Customization of Viewfinder, support for rectOfInterest

Sources/CodeScanner/CodeScanner.swift

@@ -82,6 +82,7 @@ public struct CodeScannerView: UIViewControllerRepresentable {
     public let manualSelect: Bool
     public let scanInterval: Double
     public let showViewfinder: Bool
+    public let useViewfinderAsRectOfInterest: Bool
     public let requiresPhotoOutput: Bool
     public var simulatedData = ""
     public var shouldVibrateOnSuccess: Bool
@@ -90,13 +91,15 @@ public struct CodeScannerView: UIViewControllerRepresentable {
     public var isGalleryPresented: Binding<Bool>
     public var videoCaptureDevice: AVCaptureDevice?
     public var completion: (Result<ScanResult, ScanError>) -> Void
+    private(set) var currentViewfinderStyle: AnyScannerViewfinderStyle = .init(style: .default)
 
     public init(
         codeTypes: [AVMetadataObject.ObjectType],
         scanMode: ScanMode = .once,
         manualSelect: Bool = false,
         scanInterval: Double = 2.0,
         showViewfinder: Bool = false,
+        useViewfinderAsRectOfInterest: Bool = false,
         requiresPhotoOutput: Bool = true,
         simulatedData: String = "",
         shouldVibrateOnSuccess: Bool = true,
@@ -110,6 +113,7 @@ public struct CodeScannerView: UIViewControllerRepresentable {
         self.scanMode = scanMode
         self.manualSelect = manualSelect
         self.showViewfinder = showViewfinder
+        self.useViewfinderAsRectOfInterest = useViewfinderAsRectOfInterest
         self.requiresPhotoOutput = requiresPhotoOutput
         self.scanInterval = scanInterval
         self.simulatedData = simulatedData
@@ -122,7 +126,11 @@ public struct CodeScannerView: UIViewControllerRepresentable {
     }
 
     public func makeUIViewController(context: Context) -> ScannerViewController {
-        return ScannerViewController(showViewfinder: showViewfinder, parentView: self)
+        return ScannerViewController(
+            showViewfinder: showViewfinder,
+            useViewfinderAsRectOfInterest: useViewfinderAsRectOfInterest,
+            parentView: self
+        )
     }
 
     public func updateUIViewController(_ uiViewController: ScannerViewController, context: Context) {
@@ -135,6 +143,11 @@ public struct CodeScannerView: UIViewControllerRepresentable {
         )
     }
 
+    public func viewfinderStyle<S>(_ style: S) -> Self where S: ScannerViewfinderStyle {
+        var copy = self
+        copy.currentViewfinderStyle = .init(style: style)
+        return copy
+    }
 }
 
 @available(macCatalyst 14.0, *)

Sources/CodeScanner/ScannerViewController.swift

@@ -8,7 +8,7 @@
 
 #if os(iOS)
 import AVFoundation
-import UIKit
+import SwiftUI
 
 @available(macCatalyst 14.0, *)
 extension CodeScannerView {
@@ -22,6 +22,7 @@ extension CodeScannerView {
         var didFinishScanning = false
         var lastTime = Date(timeIntervalSince1970: 0)
         private let showViewfinder: Bool
+        private let useViewfinderAsRectOfInterest: Bool
 
         let fallbackVideoCaptureDevice = AVCaptureDevice.default(for: .video)
 
@@ -34,14 +35,20 @@ extension CodeScannerView {
             }
         }
 
-        public init(showViewfinder: Bool = false, parentView: CodeScannerView) {
+        public init(
+            showViewfinder: Bool = false,
+            useViewfinderAsRectOfInterest: Bool = false,
+            parentView: CodeScannerView
+        ) {
             self.parentView = parentView
             self.showViewfinder = showViewfinder
+            self.useViewfinderAsRectOfInterest = useViewfinderAsRectOfInterest
             super.init(nibName: nil, bundle: nil)
         }
 
         required init?(coder: NSCoder) {
             self.showViewfinder = false
+            self.useViewfinderAsRectOfInterest = false
             super.init(coder: coder)
         }
 
@@ -104,15 +111,12 @@ extension CodeScannerView {
 
         var captureSession: AVCaptureSession?
         var previewLayer: AVCaptureVideoPreviewLayer!
-
-        private lazy var viewFinder: UIImageView? = {
-            guard let image = UIImage(named: "viewfinder", in: .module, with: nil) else {
-                return nil
-            }
-
-            let imageView = UIImageView(image: image)
-            imageView.translatesAutoresizingMaskIntoConstraints = false
-            return imageView
+
+        private lazy var viewFinder: UIHostingController<AnyView> = {
+            let vc = UIHostingController(rootView: parentView.currentViewfinderStyle.makeBody())
+            vc.view.translatesAutoresizingMaskIntoConstraints = false
+            vc.view.backgroundColor = .clear
+            return vc
         }()
 
         private lazy var manualCaptureButton: UIButton = {
@@ -144,6 +148,7 @@ extension CodeScannerView {
 
         override public func viewWillLayoutSubviews() {
             previewLayer?.frame = view.layer.bounds
+            updateRectOfInterest()
         }
 
         @objc func updateOrientation() {
@@ -187,7 +192,8 @@ extension CodeScannerView {
             previewLayer.videoGravity = .resizeAspectFill
             view.layer.addSublayer(previewLayer)
             addViewFinder()
-
+            updateRectOfInterest()
+
             reset()
 
             if !captureSession.isRunning {
@@ -276,17 +282,39 @@ extension CodeScannerView {
                 return
             }
         }
+
+        private func updateRectOfInterest() {
+            guard let captureSession, showViewfinder && useViewfinderAsRectOfInterest && previewLayer != nil else {
+                return
+            }
+
+            let rectSize = viewFinder.view.frame.size
+            let rectPointOnLayer = CGPoint(x: previewLayer.frame.midX - (rectSize.width / 2),
+                                           y: previewLayer.frame.midY - (rectSize.height / 2))
+            let rect = previewLayer.metadataOutputRectConverted(fromLayerRect: CGRect(origin: rectPointOnLayer, size: rectSize))
+
+            captureSession.outputs.compactMap { $0 as? AVCaptureMetadataOutput }.forEach {
+                $0.rectOfInterest = rect
+            }
+        }
 
         private func addViewFinder() {
-            guard showViewfinder, let imageView = viewFinder else { return }
-
-            view.addSubview(imageView)
-
+            guard showViewfinder else { return }
+
+            let viewfinderVC = viewFinder
+
+            viewfinderVC.willMove(toParent: self)
+            addChild(viewfinderVC)
+            view.addSubview(viewfinderVC.view)
+            viewfinderVC.didMove(toParent: self)
+
+            let desiredSize = viewfinderVC.sizeThatFits(in: view.bounds.size)
+
             NSLayoutConstraint.activate([
-                imageView.centerYAnchor.constraint(equalTo: view.centerYAnchor),
-                imageView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
-                imageView.widthAnchor.constraint(equalToConstant: 200),
-                imageView.heightAnchor.constraint(equalToConstant: 200),
+                viewfinderVC.view.centerYAnchor.constraint(equalTo: view.centerYAnchor),
+                viewfinderVC.view.centerXAnchor.constraint(equalTo: view.centerXAnchor),
+                viewfinderVC.view.widthAnchor.constraint(equalToConstant: desiredSize.width),
+                viewfinderVC.view.heightAnchor.constraint(equalToConstant: desiredSize.height),
             ])
         }
 

Sources/CodeScanner/ScannerViewfinderStyle.swift

@@ -0,0 +1,44 @@
+//
+//  ScannerViewfinderStyle.swift
+//  CodeScanner
+//
+//  Created by Bartłomiej Bukowiecki on 28/01/2025.
+//
+
+#if os(iOS)
+import SwiftUI
+
+public protocol ScannerViewfinderStyle {
+    associatedtype Content: View
+
+    @ViewBuilder func makeBody() -> Content
+}
+
+struct AnyScannerViewfinderStyle: ScannerViewfinderStyle {
+    private let wrappedBody: () -> AnyView
+
+    init<S>(style: S) where S: ScannerViewfinderStyle {
+        self.wrappedBody = {
+            AnyView(style.makeBody())
+        }
+    }
+
+    func makeBody() -> AnyView {
+        wrappedBody()
+    }
+}
+
+public struct DefaultScannerViewfinderStyle: ScannerViewfinderStyle {
+    public func makeBody() -> some View {
+        Image("viewfinder", bundle: .module)
+            .resizable()
+            .frame(width: 200, height: 200)
+    }
+}
+
+extension ScannerViewfinderStyle where Self == DefaultScannerViewfinderStyle {
+    public static var `default`: DefaultScannerViewfinderStyle {
+        DefaultScannerViewfinderStyle()
+    }
+}
+#endif