I have a fundamental-mode buffer with italics set. When I copy the buffer and paste it to an email compose buffer, the text appears but the italics don't. But if I open a .odt file with some italics in another application, copy its text, and paste it to the email compose buffer, the text appears, with italics. If there is a command that lets me promote my buffer to some other mode, so that when I copy/paste it elsewhere, the italics come along? I don't want to use my fingers for anything. I have hooks that, on read-in, read a file and clear the high bits it finds, but set the italic face property on those characters. Ideal would be a command that said write-out-this-buffer-and-make-a-.odt-file-out-of-it. If promotion to some other mode would have the effect I need, how could I cause that?
How can I copy text with face properties from an Emacs buffer, so that when I paste it to another application, the face properties appear?
I'm not sure this fix your particular problem, but the package highlight2clipboard allows you to copy highlighted text from an Emacs buffer to an external application.
yank-handled-propertiesto make sure that gets transferred when you yank text. But who knows what the text you copy from some other application actually contains as characters information? Does it include chars with fonts, using different a different font for italics, for instance? How does it represent that copied info?