How to get the first visible line in a TRichEdit

Problem/Question/Abstract:

How can I get the number of the first line that is shown in a TRichEdit when it has been scrolled down?

Answer:

Take a look at source of messages.pas unit and search for "EM_" to see a list of related messages.

RichEdit1.Perform(EM_GETFIRSTVISIBLELINE, 0, 0)