blessed

A curses-like library for node.js.

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FAQ

  1. Why doesn’t the Linux console render lines correctly on Ubuntu?
    • You need to install the ncurses-base package and the ncurses-term package. (#98)
  2. Why do vertical lines look chopped up in iTerm2?
    • All ACS vertical lines look this way in iTerm2 with the default font.
  3. Why can’t I use my mouse in Terminal.app?
    • Terminal.app does not support mouse events.
  4. Why doesn’t the OverlayImage element appear in my terminal?
    • The OverlayImage element uses w3m to display images. This generally only works on X11+xterm/urxvt, but it may work on other unix terminals.
  5. Why can’t my mouse clicks register beyond 255 cells?
    • Older versions of VTE do not support any modern mouse protocol. On top of that, the old X10 protocol it does implement is bugged. Through several workarounds we’ve managed to get the cell limit from 127 to 255. If you’re not happy with this, you may want to look into using xterm or urxvt, or a terminal which uses a modern VTE, like gnome-terminal.
  6. Is blessed efficient?
    • Yes. Blessed implements CSR and uses the painter’s algorithm to render the screen. It maintains two screen buffers so it only needs to render what has changed on the terminal screen.
  7. Will blessed work with all terminals?
    • Yes. Blessed has a terminfo/termcap parser and compiler that was written from scratch. It should work with every terminal as long as a terminfo file is provided. If you notice any compatibility issues in your termial, do not hesitate to post an issue.
  8. What is “curses” and “ncurses”?
    • [“curses”][curses] was an old library written in the early days of unix which allowed a programmer to easily manipulate the cursor in order to render the screen. [“ncurses”][ncurses] is a free reimplementation of curses. It improved upon it quite a bit by focusing more on terminal compatibility and is now the standard library for implementing terminal programs. Blessed uses neither of these, and instead handles terminal compatibility itself.
  9. What is the difference between blessed and blessed-contrib?
    • blessed is a major piece of code which reimplements curses from the ground up. A UI API is then layered on top of this. [blessed-contrib][contrib] is a popular library built on top of blessed which makes clever use of modules to implement useful widgets like graphs, ascii art, and so on.
  10. Are there blessed-like solutions for non-javascript platforms?
    • Yes. There are some fantastic solutions out there.
    • Perl: [Curses::UI][curses-ui]
    • Python: [Urwid][urwid]
    • Go: [termui][termui] & [termbox-go][termbox]