Yeah, I'm really hoping to not require us to run an entire browser or depend on an external service to generate PDFs. The approaches I found in my research were:

When I apt-get install wkhtmltopdf (or something like that) on aux001, which is Ubuntu 14, I get this:

Just some observations after popping open PDF invoices which have shown up in my inbox recently:

See PHI1367, which featured a specific case where git repack unambiguously did something good instead of being magic fairy dust that we sprinkle around to ward off demons.

This is also more "while I'm here", but there's no web UI way to void an invoice right now. It would be nice to have a "Void Invoice" button for staff instead of requiring database fiddling, since this comes up occasionally.

Per T13366, I'm just going to get rid of this behavior for now, with the expectation that we'll soon begin generating side-channel emails for "Billing Department Email Address" under the umbrella of T8389 and could put "Merchant Emails" on a similar channel if we want.

See also https://phabricator.wikimedia.org/T197935.

$info_object = new PhabricatorPDFInfoObject();

PDF files appear to consist of a series of objects that (mostly) look like this:

See T13357 for followup.

This is likely straightforward.

See also PHI1358, which is an actual concrete request for sensible relabeling of "Description" in a subtype.