qtpy/__init__.py

   1 # -*- coding: utf-8 -*-
   2 #
   3 # Copyright © 2009- The Spyder Development Team
   4 # Copyright © 2014-2015 Colin Duquesnoy
   5 #
   6 # Licensed under the terms of the MIT License
   7 # (see LICENSE.txt for details)
   8
   9 """
  10 **QtPy** is a shim over the various Python Qt bindings. It is used to write
  11 Qt binding indenpendent libraries or applications.
  12
  13 If one of the APIs has already been imported, then it will be used.
  14
  15 Otherwise, the shim will automatically select the first available API (PyQt5,
  16 PySide2, PyQt4 and finally PySide); in that case, you can force the use of one
  17 specific bindings (e.g. if your application is using one specific bindings and
  18 you need to use library that use QtPy) by setting up the ``QT_API`` environment
  19 variable.
  20
  21 PyQt5
  22 =====
  23
  24 For PyQt5, you don't have to set anything as it will be used automatically::
  25
  26     >>> from qtpy import QtGui, QtWidgets, QtCore
  27     >>> print(QtWidgets.QWidget)
  28
  29
  30 PySide2
  31 ======
  32
  33 Set the QT_API environment variable to 'pyside2' before importing other
  34 packages::
  35
  36     >>> import os
  37     >>> os.environ['QT_API'] = 'pyside2'
  38     >>> from qtpy import QtGui, QtWidgets, QtCore
  39     >>> print(QtWidgets.QWidget)
  40
  41 PyQt4
  42 =====
  43
  44 Set the ``QT_API`` environment variable to 'pyqt' before importing any python
  45 package::
  46
  47     >>> import os
  48     >>> os.environ['QT_API'] = 'pyqt'
  49     >>> from qtpy import QtGui, QtWidgets, QtCore
  50     >>> print(QtWidgets.QWidget)
  51
  52 PySide
  53 ======
  54
  55 Set the QT_API environment variable to 'pyside' before importing other
  56 packages::
  57
  58     >>> import os
  59     >>> os.environ['QT_API'] = 'pyside'
  60     >>> from qtpy import QtGui, QtWidgets, QtCore
  61     >>> print(QtWidgets.QWidget)
  62
  63 """
  64
  65 from distutils.version import LooseVersion
  66 import os
  67 import platform
  68 import sys
  69 import warnings
  70
  71 # Version of QtPy
  72 from ._version import __version__
  73
  74
  75 class PythonQtError(RuntimeError):
  76     """Error raise if no bindings could be selected."""
  77     pass
  78
  79
  80 class PythonQtWarning(Warning):
  81     """Warning if some features are not implemented in a binding."""
  82     pass
  83
  84
  85 # Qt API environment variable name
  86 QT_API = 'QT_API'
  87
  88 # Names of the expected PyQt5 api
  89 PYQT5_API = ['pyqt5']
  90
  91 # Names of the expected PyQt4 api
  92 PYQT4_API = [
  93     'pyqt',  # name used in IPython.qt
  94     'pyqt4'  # pyqode.qt original name
  95 ]
  96
  97 # Names of the expected PySide api
  98 PYSIDE_API = ['pyside']
  99
 100 # Names of the expected PySide2 api
 101 PYSIDE2_API = ['pyside2']
 102
 103 # Detecting if a binding was specified by the user
 104 binding_specified = QT_API in os.environ
 105
 106 # Setting a default value for QT_API
 107 os.environ.setdefault(QT_API, 'pyqt5')
 108
 109 API = os.environ[QT_API].lower()
 110 initial_api = API
 111 assert API in (PYQT5_API + PYQT4_API + PYSIDE_API + PYSIDE2_API)
 112
 113 is_old_pyqt = is_pyqt46 = False
 114 PYQT5 = True
 115 PYQT4 = PYSIDE = PYSIDE2 = False
 116
 117 # When `FORCE_QT_API` is set, we disregard
 118 # any previously imported python bindings.
 119 if os.environ.get('FORCE_QT_API') is not None:
 120     if 'PyQt5' in sys.modules:
 121         API = initial_api if initial_api in PYQT5_API else 'pyqt5'
 122     elif 'PySide2' in sys.modules:
 123         API = initial_api if initial_api in PYSIDE2_API else 'pyside2'
 124     elif 'PyQt4' in sys.modules:
 125         API = initial_api if initial_api in PYQT4_API else 'pyqt4'
 126     elif 'PySide' in sys.modules:
 127         API = initial_api if initial_api in PYSIDE_API else 'pyside'
 128
 129
 130 if API in PYQT5_API:
 131     try:
 132         from PyQt5.QtCore import PYQT_VERSION_STR as PYQT_VERSION  # analysis:ignore
 133         from PyQt5.QtCore import QT_VERSION_STR as QT_VERSION  # analysis:ignore
 134         PYSIDE_VERSION = None
 135
 136         if sys.platform == 'darwin':
 137             macos_version = LooseVersion(platform.mac_ver()[0])
 138             if macos_version < LooseVersion('10.10'):
 139                 if LooseVersion(QT_VERSION) >= LooseVersion('5.9'):
 140                     raise PythonQtError("Qt 5.9 or higher only works in "
 141                                         "macOS 10.10 or higher. Your "
 142                                         "program will fail in this "
 143                                         "system.")
 144             elif macos_version < LooseVersion('10.11'):
 145                 if LooseVersion(QT_VERSION) >= LooseVersion('5.11'):
 146                     raise PythonQtError("Qt 5.11 or higher only works in "
 147                                         "macOS 10.11 or higher. Your "
 148                                         "program will fail in this "
 149                                         "system.")
 150
 151             del macos_version
 152     except ImportError:
 153         API = os.environ['QT_API'] = 'pyside2'
 154
 155 if API in PYSIDE2_API:
 156     try:
 157         from PySide2 import __version__ as PYSIDE_VERSION  # analysis:ignore
 158         from PySide2.QtCore import __version__ as QT_VERSION  # analysis:ignore
 159
 160         PYQT_VERSION = None
 161         PYQT5 = False
 162         PYSIDE2 = True
 163
 164         if sys.platform == 'darwin':
 165             macos_version = LooseVersion(platform.mac_ver()[0])
 166             if macos_version < LooseVersion('10.11'):
 167                 if LooseVersion(QT_VERSION) >= LooseVersion('5.11'):
 168                     raise PythonQtError("Qt 5.11 or higher only works in "
 169                                         "macOS 10.11 or higher. Your "
 170                                         "program will fail in this "
 171                                         "system.")
 172
 173             del macos_version
 174     except ImportError:
 175         API = os.environ['QT_API'] = 'pyqt'
 176
 177 if API in PYQT4_API:
 178     try:
 179         import sip
 180         try:
 181             sip.setapi('QString', 2)
 182             sip.setapi('QVariant', 2)
 183             sip.setapi('QDate', 2)
 184             sip.setapi('QDateTime', 2)
 185             sip.setapi('QTextStream', 2)
 186             sip.setapi('QTime', 2)
 187             sip.setapi('QUrl', 2)
 188         except (AttributeError, ValueError):
 189             # PyQt < v4.6
 190             pass
 191         from PyQt4.Qt import PYQT_VERSION_STR as PYQT_VERSION  # analysis:ignore
 192         from PyQt4.Qt import QT_VERSION_STR as QT_VERSION  # analysis:ignore
 193         PYSIDE_VERSION = None
 194         PYQT5 = False
 195         PYQT4 = True
 196     except ImportError:
 197         API = os.environ['QT_API'] = 'pyside'
 198     else:
 199         is_old_pyqt = PYQT_VERSION.startswith(('4.4', '4.5', '4.6', '4.7'))
 200         is_pyqt46 = PYQT_VERSION.startswith('4.6')
 201
 202 if API in PYSIDE_API:
 203     try:
 204         from PySide import __version__ as PYSIDE_VERSION  # analysis:ignore
 205         from PySide.QtCore import __version__ as QT_VERSION  # analysis:ignore
 206         PYQT_VERSION = None
 207         PYQT5 = PYSIDE2 = False
 208         PYSIDE = True
 209     except ImportError:
 210         raise PythonQtError('No Qt bindings could be found')
 211
 212 # If a correct API name is passed to QT_API and it could not be found,
 213 # switches to another and informs through the warning
 214 if API != initial_api and binding_specified:
 215     warnings.warn('Selected binding "{}" could not be found, '
 216                   'using "{}"'.format(initial_api, API), RuntimeWarning)
 217
 218 API_NAME = {'pyqt5': 'PyQt5', 'pyqt': 'PyQt4', 'pyqt4': 'PyQt4',
 219             'pyside': 'PySide', 'pyside2':'PySide2'}[API]
 220
 221 if PYQT4:
 222     import sip
 223     try:
 224         API_NAME += (" (API v{0})".format(sip.getapi('QString')))
 225     except AttributeError:
 226         pass