Objective-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.

Objective-C

#import <CkoPdf.h>
#import <CkoJsonObject.h>
#import <CkoCert.h>

BOOL success = NO;

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

CkoPdf *pdf = [[CkoPdf alloc] init];

//  Load a PDF to be signed.
//  The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
success = [pdf LoadFile: @"qa_data/pdf/hello.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

//  Options for signing are specified in JSON.
CkoJsonObject *json = [[CkoJsonObject alloc] init];

//  In most cases, the signingCertificateV2 and signingTime attributes are required.
[json UpdateInt: @"signingCertificateV2" value: [NSNumber numberWithInt: 1]];
[json UpdateInt: @"signingTime" value: [NSNumber numberWithInt: 1]];

//  Specify the location/position, scale, and content of the signature's appearance.
[json UpdateInt: @"page" value: [NSNumber numberWithInt: 1]];
[json UpdateString: @"appearance.y" value: @"top"];
[json UpdateString: @"appearance.x" value: @"left"];
[json UpdateString: @"appearance.fontScale" value: @"10.0"];
[json UpdateString: @"appearance.text[0]" value: @"Digitally signed by: cert_cn"];
[json UpdateString: @"appearance.text[1]" value: @"current_dt"];
[json UpdateString: @"appearance.text[2]" value: @"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.
[json UpdateString: @"appearance.image" value: @"green-check-grey-circle"];

//  The graphic can be placed "left", "center", or "right".
//  If "center", then the graphic is displayed behind the text.
[json UpdateString: @"appearance.imagePlacement" value: @"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.
[json UpdateString: @"appearance.imageOpacity" value: @"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.)
CkoCert *cert = [[CkoCert alloc] init];
success = [cert LoadPfxFile: @"qa_data/pfx/myPdfSigningCert.pfx" password: @"secret"];
if (success == NO) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

//  Tell the pdf object to use the certificate for signing.
success = [pdf SetSigningCert: cert];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

success = [pdf SignPdf: json outFilePath: @"qa_output/hello_signed.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

NSLog(@"%@",@"The PDF has been successfully cryptographically signed.");

//  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"
[json UpdateString: @"appearance.image" value: @"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)