NavigationBarButton项目无法垂直对齐？

Question

您好我尝试在导航栏中对齐navigationbar按钮项目位置中心。我已经以编程方式更改了导航栏高度，因此我可以将标题与其工作正常对齐，但同样我尝试了leftbarbutton和rightbarbutton。它没有垂直对齐的中心。我已经以编程方式尝试了这些

标题对齐

self.navigationController!.navigationBar.setTitleVerticalPositionAdjustment(-15, forBarMetrics: .Default)

RightBarButton：

       let button: UIButton = UIButton(type: .Custom)
    button.setImage(buttonImage, forState: UIControlState.Normal)
    button.addTarget(self, action: #selector(self.toggleRight), forControlEvents: UIControlEvents.TouchUpInside)
    button.frame = CGRectMake(0, 0, 40, 40)
    let rightButton = UIBarButtonItem(customView: button)
 //   rightButton.imageInsets =  UIEdgeInsets(top: 20, left: 0, bottom: 0, right: 0)
    let negativeSpacer = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.FixedSpace, target: nil, action: nil)
    negativeSpacer.width = -10;
    self.navigationItem.rightBarButtonItems = [negativeSpacer ,rightButton ]

LeftBarButton：

        let button: UIButton = UIButton(type: .Custom)
    button.setImage(buttonImage, forState: UIControlState.Normal)
    button.addTarget(self, action: #selector(self.toggleLeft), forControlEvents: UIControlEvents.TouchUpInside)
    button.frame = CGRectMake(0, 0, 40, 40)
    let leftButton = UIBarButtonItem(customView: button)
    let negativeSpacer = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.FixedSpace, target: nil, action: nil)
    negativeSpacer.width = -10;
    self.navigationItem.leftBarButtonItems = [negativeSpacer,leftButton ]

请找截图。