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Digitally signing PDF with DynaPDF and custom signature appearance

For some time now we can sign PDFs with DynaPDF functions automatically in a script in FileMaker. For next pre-release we add a new feature to add a custom signature appearance. You define in your script how the PDF draws the signature on the page and includes the validation icon. That validation icon is a special feature of the PDF reader where they draw a checkmark to let you know the signature is valid. Like this screenshot:

We draw in the box there to show it's signed, write the name there and then tell the PDF viewer to place the icon left to the text. If the PDF viewer doesn't know or doesn't check, this should display a question mark. See picture on the right.

To do this, you do three steps:
  1. You call DynaPDF.CreateSigField to create a signature field on the PDF and specify the coordinates. You choose where to put it on the page and yes, you can render various areas and look for white space.
  2. To place the validation icon, please use our new DynaPDF.PlaceSigFieldValidateIcon function. This receives relative coordinates within the signature field rectangle.
  3. Then use DynaPDF.CreateSigFieldAP to create a custom signature field appearance stream and draw some text into it. You draw what you like within the given rectangle of your signature and the icon is later placed on top over the custom drawing. Please call DynaPDF.EndTemplate when done with the drawing.
Now you save the PDF and use our DynaPDF.SaveAndSignFile function to provide the file path to the private key file and let the plugin close the file with valid signature.

PS: Also available for Xojo with DynaPDFMBS class, see signature appearance project. FileMaker Plugin
22 04 20 - 12:00

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