def _height_and_width(self):
"""Return a tuple of (terminal height, terminal width).
Start by trying TIOCGWINSZ (Terminal I/O-Control: Get Window Size),
falling back to environment variables (LINES, COLUMNS), and returning
(None, None) if those are unavailable or invalid.
"""
# tigetnum('lines') and tigetnum('cols') update only if we call
# setupterm() again.
for descriptor in self._init_descriptor, sys.__stdout__:
try:
return struct.unpack(
'hhhh', ioctl(descriptor, TIOCGWINSZ, '\000' * 8))[0:2]
except IOError:
# when the output stream or init descriptor is not a tty, such
# as when when stdout is piped to another program, fe. tee(1),
# these ioctls will raise IOError
pass
try:
return int(environ.get('LINES')), int(environ.get('COLUMNS'))
except TypeError:
return None, None
评论列表
文章目录