C 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. C

#include <C_CkPdf.h>
#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPdf pdf;
    HCkJsonObject json;
    HCkJsonObject jsonOut;

    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 = CkPdf_Create();
    success = CkPdf_LoadFile(pdf,"qa_data/pdf/four_pages.pdf");
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        return;
    }

    json = CkJsonObject_Create();
    CkJsonObject_UpdateString(json,"type","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");
    CkJsonObject_UpdateString(json,"image.base64","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.
    CkJsonObject_UpdateString(json,"units","in");
    CkJsonObject_UpdateNumber(json,"image.width","1.5");

    //  Bottom-right, half an inch in from the page edges.
    CkJsonObject_UpdateString(json,"position.align","bottomRight");
    CkJsonObject_UpdateNumber(json,"position.margin","0.5");
    CkJsonObject_UpdateNumber(json,"opacity","0.85");
    CkJsonObject_UpdateString(json,"id","logo");

    jsonOut = CkJsonObject_Create();
    success = CkPdf_Watermark(pdf,"add",json,jsonOut);
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    printf("id: %s pages: %s\n",CkJsonObject_stringOf(jsonOut,"id"),CkJsonObject_stringOf(jsonOut,"pages"));

    success = CkPdf_WriteFile(pdf,"qa_output/four_pages_logo.pdf");
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    //  Sample output:

    //  id: logo pages: 1-4


    CkPdf_Dispose(pdf);
    CkJsonObject_Dispose(json);
    CkJsonObject_Dispose(jsonOut);

    }