Remove digital signatures

flattensignature

##GITHUB:https://github.com/itext/i7js-examples/blob/develop/src/main/java/com/itextpdf/samples/sandbox/acroforms/FlattenSignature.java##

##GITHUB:https://github.com/itext/i7ns-samples/blob/develop/itext/itext.samples/itext/samples/sandbox/acroforms/FlattenSignature.cs##

Resources

https://github.com/itext/i7js-examples/blob/develop/src/main/resources/pdfs/input_signed.pdf

Results

https://github.com/itext/i7js-examples/blob/develop/cmpfiles/sandbox/acroforms/cmp_flatten_signature.pdf