使用PageViewController时PDFKit zoomIn / Out函数损坏

Question

我有一个使用UIPageViewController而不是scrollView初始化的pdfView，以带有过渡动画的方式一页一页地导航

pdfView.usePageViewController(true, withViewOptions: nil)

代替

pdfView.displayMode = .singlePage

一切正常，包括捏到缩放功能，但我还需要对doubleTap手势做出反应以放大/缩小，这时pdfView拒绝工作。

     private func _initTapGestures() {
        // Defining various tap gesture
        singleTap = UITapGestureRecognizer(target: self, action: #selector(self.handleSingleTapGesture(gesture: )))
        singleTap.numberOfTapsRequired = 1

        self.addGestureRecognizer(singleTap)

        doubleTap = UITapGestureRecognizer(target: self, action: #selector(self.handleDoubleTapGesture(gesture: )))
        doubleTap.numberOfTapsRequired = 2
        // Prevent singleTap to be triggered in case of doubleTap
        singleTap.require(toFail: doubleTap)
        self.addGestureRecognizer(doubleTap)
    }

    // Handles double tap gesture
    @objc func handleDoubleTapGesture(gesture: UITapGestureRecognizer) -> Void {
        if !doubleTapZoomed {
            // Zoom in at an intermediate level
            _doubleTapZoomIn()
        } else {
            // Reset zoom level
            _doubleTapZoomOut()
        }
    }

    private func _doubleTapZoomIn() {
        doubleTapZoomed = true

        // Save the current maxScale factor
        let maxScaleFactorReset = self.maxScaleFactor

        // Set a new scale factor for an intermediate zoom in
        self.maxScaleFactor = 2.5

        while self.canZoomIn() {
            self.zoomIn(self)
        }

        // Reset max scale factor to let the user to zoom in even more
        self.maxScaleFactor = maxScaleFactorReset
    }

    private func _doubleTapZoomOut() {
        doubleTapZoomed = false

        while self.canZoomOut() {
            self.zoomOut(self)
        }
    }

当我使用pdfView的默认导航将代码反转回去时，效果很好，我可以通过双击来放大和缩小...

有人遇到过同样的问题吗？这是PDFKit错误吗？

谢谢。