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

Question

到目前为止，我有这个代码：

from PyQt4 import QtGui, QtCore

class MyFrame(QtGui.QGraphicsView):
    """
        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?
            

            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_()

它生成这个 window 最初打开为：

但是后者我可以像这样放大：

然后我想要一个重置缩放按钮，在程序打开时将缩放设置为默认缩放：

但是我现在的按钮只能全屏显示可见部分，鼠标滚动缩放后不会恢复原来的缩放：

Answer 1

要重置索引，您必须重置转换：

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

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

How to restore a QGraphicsView zoom to 100%, i.e., the zoom when the program started?

python

pyqt

pyqt4

qgraphicsview

qgraphicsscene