1  """ Import Qt in a manner suitable for an IPython kernel.
   2  
   3  This is the import used for the `gui=qt` or `matplotlib=qt` initialization.
   4  
   5  Import Priority:
   6  
   7  if Qt has been imported anywhere else:
   8     use that
   9  
  10  if matplotlib has been imported and doesn't support v2 (<= 1.0.1):
  11      use PyQt4 @v1
  12  
  13  Next, ask QT_API env variable
  14  
  15  if QT_API not set:
  16      ask matplotlib what it's using. If Qt4Agg or Qt5Agg, then use the
  17          version matplotlib is configured with
  18  
  19      else: (matplotlib said nothing)
  20          # this is the default path - nobody told us anything
  21          try in this order:
  22              PyQt default version, PySide, PyQt5
  23  else:
  24      use what QT_API says
  25  
  26      Note that %gui's implementation will always set a `QT_API`, see
  27      `IPython.terminal.pt_inputhooks.get_inputhook_name_and_func`
  28  
  29  """
  30  # NOTE: This is no longer an external, third-party module, and should be
  31  # considered part of IPython. For compatibility however, it is being kept in
  32  # IPython/external.
  33  
  34  import os
  35  import sys
  36  
  37  from IPython.external.qt_loaders import (
  38      load_qt,
  39      loaded_api,
  40      enum_factory,
  41      # QT6
  42      QT_API_PYQT6,
  43      QT_API_PYSIDE6,
  44      # QT5
  45      QT_API_PYQT5,
  46      QT_API_PYSIDE2,
  47      # QT4
  48      QT_API_PYQT,
  49      QT_API_PYSIDE,
  50      # default
  51      QT_API_PYQT_DEFAULT,
  52  )
  53  
  54  _qt_apis = (
  55      # QT6
  56      QT_API_PYQT6,
  57      QT_API_PYSIDE6,
  58      # QT5
  59      QT_API_PYQT5,
  60      QT_API_PYSIDE2,
  61      # default
  62      QT_API_PYQT_DEFAULT,
  63  )
  64  
  65  
  66  def matplotlib_options(mpl):
  67      """Constraints placed on an imported matplotlib."""
  68      if mpl is None:
  69          return
  70      backend = mpl.rcParams.get('backend', None)
  71      if backend == 'Qt4Agg':
  72          mpqt = mpl.rcParams.get('backend.qt4', None)
  73          if mpqt is None:
  74              return None
  75          if mpqt.lower() == 'pyside':
  76              return [QT_API_PYSIDE]
  77          elif mpqt.lower() == 'pyqt4':
  78              return [QT_API_PYQT_DEFAULT]
  79          elif mpqt.lower() == 'pyqt4v2':
  80              return [QT_API_PYQT]
  81          raise ImportError("unhandled value for backend.qt4 from matplotlib: %r" %
  82                            mpqt)
  83      elif backend == 'Qt5Agg':
  84          mpqt = mpl.rcParams.get('backend.qt5', None)
  85          if mpqt is None:
  86              return None
  87          if mpqt.lower() == 'pyqt5':
  88              return [QT_API_PYQT5]
  89          raise ImportError("unhandled value for backend.qt5 from matplotlib: %r" %
  90                            mpqt)
  91  
  92  def get_options():
  93      """Return a list of acceptable QT APIs, in decreasing order of preference."""
  94      #already imported Qt somewhere. Use that
  95      loaded = loaded_api()
  96      if loaded is not None:
  97          return [loaded]
  98  
  99      mpl = sys.modules.get("matplotlib", None)
 100  
 101      if mpl is not None and tuple(mpl.__version__.split(".")) < ("1", "0", "2"):
 102          # 1.0.1 only supports PyQt4 v1
 103          return [QT_API_PYQT_DEFAULT]
 104  
 105      qt_api = os.environ.get('QT_API', None)
 106      if qt_api is None:
 107          #no ETS variable. Ask mpl, then use default fallback path
 108          return matplotlib_options(mpl) or [
 109              QT_API_PYQT_DEFAULT,
 110              QT_API_PYQT6,
 111              QT_API_PYSIDE6,
 112              QT_API_PYQT5,
 113              QT_API_PYSIDE2,
 114          ]
 115      elif qt_api not in _qt_apis:
 116          raise RuntimeError("Invalid Qt API %r, valid values are: %r" %
 117                             (qt_api, ', '.join(_qt_apis)))
 118      else:
 119          return [qt_api]
 120  
 121  
 122  api_opts = get_options()
 123  QtCore, QtGui, QtSvg, QT_API = load_qt(api_opts)
 124  enum_helper = enum_factory(QT_API, QtCore)
 125