PDF Highlight Annotation Blend Mode Menu in Swift for iOS

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//
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//  Copyright © 2019-2025 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 BlendModeMenuForMarkupAnnotationsExample: Example {
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    override init() {
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        super.init()
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        title = "Show Blend Mode menu item when selecting a highlight annotation"
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        contentDescription = "Shows how to add the Blend Mode menu item in the highlight annotation selection menu."
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        category = .annotations
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        priority = 204
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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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        document.annotationSaveMode = .embedded
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        // Add highlight annotation if there isn't one already.
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        let pageIndex: PageIndex = 0
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        let highlights = document.annotationsForPage(at: pageIndex, type: .highlight)
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        if highlights.isEmpty {
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            let textParser = document.textParserForPage(at: pageIndex)!
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            for word in textParser.words where word.stringValue == "PSPDFKit" {
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                guard let range = Range<Int>(word.range) else {
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                    continue
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                }
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                let highlightAnnotation = HighlightAnnotation.textOverlayAnnotation(with: [Glyph](textParser.glyphs[range]))!
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                highlightAnnotation.color = .yellow
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                highlightAnnotation.pageIndex = pageIndex
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                document.add(annotations: [highlightAnnotation])
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            }
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        }
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        let controller = BlendModeMenuForMarkupsViewController(document: document) {
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            // Configure the properties for highlight annotations to show the blend mode menu item.
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            var annotationProperties = $0.propertiesForAnnotations
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            annotationProperties[.highlight] = [[.blendMode, .color, .alpha]] as [[AnnotationStyle.Key]]
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            $0.propertiesForAnnotations = annotationProperties
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        }
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        return controller
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    }
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}
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private class BlendModeMenuForMarkupsViewController: PDFViewController {
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    override func viewDidAppear(_ animated: Bool) {
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        super.viewDidAppear(animated)
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        // Select the highlight annotation to show the Inspector menu.
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        let pageView = self.pageViewForPage(at: 0)
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        guard let highlightAnnotation = self.document?.annotationsForPage(at: pageIndex, type: .highlight).first else { return }
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        pageView?.select(annotations: [highlightAnnotation], presentMenu: true, animated: true)
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    }
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}