAYAAADtwH1UAAAApElEQVR42u3a7QmAIBgAYTdpo/ZphhZti6IBylLrlXoO/G3cIeFHSgAAFDKM08rCy8Jzg6Ug8UJ0JF+EDuSXRGgxX8+jufxlTk0nFuCCiF360aidXICMiDP5uQgCXAxQI782ggAHEu7IP4sgQOcBIMA35ItgBQhQEqBmtbX6xl//hAUI3gcIELwTFiD4LEiA4NNQAYLvA+BGzJ0wvIrwLggA8DgbwPbrr8c7+lkAAAAASUVORK5CYII=")

    //  The size to draw it at.  Give only the width and the height follows the aspect ratio.
    json.updateString(jsonPath: "units", value: "in")
    json.updateNumber(jsonPath: "image.width", numericStr: "1.5")

    //  Bottom-right, half an inch in from the page edges.
    json.updateString(jsonPath: "position.align", value: "bottomRight")
    json.updateNumber(jsonPath: "position.margin", numericStr: "0.5")
    json.updateNumber(jsonPath: "opacity", numericStr: "0.85")
    json.updateString(jsonPath: "id", value: "logo")

    let jsonOut = CkoJsonObject()!
    success = pdf.watermark(op: "add", jsonIn: json, jsonOut: jsonOut)
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    print("id: \(jsonOut.string(of: "id")!) pages: \(jsonOut.string(of: "pages")!)")

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

    //  Sample output:

    //  id: logo pages: 1-4

}