如何将QGraphicsView缩放恢复至100％，即程序启动时的缩放比例？

Question

所以，到目前为止，我有这样的代码：

from PyQt4 import QtGui, QtCore 

class MyFrame(QtGui.QGraphicsView): 
    """ 
     Python PyQt: How can I move my widgets on the window with mouse? 
     https://stackoverflow.com/questions/12213391/python-pyqt-how-can-i-move-my-widgets-on-the-window-with-mouse 
    """ 
    def __init__(self, parent = None): 
     super(MyFrame, self).__init__(parent) 

     scene = QtGui.QGraphicsScene() 
     self.setScene(scene) 
     self.resize(400, 340) 

     # http://pyqt.sourceforge.net/Docs/PyQt4/qpen.html 
     pencil = QtGui.QPen(QtCore.Qt.black, 1) 
     pencil.setStyle(QtCore.Qt.SolidLine) 

     scene.addLine(QtCore.QLineF(0, -50, 0, 50), pencil) 
     scene.addLine(QtCore.QLineF(-50, 0, 50, 0), pencil) 

     fitInViewButton = QtGui.QPushButton('Fit In View', self) 
     fitInViewButton.clicked.connect(self.handleFitInView) 

     scene.addWidget(fitInViewButton) 

    def handleFitInView(self): 
     # Auto scale a QGraphicsView 
     # http://www.qtcentre.org/threads/42917-Auto-scale-a-QGraphicsView 
     self.ensureVisible (self.scene().itemsBoundingRect()) 
     self.fitInView(self.scene().itemsBoundingRect(), QtCore.Qt.KeepAspectRatio) 

    def wheelEvent(self, event): 
     """ 
      PyQT4 WheelEvent? how to detect if the wheel have been use? 
      https://stackoverflow.com/questions/9475772/pyqt4-wheelevent-how-to-detect-if-the-wheel-have-been-use 

      QGraphicsView Zooming in and out under mouse position using mouse wheel 
      https://stackoverflow.com/questions/19113532/qgraphicsview-zooming-in-and-out-under-mouse-position-using-mouse-wheel 
     """ 

     # Zoom Factor 
     zoomInFactor = 1.1 
     zoomOutFactor = 1/zoomInFactor 

     # Set Anchors 
     self.setTransformationAnchor(QtGui.QGraphicsView.NoAnchor) 
     self.setResizeAnchor(QtGui.QGraphicsView.NoAnchor) 

     # Save the scene pos 
     oldPos = self.mapToScene(event.pos()) 

     # Zoom 
     if event.delta() > 0: 
      zoomFactor = zoomInFactor 
     else: 
      zoomFactor = zoomOutFactor 
     self.scale(zoomFactor, zoomFactor) 

     # Get the new position 
     newPos = self.mapToScene(event.pos()) 

     # Move scene to old position 
     delta = newPos - oldPos 
     self.translate(delta.x(), delta.y()) 

if (__name__ == '__main__'): 
    app = QtGui.QApplication([]) 
    f = MyFrame() 
    f.show() 
    app.exec_() 

它产生这个窗口最初打开，如：

不过后者我可以放大，如：

然后，我想有一个重置缩放按钮，将缩放设置为默认缩放时，该程序打开：

但按钮我有现在只拟合可见部分的全屏幕，而不是恢复原来的缩放，鼠标缩放滚动后：

Answer 1

重置索引则必须重新改造：

{your_graphicsview}.setTransform(QtGui.QTransform())