问如何将平移事件从滚轮拖动改为鼠标右键拖动click+ at Pyqtgraph？

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class MainWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        uic.loadUi(_UI, self)  # Load the .ui file 

        axis = gl.GLAxisItem()
        grid = gl.GLGridItem()
        grid.scale(100, 100, 100)
        self.openGLWidget.addItem(grid)
        self.openGLWidget.addItem(axis)
        
        # installEventFilter
        self.openGLWidget.installEventFilter(self) 
        
    def eventFilter(self, source, event):
        if event.type() == QtCore.QEvent.MouseMove:
            if event.buttons() == QtCore.Qt.NoButton:
                print("Simple mouse motion")
                pass
            elif event.buttons() == QtCore.Qt.LeftButton:
                # print("Left click drag")
                pass
            elif event.buttons() == QtCore.Qt.RightButton:
                coef = 20  # Responsiveness of the pan

                xx = ((self.openGLWidget.size().width())/2)/coef
                yy = ((self.openGLWidget.size().height())/2)/coef
                self.pan((event.x()/coef)-xx, (event.y()/coef)-yy, 0)
                self.openGLWidget.updateGL()  
                # print("Right click drag")


        elif event.type() == QtCore.QEvent.MouseButtonPress:
            if event.button() == QtCore.Qt.RightButton:
                pass
                # print("Press!")
        return super(MainWindow, self).eventFilter(source, event)
    
    def pan(self, dx, dy, dz, relative='view'):
        """
        Moves the center (look-at) position while holding the camera in place. 
        
        ==============  =======================================================
        *relative*      String that determines the direction of dx,dy,dz. 
        
                        If "global", then the global coordinate system is used.
                        If "view", then the z axis is aligned with the view
                        If "view-upright", then x is in the global xy plane and
                        
                        points to the right side of the view, y is in the
                        global xy plane and orthogonal to x, and z points in
                        the global z direction.
        """
        # for backward compatibility:
        relative = {True: "view-upright", False: "global"}.get(relative, relative)
        
        if relative == 'global':
            self.openGLWidget.opts['center'] += QtGui.QVector3D(dx, dy, dz)
        elif relative == 'view-upright':
            cPos = self.openGLWidget.cameraPosition()
            cVec = self.openGLWidget.opts['center'] - cPos
            dist = cVec.length()  ## distance from camera to center
            xDist = dist * 2. * np.tan(0.5 * self.openGLWidget.opts['fov'] * np.pi / 180.)  ## approx. width of view at distance of center point
            xScale = xDist / self.width()
            zVec = QtGui.QVector3D(0,0,1)
            xVec = QtGui.QVector3D.crossProduct(zVec, cVec).normalized()
            yVec = QtGui.QVector3D.crossProduct(xVec, zVec).normalized()
            self.openGLWidget.opts['center'] = self.openGLWidget.opts['center'] + xVec * xScale * dx + yVec * xScale * dy + zVec * xScale * dz
        elif relative == 'view':
            # pan in plane of camera
            elev = np.radians(self.openGLWidget.opts['elevation'])
            azim = np.radians(self.openGLWidget.opts['azimuth'])
            fov = np.radians(self.openGLWidget.opts['fov'])
            dist = (self.openGLWidget.opts['center'] - self.openGLWidget.cameraPosition()).length()
            fov_factor = np.tan(fov / 2) * 2
            scale_factor = dist * fov_factor / self.width()
            z = scale_factor * np.cos(elev) * dy
            x = scale_factor * (np.sin(azim) * dx - np.sin(elev) * np.cos(azim) * dy)
            y = scale_factor * (np.cos(azim) * dx + np.sin(elev) * np.sin(azim) * dy)
            self.openGLWidget.opts['center'] += QtGui.QVector3D(x, -y, z)
        else:
            raise ValueError("relative argument must be global, view, or view-upright")
        
        self.update()