Is there a tool already to draw flow charts and diagram strictly for terminals?

I want to draw stuff either on ema开发者_StackOverflow中文版cs or vim, or even in the Terminal directly via a specific tool. Basic saving capabilities, as text obviously or rendered as an image. I've used asciiflow.com on the web, and it does most of the job but I'm surprised there isn't a tool for monospace font editors, in an off-line environment for linux/osx. Does anyone know of such tool? If it doesn't exist, I'll roll up my sleeve, spit in my hands and attempt it in elisp.

As described in http://emacs-fu.blogspot.com/2009/01/drawing-pictures.html you can use Emacs picture-mode to draw diagrams. Then you can use ditaa to convert the text to images (which can be run from within Emacs as the described in the blog post).