iOS - Swift -条形码扫描仪-扫描区域位于屏幕中心下方

Question

当条形码就在屏幕中央时，我无法扫描条形码，相反，我必须从屏幕中心稍下方的位置捕获条形码。

当我试图在横向模式下捕获条形码时，我必须扫描屏幕中心下方的条形码。我只想从屏幕的中间扫描条形码，而不考虑屏幕的方向。

Answer 1

一旦你开始在不同的方向上捕获，下面的代码就必须在主线程中调用。这段代码将帮助焦点区域位于屏幕的中心。

private var output: AVCaptureMetadataOutput?
private func configurePointOfInterests() {
    guard let device = self.captureDevice else { return }
    guard let videoPreviewLayer = self.videoPreviewLayer else { return }
    
    do {
        try device.lockForConfiguration()
        let point = CGPoint(x: self.view.bounds.midX, y: self.view.bounds.midY)
        let convPoint = videoPreviewLayer.captureDevicePointConverted(fromLayerPoint: point)
        
        device.exposurePointOfInterest = convPoint
        device.focusPointOfInterest = convPoint
        device.unlockForConfiguration()
    } catch {
        delegate?.cameraViewController(self, didReceiveError: error)
    }
}

private func configureRectOfInterest() {
    if let roi = videoPreviewLayer?.metadataOutputRectConverted(fromLayerRect: self.view.bounds) {
        output?.rectOfInterest = roi
    }
}

当您开始捕获self.captureSession.startRunning()时，如下所示在主线程中调用

            DispatchQueue.main.async {
                self.configurePointOfInterests()
                self.configureRectOfInterest()
            }