(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.

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

// 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
BOOL 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%


// 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:



// 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:


// "application-approved"


// "application-rejected"


// "document-accepted"


// "approved"


// "blue-check-mark"


// "green-check-mark"


// "green-check-grey-circle"


// "red-x-red-circle"


// "rejected"


// "result-failure"


// "result-pass"


// "signature"


// "document-check"


// "document-x"


// "red-x-grey-circle"