AVCaptureDevice Camera Zoom

Question

I have a simple AVCaptureSession running to get a camera feed in my app and take photos. How can I implement the \'pinch to zoom\' functionality using a UIGestureRecognize

Answer 1

In swift version, you can zoom in/out by simply passing scaled number on videoZoomFactor. Following code in UIPinchGestureRecognizer handler will solve the issue.

do {
    try device.lockForConfiguration()
    switch gesture.state {
    case .began:
        self.pivotPinchScale = device.videoZoomFactor
    case .changed:
        var factor = self.pivotPinchScale * gesture.scale
        factor = max(1, min(factor, device.activeFormat.videoMaxZoomFactor))
        device.videoZoomFactor = factor
    default:
        break
    }
    device.unlockForConfiguration()
} catch {
    // handle exception
}

In here, pivotPinchScale is a CGFloat property that declared in your controller somewhere.

You may also refer to following project to see how camera works with UIPinchGestureRecognizer. https://github.com/DragonCherry/CameraPreviewController