Digital signatures not able to be verified by Adobe after adding the signature image

[SergenN]

Currently there is an issue with this package that does not allow the signatures to be verified in Adobe after the image objects have been inserted into the document.

In the code after the graphics are inserted into the document the graphics state is restored:

content.operations.push(Operation::new("Q", vec![]));

Commenting out this line will result in a valid signed document with signature images embedded in the document. What is the purpose of this line and is it fine if we remove this?

[ralpha]

The line:

pdf_signing/src/image_insert.rs

Lines 79 to 80 in c1f7fb2

	// `Q` = Restore graphics state
	content.operations.push(Operation::new("Q", vec![]));

Is the opposite of:

pdf_signing/src/image_insert.rs

Lines 60 to 61 in c1f7fb2

	// `q` = Save graphics state
	content.operations.push(Operation::new("q", vec![]));

One saves the graphics state the other restores it.
This means that the matrix transformations does not apply to all other graphic states in the document.

We where aware of this issue and tried to resolve it though https://stackoverflow.com/questions/72935931/pdf-signature-expected-a-dict-object
But this has yet to be tested and fixed.