Zig

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.

Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    const pdf = try chilkat.Pdf.init();
    defer pdf.deinit();

    // Load a PDF to be signed.
    // The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
    pdf.loadFile("qa_data/pdf/hello.pdf") catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    // Options for signing are specified in JSON.
    const json = try chilkat.JsonObject.init();
    defer json.deinit();

    // In most cases, the signingCertificateV2 and signingTime attributes are required.
    json.updateInt("signingCertificateV2", 1) catch {};
    json.updateInt("signingTime", 1) catch {};

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

    // 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", "green-check-grey-circle") catch {};

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

    // 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", "100") catch {};

    // 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.)
    const cert = try chilkat.Cert.init();
    defer cert.deinit();
    cert.loadPfxFile("qa_data/pfx/myPdfSigningCert.pfx", "secret") catch {
        std.debug.print("{s}\n", .{try cert.getLastErrorText(alloc)});
        return;
    };

    // Tell the pdf object to use the certificate for signing.
    pdf.setSigningCert(cert) catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    pdf.signPdf(json, "qa_output/hello_signed.pdf") catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("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"
    json.updateString("appearance.image", "green-check-green-circle") catch {};
    // 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)
}