Responsive terminal layout bootstrap

#! /usr/bin/env python
import sys
import signal
import os
import fcntl
import termios
import struct

block = os.O_NONBLOCK if 'O_NONBLOCK' in dir(os) else (
    os.NOBLOCK if 'NONBLOCK' in dir(os) else None)

r = sys.stdin.fileno()
w = sys.stdout.fileno()

r_flags = fcntl.fcntl(r, fcntl.F_GETFL)

if r_flags & block:
    fcntl.fcntl(r, fcntl.F_SETFL, r_flags & ~block)
w_flags = fcntl.fcntl(w, fcntl.F_GETFL)
if w_flags & block:
    fcntl.fcntl(w, fcntl.F_SETFL, w_flags & ~block)


def main():
    def resize(*args):
        h, w, hp, wp = struct.unpack('HHHH', fcntl.ioctl(0, termios.TIOCGWINSZ, struct.pack('HHHH', 0, 0, 0, 0)))  # noqa
        while 1:
            try:
                # render just a simple bordered box with resolution in middle
                x = '{0} x {1}'.format(w, h)

                l = int(float(w) / 2)
                t = int(float(h) / 2)
                fill = (w - l - (len(x) - int(len(x) / 2)) - 1)

                screen = '.' + '.' * (w - 2) + '.\n' + \
                    (':' + ' ' * (w - 2) + ':\n') * (t - 1) + \
                    (':' + ' ' * (l - int(len(x) / 2) - 1) + x +
                     ' ' * fill + ':\n') + \
                    (':' + ' ' * (w - 2) + ':\n') * (h - t - 2) + \
                    (':' + '.' * (w - 2) + ':')

                sys.stdout.write(screen)
                break
            except:
                continue

    signal.signal(signal.SIGWINCH, resize)

    try:
        sys.stdout.write('\033[?1049h\033[H')
        resize()
        r_old = termios.tcgetattr(r)
        r_new = termios.tcgetattr(r)
        r_new[3] = r_new[3] & ~termios.ICANON & ~termios.ECHO
        termios.tcsetattr(r, termios.TCSANOW, r_new)

        try:
            while 1:
                try:
                    c = sys.stdin.read(1)
                    if c == '\n':
                        break
                except IOError:
                    pass
        finally:
            termios.tcsetattr(r, termios.TCSAFLUSH, r_old)
    except KeyboardInterrupt:
        pass
    finally:
        fcntl.fcntl(r, fcntl.F_SETFL, r_flags)
        fcntl.fcntl(w, fcntl.F_SETFL, w_flags)
        sys.stdout.write('\033[?1049l')

if __name__ == '__main__':
    main()