ios 9 AVCaptureDevice设置焦点

Question

我正试着用前面的摄像机设定焦点。

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

    let screenSize = cameraView.bounds.size

    let frameSize:CGSize = view.frame.size

    if let touchPoint = touches.first {

        var location:CGPoint = touchPoint.locationInView(cameraView)

        print("Tap Location : X: \(location.x), Y: \(location.y)")

        if cameraManager.cameraDevice == .Front {
            print("Front camera is used")

            location.x = frameSize.width - location.x;
        }
        else {
            print("Back camera is used")
        }

        let x = location.x / frameSize.width
        let y = 1.0 - (location.x / frameSize.width)

        let focusPoint = CGPoint(x: x, y: y)

        print("POINT : X: \(x), Y: \(y)")


        let captureDevice = (AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo) as! [AVCaptureDevice]).filter{$0.position == .Front}.first

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

                let support:Bool = device.focusPointOfInterestSupported

                if support  {

                    print("focusPointOfInterestSupported: \(support)")

                    device.focusPointOfInterest = focusPoint

                    // device.focusMode = .ContinuousAutoFocus
                    device.focusMode = .AutoFocus
                    // device.focusMode = .Locked

                    device.unlockForConfiguration()

                    print("Focus point was set successfully")
                }
                else{
                    print("focusPointOfInterestSupported is not supported: \(support)")
                }
            }
            catch {
                // just ignore
                print("Focus point error")
            }
        }
    }
}

它适用于iphone6上的后摄像头.但是，当我激活前面的摄像机，它打了。focusPointOfInterestSupported总是返回false。

我怎样才能解决这个问题。我可以以编程方式设置焦点吗？

谢谢!

Answer 1

focusPointOfInterestSupported布尔值表示此设备的前置摄像机不支持以这种方式设置焦点。事实上，看起来iPhone 6的“iPhone”相机有一个固定的焦点。在iPhone 6 "FaceTime“相机的技术规格部分中没有提到”焦点“，但是在后面的"iSight”摄像头部分。此外，试图在靠近镜头的模糊物体上重新对焦(通过在相机应用程序中点击)似乎只是调整曝光，而不是对焦。

来源：ref/occ/instp/AVCaptureDevice/focusPointOfInterestSupported

来源：http://www.apple.com/iphone-6/specs/