Pinch to zoom camera

Question

I\'m trying to make a pinch to zoom camera but I\'m encountering two problems. First is that it allows the user to zoom way too much in and way to much out, secondly when I take

Answer 1

You can avoid saving prevZoomFactor by simply resetting UIPinchGestureRecognizer.scale to 1 like this:

    @IBAction func pinchAction(_ sender: UIPinchGestureRecognizer) {
        guard let device = currentCaptureDevice else {return}
        var zoom = device.videoZoomFactor * sender.scale
        sender.scale = 1.0
        var error:NSError!
        do{
            try device.lockForConfiguration()
            defer {device.unlockForConfiguration()}
            if zoom >= device.minAvailableVideoZoomFactor && zoom <= device.maxAvailableVideoZoomFactor {
                device.videoZoomFactor = zoom
            }else{
                NSLog("Unable to set videoZoom: (max %f, asked %f)", device.activeFormat.videoMaxZoomFactor, zoom);
            }
        }catch error as NSError{
            NSLog("Unable to set videoZoom: %@", error.localizedDescription);
        }catch _{
        }
    }

This was recommended by Apple at a WWDC event I attended way back when gesture recognizers first came out.