Christmas terminal

xmasterm.py

#!/usr/bin/python3
# Xmas Terminal
# Copyright (C) 2012, 2015  Yu-Jie Lin
#
# Modified from urwid's code by Yu-Jie Lin
#
# Blog: http://blog.yjl.im/2012/12/christmas-terminal.html
# Gist: https://gist.github.com/livibetter/127287ca94164e38cb09
# Video: https://www.youtube.com/watch?v=jiBcaV0FqTg
#
# Urwid terminal emulation widget
#    Copyright (C) 2010  aszlig
#    Copyright (C) 2011  Ian Ward
# Urwid terminal emulation widget example app
#    Copyright (C) 2010  aszlig
#
#    This library is free software; you can redistribute it and/or
#    modify it under the terms of the GNU Lesser General Public
#    License as published by the Free Software Foundation; either
#    version 2.1 of the License, or (at your option) any later version.
#
#    This library is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#    Lesser General Public License for more details.
#
#    You should have received a copy of the GNU Lesser General Public
#    License along with this library; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# Urwid web site: http://excess.org/urwid/

import sys
import time
from functools import reduce
from itertools import cycle
from random import randint

import urwid
import urwid.vterm
from urwid import AttrSpec

if sys.version_info.major == 2:
  from itertools import imap
elif sys.version_info.major >= 3:
  imap = map


recolor = lambda l, c: (c, ) + l[1:]

snow = []
MAX_SNOW = 20

r = AttrSpec('light red', 'default', 16)
b = AttrSpec('light blue', 'default', 16)
g = AttrSpec('light green', 'default', 16)
y = AttrSpec('yellow', 'default', 16)
w = AttrSpec('white', 'default', 16)
snow_text = (w, None, b'*')
c = (r, b, g, y) * 2
n = len(c) // 2
color_seq = tuple(
  reduce(tuple.__add__, ((x, ) * 2 for x in c[i:i + n]))
  for i in range(n)
)


def fall(w, h):

    global snow
    if len(snow) < MAX_SNOW and not randint(0, 3):
        snow.append([randint(0, w - 1), -1])

    for s in snow:
        if randint(0, 9):
            s[1] += 1

    f = lambda s: s[1] < h and w > s[0] >= 0
    # remove snow
    snow = list(filter(f, snow))


def content(self, trim_left=0, trim_right=0, cols=None, rows=None,
            attr_map=None):
    _row = 0
    n = len(color_seq)
    offset = int(time.time() % n)

    if self.scrolling_up == 0:
        for line in self.term:
            i = _row + offset
            newline = list(imap(recolor, line, cycle(color_seq[i % n])))
            for s in (s for s in snow if s[1] == _row):
                newline[s[0]] = snow_text
            yield newline
            _row += 1
    else:
        buf = self.scrollback_buffer + self.term
        for line in buf[-(self.height + self.scrolling_up):-self.scrolling_up]:
            yield line


urwid.vterm.TermCanvas.content = content


def update_timer(loop, term):

    loop.draw_screen()
    loop.set_alarm_in(0.5, update_timer, term)
    fall(term.width, term.height)


def main():

    term = urwid.Terminal(None)

    def quit(*args, **kwargs):
        raise urwid.ExitMainLoop()

    urwid.connect_signal(term, 'closed', quit)

    loop = urwid.MainLoop(term, handle_mouse=False)

    term.main_loop = loop
    loop.set_alarm_in(1, update_timer, term)
    loop.run()

if __name__ == '__main__':
    main()