(Tcl) 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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load ./chilkat.dll

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

set pdf [new_CkPdf]

# Load a PDF to be signed.
# The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
set success [CkPdf_LoadFile $pdf "qa_data/pdf/hello.pdf"]
if {$success == 0} then {
    puts [CkPdf_lastErrorText $pdf]
    delete_CkPdf $pdf
    exit
}

# Options for signing are specified in JSON.
set json [new_CkJsonObject]

# 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%


# Load the signing certificate. (Use your own certificate.)
set cert [new_CkCert]

set success [CkCert_LoadPfxFile $cert "qa_data/pfx/myPdfSigningCert.pfx" "secret"]
if {$success == 0} then {
    puts [CkCert_lastErrorText $cert]
    delete_CkPdf $pdf
    delete_CkJsonObject $json
    delete_CkCert $cert
    exit
}

# Tell the pdf object to use the certificate for signing.
set success [CkPdf_SetSigningCert $pdf $cert]
if {$success == 0} then {
    puts [CkPdf_lastErrorText $pdf]
    delete_CkPdf $pdf
    delete_CkJsonObject $json
    delete_CkCert $cert
    exit
}

set success [CkPdf_SignPdf $pdf $json "qa_output/hello_signed.pdf"]
if {$success == 0} then {
    puts [CkPdf_lastErrorText $pdf]
    delete_CkPdf $pdf
    delete_CkJsonObject $json
    delete_CkCert $cert
    exit
}

puts "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"
CkJsonObject_UpdateString $json "appearance.image" "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"


delete_CkPdf $pdf
delete_CkJsonObject $json
delete_CkCert $cert