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    "iOS: 16.0.0 -",
    "iPadOS: 16.0.0 -",
    "visionOS: 1.0.0 -"
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# DataScannerViewControllerDelegate

A delegate object that responds when people interact with items that the data
scanner recognizes.

```
@MainActor protocol DataScannerViewControllerDelegate : AnyObject
```

## Overview

Implement this protocol to handle when people tap recognized items and,
optionally, provide additional feedback when the data scanner updates the
recognized items.

## Topics

### Customizing highlighting

[`dataScanner(_:didAdd:allItems:)`](/documentation/VisionKit/DataScannerViewControllerDelegate/dataScanner(_:didAdd:allItems:))

Responds when the data scanner starts recognizing an item.

[`dataScanner(_:didUpdate:allItems:)`](/documentation/VisionKit/DataScannerViewControllerDelegate/dataScanner(_:didUpdate:allItems:))

Responds when the data scanner updates the geometry of an item it
recognizes.

[`dataScanner(_:didRemove:allItems:)`](/documentation/VisionKit/DataScannerViewControllerDelegate/dataScanner(_:didRemove:allItems:))

Responds when the data scanner stops recognizing an item.

### Zooming

[`dataScannerDidZoom(_:)`](/documentation/VisionKit/DataScannerViewControllerDelegate/dataScannerDidZoom(_:))

Responds when a person or your code changes the zoom factor.

### Tapping items

[`dataScanner(_:didTapOn:)`](/documentation/VisionKit/DataScannerViewControllerDelegate/dataScanner(_:didTapOn:))

Responds when a person taps an item that the data scanner recognizes.

### Handling errors

[`dataScanner(_:becameUnavailableWithError:)`](/documentation/VisionKit/DataScannerViewControllerDelegate/dataScanner(_:becameUnavailableWithError:))

Responds when the data scanner becomes unavailable and stops scanning.


---

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