extras/qtpy/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 The shim will automatically select the first available API (PyQt5, PyQt4 and
  14 finally PySide).
  15
  16 You can force the use of one specific bindings (e.g. if your application is
  17 using one specific bindings and you need to use library that use QtPy) by
  18 setting up the ``QT_API`` environment variable.
  19
  20 PyQt5
  21 =====
  22
  23 For PyQt5, you don't have to set anything as it will be used automatically::
  24
  25     >>> from qtpy import QtGui, QtWidgets, QtCore
  26     >>> print(QtWidgets.QWidget)
  27
  28
  29 PyQt4
  30 =====
  31
  32 Set the ``QT_API`` environment variable to 'pyqt' before importing any python
  33 package::
  34
  35     >>> import os
  36     >>> os.environ['QT_API'] = 'pyqt'
  37     >>> from qtpy import QtGui, QtWidgets, QtCore
  38     >>> print(QtWidgets.QWidget)
  39
  40 PySide
  41 ======
  42
  43 Set the QT_API environment variable to 'pyside' before importing other
  44 packages::
  45
  46     >>> import os
  47     >>> os.environ['QT_API'] = 'pyside'
  48     >>> from qtpy import QtGui, QtWidgets, QtCore
  49     >>> print(QtWidgets.QWidget)
  50
  51 """
  52
  53 import os
  54
  55 # Version of QtPy
  56 from qtpy._version import __version__
  57
  58 #: Qt API environment variable name
  59 QT_API = 'QT_API'
  60 #: names of the expected PyQt5 api
  61 PYQT5_API = ['pyqt5']
  62 #: names of the expected PyQt4 api
  63 PYQT4_API = [
  64     'pyqt',  # name used in IPython.qt
  65     'pyqt4'  # pyqode.qt original name
  66 ]
  67 #: names of the expected PySide api
  68 PYSIDE_API = ['pyside']
  69
  70 os.environ.setdefault(QT_API, 'pyqt5')
  71 API = os.environ[QT_API]
  72 assert API in (PYQT5_API + PYQT4_API + PYSIDE_API)
  73
  74 is_old_pyqt = is_pyqt46 = False
  75 PYQT5 = True
  76 PYQT4 = PYSIDE = False
  77
  78
  79 class PythonQtError(Exception):
  80     """Error raise if no bindings could be selected"""
  81     pass
  82
  83
  84 if API in PYQT5_API:
  85     try:
  86         from PyQt5.Qt import PYQT_VERSION_STR as PYQT_VERSION  # analysis:ignore
  87         from PyQt5.Qt import QT_VERSION_STR as QT_VERSION  # analysis:ignore
  88         PYSIDE_VERSION = None
  89     except ImportError:
  90         API = os.environ['QT_API'] = 'pyqt'
  91
  92 if API in PYQT4_API:
  93     try:
  94         import sip
  95         try:
  96             sip.setapi('QString', 2)
  97             sip.setapi('QVariant', 2)
  98             sip.setapi('QDate', 2)
  99             sip.setapi('QDateTime', 2)
 100             sip.setapi('QTextStream', 2)
 101             sip.setapi('QTime', 2)
 102             sip.setapi('QUrl', 2)
 103         except AttributeError:
 104             # PyQt < v4.6
 105             pass
 106         from PyQt4.Qt import PYQT_VERSION_STR as PYQT_VERSION  # analysis:ignore
 107         from PyQt4.Qt import QT_VERSION_STR as QT_VERSION  # analysis:ignore
 108         PYSIDE_VERSION = None
 109         PYQT5 = False
 110         PYQT4 = True
 111     except ImportError:
 112         API = os.environ['QT_API'] = 'pyside'
 113     else:
 114         is_old_pyqt = PYQT_VERSION.startswith(('4.4', '4.5', '4.6', '4.7'))
 115         is_pyqt46 = PYQT_VERSION.startswith('4.6')
 116
 117 if API in PYSIDE_API:
 118     try:
 119         from PySide import __version__ as PYSIDE_VERSION  # analysis:ignore
 120         from PySide.QtCore import __version__ as QT_VERSION  # analysis:ignore
 121         PYQT_VERSION = None
 122         PYQT5 = False
 123         PYSIDE = True
 124     except ImportError:
 125         raise PythonQtError('No Qt bindings could be found')
 126
 127 API_NAME = {'pyqt5': 'PyQt5', 'pyqt': 'PyQt4', 'pyqt4': 'PyQt4',
 128             'pyside': 'PySide'}[API]
 129 if PYQT4:
 130         import sip
 131         try:
 132             API_NAME += (" (API v{0})".format(sip.getapi('QString')))
 133         except AttributeError:
 134             pass