text: # encoding: utf-8
  """
  Utilities for working with terminals.
  
  Authors:
  
  * Brian E. Granger
  * Fernando Perez
  * Alexander Belchenko (e-mail: bialix AT ukr.net)
  """
  
  # Copyright (c) IPython Development Team.
  # Distributed under the terms of the Modified BSD License.
  
  import os
  import sys
  import warnings
  try:
      from shutil import get_terminal_size as _get_terminal_size
  except ImportError:
      # use backport on Python 2
      from backports.shutil_get_terminal_size import get_terminal_size as _get_terminal_size
  
  from . import py3compat
  
  #-----------------------------------------------------------------------------
  # Code
  #-----------------------------------------------------------------------------
  
  # This variable is part of the expected API of the module:
  ignore_termtitle = True
  
  
  
  if os.name == 'posix':
      def _term_clear():
          os.system('clear')
  elif sys.platform == 'win32':
      def _term_clear():
          os.system('cls')
  else:
      def _term_clear():
          pass
  
  
  
  def toggle_set_term_title(val):
      """Control whether set_term_title is active or not.
  
      set_term_title() allows writing to the console titlebar.  In embedded
      widgets this can cause problems, so this call can be used to toggle it on
      or off as needed.
  
      The default state of the module is for the function to be disabled.
  
      Parameters
      ----------
        val : bool
          If True, set_term_title() actually writes to the terminal (using the
          appropriate platform-specific module).  If False, it is a no-op.
      """
      global ignore_termtitle
      ignore_termtitle = not(val)
  
  
  def _set_term_title(*args,**kw):
      """Dummy no-op."""
      pass
  
  
  def _set_term_title_xterm(title):
      """ Change virtual terminal title in xterm-workalikes """
      sys.stdout.write('\033]0;%s\007' % title)
  
  if os.name == 'posix':
      TERM = os.environ.get('TERM','')
      if TERM.startswith('xterm'):
          _set_term_title = _set_term_title_xterm
  elif sys.platform == 'win32':
      try:
          import ctypes
  
          SetConsoleTitleW = ctypes.windll.kernel32.SetConsoleTitleW
          SetConsoleTitleW.argtypes = [ctypes.c_wchar_p]
      
          def _set_term_title(title):
              """Set terminal title using ctypes to access the Win32 APIs."""
              SetConsoleTitleW(title)
      except ImportError:
          def _set_term_title(title):
              """Set terminal title using the 'title' command."""
              global ignore_termtitle
  
              try:
                  # Cannot be on network share when issuing system commands
                  curr = py3compat.getcwd()
                  os.chdir("C:")
                  ret = os.system("title " + title)
              finally:
                  os.chdir(curr)
              if ret:
                  # non-zero return code signals error, don't try again
                  ignore_termtitle = True
  
  
  def set_term_title(title):
      """Set terminal title using the necessary platform-dependent calls."""
      if ignore_termtitle:
          return
      _set_term_title(title)
  
  
  def freeze_term_title():
      warnings.warn("This function is deprecated, use toggle_set_term_title()")
      global ignore_termtitle
      ignore_termtitle = True
  
  
  def get_terminal_size(defaultx=80, defaulty=25):
      return _get_terminal_size((defaultx, defaulty))
  