QRCodeGenerator

QRCodeGenerator is a finished SwiftUI demo app that generates a scannable QR code from text or a URL entered by the user.

It is designed as the complete sample project that accompanies a focused blog post about the reusable QRCodeGenerator helper. The post can stay small and teach the Core Image technique, while this app shows the surrounding user experience needed for a polished demo.

You can find the blog post on my website.

What the App Demonstrates

• Generating a QR code from a String using Core Image.
• Wrapping QR generation in a small reusable QRCodeGenerator enum.
• Displaying a crisp, non-blurry QR code in SwiftUI.
• Separating draft input from the committed generated value.
• Handling empty input and failed QR generation gracefully.
• Resetting the interface back to a clean state.
• Sharing a generated image with the system share sheet.
• Rendering a share image that includes both the QR code and its source text.

Project Structure

• QRCodeGenerator/QRCodeGenerator.swift contains the reusable QR code generation logic.
• QRCodeGenerator/ContentView.swift contains the app UI, preview state, reset behavior, and share flow.
• QRCodeGenerator/QRCodeGeneratorApp.swift is the SwiftUI app entry point.
• QRCodeGenerator/Assets.xcassets contains the app assets.

Core QR Code Helper

The central teaching piece is the QRCodeGenerator enum:

@MainActor
enum QRCodeGenerator {
    private static let context = CIContext()

    static func image(from text: String) -> Image? {
        guard let uiImage = uiImage(from: text) else { return nil }
        return Image(uiImage: uiImage)
    }

    static func uiImage(from text: String) -> UIImage? {
        let filter = CIFilter.qrCodeGenerator()
        filter.message = Data(text.utf8)
        filter.correctionLevel = "M"

        guard let outputImage = filter.outputImage else { return nil }

        let scaledImage = outputImage.transformed(
            by: CGAffineTransform(scaleX: 12, y: 12)
        )

        guard let cgImage = context.createCGImage(scaledImage, from: scaledImage.extent) else {
            return nil
        }

        return UIImage(cgImage: cgImage)
    }
}

The app uses uiImage(from:) because the generated QR code is displayed in SwiftUI and also passed into a custom sharing renderer.

User Flow

1. Enter text or a URL.
2. Tap Generate QR Code.
3. The app trims whitespace and commits the text as the generated value.
4. A QR code preview appears.
5. Use the share button to export a rendered image containing the QR code and source text.
6. Tap Reset or the clear button to return to an empty state.

Requirements

• Xcode 16 or later
• iOS 18 or later recommended
• SwiftUI
• Core Image
• UIKit for UIImage, image rendering, and UIActivityViewController

No third-party dependencies are required.

Build and Run

1. Open QRCodeGenerator.xcodeproj in Xcode.
2. Select the QRCodeGenerator scheme.
3. Run the app on an iOS Simulator or connected iOS device.