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Diffstat (limited to 'blessings/__init__.py')
| -rw-r--r-- | blessings/__init__.py | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/blessings/__init__.py b/blessings/__init__.py index b135e01..4506869 100644 --- a/blessings/__init__.py +++ b/blessings/__init__.py @@ -217,7 +217,13 @@ class Terminal(object): return self._height_and_width()[1] def _height_and_width(self): - """Return a tuple of (terminal height, terminal width).""" + """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__: @@ -225,8 +231,14 @@ class Terminal(object): 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 - return None, None # Should never get here + try: + return int(environ.get('LINES')), int(environ.get('COLUMNS')) + except TypeError: + return None, None @contextmanager def location(self, x=None, y=None): |