__init__.py 文件源码

def cleanup():
    global _cleanupCalled
    if _cleanupCalled:
        return

    if not getConfigOption('exitCleanup'):
        return

    ViewBox.quit()  ## tell ViewBox that it doesn't need to deregister views anymore.

    ## Workaround for Qt exit crash:
    ## ALL QGraphicsItems must have a scene before they are deleted.
    ## This is potentially very expensive, but preferred over crashing.
    ## Note: this appears to be fixed in PySide as of 2012.12, but it should be left in for a while longer..
    if QtGui.QApplication.instance() is None:
        return
    import gc
    s = QtGui.QGraphicsScene()
    for o in gc.get_objects():
        try:
            if isinstance(o, QtGui.QGraphicsItem) and isQObjectAlive(o) and o.scene() is None:
                if getConfigOption('crashWarning'):
                    sys.stderr.write('Error: graphics item without scene. '
                        'Make sure ViewBox.close() and GraphicsView.close() '
                        'are properly called before app shutdown (%s)\n' % (o,))

                s.addItem(o)
        except RuntimeError:  ## occurs if a python wrapper no longer has its underlying C++ object
            continue
    _cleanupCalled = True