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Introduction

Blessed is an easy, practical library for making terminal apps, by providing an elegant, well-documented interface to Colors_, Keyboard_ input, and screen position and Location_ capabilities.

from blessed import Terminal

term = Terminal()

print(term.home + term.clear + term.move_y(term.height // 2))
print(term.black_on_darkkhaki(term.center('press any key to continue.')))

with term.cbreak(), term.hidden_cursor():
    inp = term.inkey()

print(term.move_down(2) + 'You pressed ' + term.bold(repr(inp)))

:alt: Animation of running the code example

It's meant to be fun and easy, to do basic terminal graphics and styling with Python using blessed. Terminal_ is the only class you need to import and the only object you should need for Terminal capabilities.

Whether you want to improve CLI apps with colors, or make fullscreen applications or games, blessed should help get you started quickly. Your users will love it because it works on Windows, Mac, and Linux, and you will love it because it has plenty of documentation and examples!

Full documentation at https://blessed.readthedocs.io/en/latest/

Examples

:alt: animations of x11-colorpicker.py, bounce.py, worms.py, and plasma.py x11-colorpicker.py_, bounce.py_, worms.py_, and plasma.py_ demonstration programs from our repository.

:alt: colored and dimensional cellular automata in scrolling animation cellestial.py_ demonstration program from our repository.

Exemplary 3rd-party examples which use blessed,

:alt: Screenshot of 'Voltron' (By the author of Voltron, from their README). Voltron_ is an extensible debugger UI toolkit written in Python

:alt: Animation of 'cursewords' (By the author of cursewords, from their README). cursewords_ is "graphical" command line program for solving crossword puzzles in the terminal.

:alt: Animations from 'Dashing' (By the author of Dashing, from their README) Dashing_ is a library to quickly create terminal-based dashboards.

:alt: Animations from 'Enlighten' (By the author of Enlighten, from their README) Enlighten_ is a console progress bar library that allows simultaneous output without redirection.

Requirements

Blessed works with Windows, Mac, Linux, and BSD's, on Python 3.7+.

Brief Overview

Blessed is more than just a Python wrapper around curses_:

• Styles_, Colors_, and maybe a little positioning without necessarily clearing the whole screen

first.

• Works great with Python's new f-strings_ or any other kind of string formatting.
• Provides up-to-the-moment Location_ and terminal height and width, so you can respond to terminal

size changes.

• Avoids making a mess if the output gets piped to a non-terminal, you can output sequences to any

file-like object such as StringIO, files, pipes or sockets.

• Uses terminfo(5)_ so it works with any terminal type and capability: No more C-like calls to

tigetstr_ and tparm_.

• Non-obtrusive calls to only the capabilities database ensures that you are free to mix and match

with calls to any other curses application code or library you like.

• Provides context managers Terminal.fullscreen()_ and Terminal.hidden_cursor()_ to safely

express terminal modes, curses development will no longer fudge up your shell.

• Act intelligently when somebody redirects your output to a file, omitting all of the special

sequences colors, but still containing all of the text.

Blessed is a fork of blessings, which does all of the same above with the same API, as well as following enhancements:

• Windows support, new since Dec. 2019!
• Dead-simple keyboard handling: safely decoding unicode input in your system's preferred locale and

supports application/arrow keys.

• 24-bit color support, using Terminal.color_rgb()_ and Terminal.on_color_rgb()_ and all X11

Colors_ by name, and not by number.

• Determine cursor location using Terminal.get_location()_, enter key-at-a-time input mode using

Terminal.cbreak()_ or Terminal.raw()_ context managers, and read timed key presses using Terminal.inkey()_.

• Allows the printable length of strings that contain sequences to be determined by

Terminal.length()_, supporting additional methods Terminal.wrap()_ and Terminal.center()_, terminal-aware variants of the built-in function textwrap.wrap()_ and method str.center()_, respectively.

• Allows sequences to be removed from strings that contain them, using Terminal.strip_seqs()_ or

sequences and whitespace using Terminal.strip()_.

• Per-character text sizing using the kitty text sizing protocol_, via Terminal.text_sized()_

and Terminal.does_text_sizing()_.

Before And After

With the built-in curses_ module, this is how you would typically print some underlined text at the bottom of the screen:

from curses import tigetstr, setupterm, tparm
from fcntl import ioctl
from os import isatty
import struct
import sys
from termios import TIOCGWINSZ

# If we want to tolerate having our output piped to other commands or
# files without crashing, we need to do all this branching:
if hasattr(sys.stdout, 'fileno') and isatty(sys.stdout.fileno()):
    setupterm()
    sc = tigetstr('sc')
    cup = tigetstr('cup')
    rc = tigetstr('rc')
    underline = tigetstr('smul')
    normal = tigetstr('sgr0')
else:
    sc = cup = rc = underline = normal = ''

# Save cursor position.
print(sc)

if cup:
    # tigetnum('lines') doesn't always update promptly, hence this:
    height = struct.unpack('hhhh', ioctl(0, TIOCGWINSZ, '\000' * 8))[0]

    # Move cursor to bottom.
    print(tparm(cup, height - 1, 0))

print(f'This is {underline}underlined{normal}!')

# Restore cursor position.
print(rc)

The same program with Blessed is simply:

from blessed import Terminal

term = Terminal()
with term.location(0, term.height - 1):
    print('This is ' + term.underline('underlined') + '!', end='')