专注于自定义相机不工作一段时间

Question

我在我的应用程序中使用SwiftyCam作为CustomCamera。但在相机中，我注意到焦点有时不会改变。如果我点击远处的物体它不会快速聚焦，有时我需要移动我的手机。我无法找到发生这种情况的原因。以下是用户点击屏幕时的代码段。我还附上了图片以供比较。前两个图像是从自定义相机捕获的，最后两个是Apple默认相机。

@objc fileprivate func singleTapGesture(tap: UITapGestureRecognizer) {
    guard tapToFocus == true else {
        // Ignore taps
        return
    }

    let screenSize = previewLayer!.bounds.size
    let tapPoint = tap.location(in: previewLayer!)
    let x = tapPoint.y / screenSize.height
    let y = 1.0 - tapPoint.x / screenSize.width
    let focusPoint = CGPoint(x: x, y: y)

    if let device = videoDevice {
        do {
            try device.lockForConfiguration()

            if device.isFocusPointOfInterestSupported == true {
                device.focusPointOfInterest = focusPoint
                device.focusMode = .autoFocus
            }
            device.exposurePointOfInterest = focusPoint
            device.exposureMode = AVCaptureDevice.ExposureMode.continuousAutoExposure
            device.unlockForConfiguration()
            if exposureSlider != nil {
                exposureSlider.setValue(device.iso, animated: true)
            }
            //Call delegate function and pass in the location of the touch
            DispatchQueue.main.async {
                self.cameraDelegate?.swiftyCam(self, didFocusAtPoint: tapPoint)
                // add it manually show the slider and change value if there is no touch then remove it after some time
                if self.isexposureSliderHidden == true {
                    self.addSlider()
                }else{
                    self.removeSlider()
                }

            }
        }
        catch {
            // just ignore
        }
    }

}