C

PDF Signatures with Built-in SVG Graphics

See more PDF Signatures Examples

This example demonstrates the built-in SVG graphics that can be applied to the appearance when signing a PDF.

Note: This example requires Chilkat v9.5.0.85 or greater.

C

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

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

    success = FALSE;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    pdf = CkPdf_Create();

    // Load a PDF to be signed.
    // The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
    success = CkPdf_LoadFile(pdf,"qa_data/pdf/hello.pdf");
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        return;
    }

    // Options for signing are specified in JSON.
    json = CkJsonObject_Create();

    // In most cases, the signingCertificateV2 and signingTime attributes are required.
    CkJsonObject_UpdateInt(json,"signingCertificateV2",1);
    CkJsonObject_UpdateInt(json,"signingTime",1);

    // Specify the location/position, scale, and content of the signature's appearance.
    CkJsonObject_UpdateInt(json,"page",1);
    CkJsonObject_UpdateString(json,"appearance.y","top");
    CkJsonObject_UpdateString(json,"appearance.x","left");
    CkJsonObject_UpdateString(json,"appearance.fontScale","10.0");
    CkJsonObject_UpdateString(json,"appearance.text[0]","Digitally signed by: cert_cn");
    CkJsonObject_UpdateString(json,"appearance.text[1]","current_dt");
    CkJsonObject_UpdateString(json,"appearance.text[2]","The crazy brown fox jumps over the lazy dog.");

    // In addition to the above, this example adds a built-in SVG graphic to the appearance.
    // The built-in SVG graphic is specified by a name, such as "green-check-grey-circle".
    // The full list of graphic names and images are shown below.
    CkJsonObject_UpdateString(json,"appearance.image","green-check-grey-circle");

    // The graphic can be placed "left", "center", or "right".
    // If "center", then the graphic is displayed behind the text.
    CkJsonObject_UpdateString(json,"appearance.imagePlacement","left");

    // The graphic's opacity can range from 1 to 100.
    // Centered graphics look best with less opacity (50 or less).
    // In this example, we'll keep the opacity at 100.
    CkJsonObject_UpdateString(json,"appearance.imageOpacity","100");

    // Here's an example of the signature's appearance if we centered the SVG graphic with an opacity of 40%
    // (image:https://example-code.com/images/centered_svg.jpg/endImage)

    // Load the signing certificate. (Use your own certificate.)
    cert = CkCert_Create();
    success = CkCert_LoadPfxFile(cert,"qa_data/pfx/myPdfSigningCert.pfx","secret");
    if (success == FALSE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkCert_Dispose(cert);
        return;
    }

    // Tell the pdf object to use the certificate for signing.
    success = CkPdf_SetSigningCert(pdf,cert);
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkCert_Dispose(cert);
        return;
    }

    success = CkPdf_SignPdf(pdf,json,"qa_output/hello_signed.pdf");
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkCert_Dispose(cert);
        return;
    }

    printf("The PDF has been successfully cryptographically signed.\n");

    // The appearance of the signature appears in Adobe Acrobat as shown here:

    // (image:https://example-code.com/images/pdf_signature_green_check_grey_circle.jpg/endImage)

    // The SVG icon graphics are embedded within the Chilkat library, 
    // and were graciously provided by uxwing - Free SVG Icons 
    // 
    // The uxwing licensing terms are reproduced here and can be verified at uxwing licensing

    // Icons from uxwing.com are free (see https://uxwing.com/license/)
    // 	- All icons on UXWing free to download, and use personal, commercial projects.
    // 	- Attribution and Credit is NOT required, however, any credit will be much appreciated.
    // 	- There is no limit to the number of times you can use.
    // 	- You may modify the resources according to your requirements.

    // The set of SVG names and the corresponding graphics are shown below.
    // 
    // For example, if we specify "green-check-green-circle"
    CkJsonObject_UpdateString(json,"appearance.image","green-check-green-circle");
    // We get:
    // (image:https://example-code.com/images/green-check-green-circle.jpg/endImage)

    // "application-approved"
    // (image:https://example-code.com/images/application-approved.jpg/endImage)

    // "application-rejected"
    // (image:https://example-code.com/images/application-rejected.jpg/endImage)

    // "document-accepted"
    // (image:https://example-code.com/images/document-accepted.jpg/endImage)

    // "approved"
    // (image:https://example-code.com/images/approved.jpg/endImage)

    // "blue-check-mark"
    // (image:https://example-code.com/images/blue-check-mark.jpg/endImage)

    // "green-check-mark"
    // (image:https://example-code.com/images/green-check-mark.jpg/endImage)

    // "green-check-grey-circle"
    // (image:https://example-code.com/images/green-check-grey-circle.jpg/endImage)

    // "red-x-red-circle"
    // (image:https://example-code.com/images/red-x-red-circle.jpg/endImage)

    // "rejected"
    // (image:https://example-code.com/images/rejected.jpg/endImage)

    // "result-failure"
    // (image:https://example-code.com/images/result-failure.jpg/endImage)

    // "result-pass"
    // (image:https://example-code.com/images/result-pass.jpg/endImage)

    // "signature"
    // (image:https://example-code.com/images/signature.jpg/endImage)

    // "document-check"
    // (image:https://example-code.com/images/document-check.jpg/endImage)

    // "document-x"
    // (image:https://example-code.com/images/document-x.jpg/endImage)

    // "red-x-grey-circle"
    // (image:https://example-code.com/images/red-x-grey-circle.jpg/endImage)


    CkPdf_Dispose(pdf);
    CkJsonObject_Dispose(json);
    CkCert_Dispose(cert);

    }