add iOS BookTextView: UIViewRepresentable with NSAttributedString, highlight, tap-to-seek, scroll-to-offset

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Vorleser-iOS/BookTextView.swift

@@ -0,0 +1,75 @@
+import SwiftUI
+import UIKit
+import VorleserKit
+
+struct BookTextView: UIViewRepresentable {
+	let attributedText: NSAttributedString
+	let highlightRange: Range<Int>?
+	let onTapCharacter: (CharacterOffset) -> Void
+	var scrollToOffset: CharacterOffset?
+
+	func makeUIView(context: Context) -> UITextView {
+		let textView = UITextView()
+		textView.isEditable = false
+		textView.isSelectable = false
+		textView.textContainerInset = UIEdgeInsets(top: 16, left: 16, bottom: 16, right: 16)
+
+		let tap = UITapGestureRecognizer(target: context.coordinator, action: #selector(Coordinator.handleTap(_:)))
+		textView.addGestureRecognizer(tap)
+
+		return textView
+	}
+
+	func updateUIView(_ textView: UITextView, context: Context) {
+		let highlighted = NSMutableAttributedString(attributedString: attributedText)
+
+		if let range = highlightRange,
+		   range.lowerBound >= 0,
+		   range.upperBound <= attributedText.length {
+			let nsRange = NSRange(location: range.lowerBound, length: range.upperBound - range.lowerBound)
+			highlighted.addAttribute(.backgroundColor, value: UIColor.systemYellow.withAlphaComponent(0.3), range: nsRange)
+		}
+
+		if textView.attributedText != highlighted {
+			textView.attributedText = highlighted
+		}
+
+		if let range = highlightRange,
+		   range.lowerBound >= 0,
+		   range.upperBound <= attributedText.length {
+			let nsRange = NSRange(location: range.lowerBound, length: range.upperBound - range.lowerBound)
+			textView.scrollRangeToVisible(nsRange)
+		}
+
+		if let offset = scrollToOffset,
+		   offset >= 0,
+		   offset < attributedText.length {
+			let nsRange = NSRange(location: offset, length: 1)
+			textView.scrollRangeToVisible(nsRange)
+		}
+	}
+
+	func makeCoordinator() -> Coordinator {
+		Coordinator(onTapCharacter: onTapCharacter)
+	}
+
+	class Coordinator: NSObject {
+		let onTapCharacter: (CharacterOffset) -> Void
+
+		init(onTapCharacter: @escaping (CharacterOffset) -> Void) {
+			self.onTapCharacter = onTapCharacter
+		}
+
+		@objc func handleTap(_ gesture: UITapGestureRecognizer) {
+			guard let textView = gesture.view as? UITextView else { return }
+			let point = gesture.location(in: textView)
+			let characterIndex = textView.offset(
+				from: textView.beginningOfDocument,
+				to: textView.closestPosition(to: point) ?? textView.beginningOfDocument
+			)
+			if characterIndex < textView.attributedText.length {
+				onTapCharacter(characterIndex)
+			}
+		}
+	}
+}