Allow freeform image annotation resizing in Swift for iOS

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//
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//  Copyright © 2017-2026 PSPDFKit GmbH. All rights reserved.
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//
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//  The Nutrient sample applications are licensed with a modified BSD license.
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//  Please see License for details. This notice may not be removed from this file.
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//
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import PSPDFKit
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import PSPDFKitUI
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class FloatingStampsExample: Example {
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    override init() {
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        super.init()
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        contentDescription = "Stamp annotations that have a fixed size and do not zoom with the page."
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        category = .annotations
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        priority = 2000
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    }
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    override func invoke(with delegate: ExampleRunnerDelegate) -> UIViewController {
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        let document = AssetLoader.writableDocument(for: .welcome, overrideIfExists: false)
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        // Register our custom annotation provider as a subclass before any action with a document is carried out.
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        // All stamp annotations added to this document using the example will not be zoomed in.
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        document.overrideClass(PDFFileAnnotationProvider.self, with: NoZoomAnnotationProvider.self)
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        let controller = PDFViewController(document: document)
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        return controller
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    }
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}
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private class NoZoomAnnotationProvider: PDFFileAnnotationProvider {
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    override func add(_ annotations: [Annotation], options: [AnnotationManager.ChangeBehaviorKey: Any]? = nil) -> [Annotation]? {
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        // Add the `noZoom` flag to all stamp annotations so they are not zoomed with the page.
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        for annotation in annotations where annotation is StampAnnotation {
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            annotation.flags.update(with: .noZoom)
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        }
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        return super.add(annotations, options: options)
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    }
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}