Only one text field, and inside it - different sections, menus, and popups, all in ascii. How to make that?

I mean something like this:

╔═════════════════╦══════╗
║                 ║      ║
║                 ║      ║
║                 ║      ║
║                 ║      ║
╚═════════════════╩══════╝

I see only the possibility to draw each line, calculating line length and somewhat manually. But maybe there is some kind of a simple way i am not aware of?