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VB.NET

PDF Signatures with Built-in SVG Graphics

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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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VB.NET 
Dim success As Boolean = False

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

Dim pdf As New Chilkat.Pdf

' 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 = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


' Options for signing are specified in JSON.
Dim json As New Chilkat.JsonObject

' In most cases, the signingCertificateV2 and signingTime attributes are required.
json.UpdateInt("signingCertificateV2",1)
json.UpdateInt("signingTime",1)

' Specify the location/position, scale, and content of the signature's appearance.
json.UpdateInt("page",1)
json.UpdateString("appearance.y","top")
json.UpdateString("appearance.x","left")
json.UpdateString("appearance.fontScale","10.0")
json.UpdateString("appearance.text[0]","Digitally signed by: cert_cn")
json.UpdateString("appearance.text[1]","current_dt")
json.UpdateString("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.
json.UpdateString("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.
json.UpdateString("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.
json.UpdateString("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.)
Dim cert As New Chilkat.Cert
success = cert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","secret")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


' Tell the pdf object to use the certificate for signing.
success = pdf.SetSigningCert(cert)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


success = pdf.SignPdf(json,"qa_output/hello_signed.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("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","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)