GNOME Bugzilla – Bug 759203
Add vector or raster digital signature
Last modified: 2018-05-22 16:25:47 UTC
Some forms require a hand signature on them. Adobe Reader has a feature to stamp such a signature. Note that this is not the same as a digital embedded signature (e.g. PKI). Example: http://www.howtogeek.com/215485/sign-pdf-documents-without-printing-and-scanning-them-from-any-device/ Without this, the user must print, sign, and scan or manually export the page to be signed, import into something like GIMP, sign the de-vectorized / rasterized version, re-import back into the document via pdftk or some such, and then save.
For that, we need to get support of freehand (ink) annotation in poppler. So far, you can do it with xournal (without the dancing of printing/scanning). That is, if you have a tablet (either external or integrated).
Yes, that would make sense. Although I think the way Adobe does it is not as an "ink" annotation, but as a vectorized string of the user's name. Still though, I think freehand ink annotation would be the best way. I wonder what the status of that is with poppler?
By looking at the screenshots only, I believe that Adobe stores the signatures as PDF snippets or something alike. It is not implemented in poppler (poppler-glib to be precise), but it should not be hard to do that. At least not the get the basic working. It would be a matter of looking how the other annotations are implemented (highlight and shape). However, I wonder that once having the ink annotation working, would storing the signature make sense? It seems to me that it would be a matter of convenience... only if the user have to sign many documents in a row. Otherwise, having the annotation in place would be enough.
I think it would make more sense to store just the ink vector annotation than having a separate signature. I wonder if there is an upstream request with poppler? I wouldn't know what they'd call such a thing.
I thought where was a bug filed for that, but I could not find it.
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