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Qr.Code

A QR code design studio in two implementations, sharing a payload vocabulary, a scanability model and a design language.

• iOS app — Sources/, Tests/, ShareExtension/. Swift 6, SwiftUI and Vision, targeting iOS 27; generates and scans QR, Aztec, PDF417, Code 128, EAN-13 and EAN-8.
• Web studio — web/. React 19, TypeScript and Vite; adds SVG export and bulk CSV generation. This is the app the iOS edition is a port of.

Both are offline-first: nothing you type, scan or generate leaves the device.

Scanability

Most QR tools will produce an unreadable code without warning. This one scores the design before export — contrast, module density, quiet zone, logo occlusion, styling cost — and reports the checks behind the score.

The score is backed by tests rather than judgement. RoundTripTests renders a symbol and decodes it with the same Vision framework real scanners use, across every module style, every error-correction level, gradients, logo sizes and each symbology. The logo slider's 0.35 ceiling is asserted decodable, so a change that breaks scannability fails the build.

Features

Payload types (12) — URL, text, Wi-Fi credentials, contact card, email, SMS, phone, geo, calendar event, Bitcoin payment, WhatsApp, and a raw mode for anything a scanner understands (SEPA/EPC transfers, deep links, proprietary schemes).

Symbologies (6) — QR, Aztec, PDF417, Code 128, EAN-13, EAN-8. EAN check digits are verified.

Styling — seven module shapes (square, rounded, smooth, dots, classy, leaf and fluid); rounded or circular finder frames; gradients; transparent backgrounds; centre logos; a theme gallery. Styled output is drawn as vector paths from the symbol matrix, so it stays sharp at any export size.

Export — SVG for print (QR codes), PNG up to 4096 px, and a print-sized PDF rasterised at 2048 px.

Batch — paste a list, get one PDF with a page per code, each page labelled with the payload it encodes. The web studio writes individual files into a ZIP; on iOS a single print-ready document needs no archive format, and the difference is deliberate rather than missing.

Context Band — an optional strip below the code showing a call to action and the destination, so a scan target is visible before scanning. The label is derived from the payload type; a Wi-Fi password is never printed.

System integration — App Intents for Siri and Shortcuts, and a share extension for turning a page or selected text into a code.

Scanner — camera, photo library and clipboard input. Decodes QR, Aztec, PDF417, Code 128, EAN and Data Matrix.

Architecture

Layer	Files	Responsibility
Model and encoding	Models.swift, PayloadBuilder.swift, EANEncoder.swift, Scanability.swift	Payload construction, EAN check digits, Bitcoin address checksums, scanability rules. Imports Foundation and CryptoKit only, so it is testable without a simulator.
Rendering	QRRenderer.swift, StyledQRRenderer.swift	Integer-pixel-per-module rasterisation, the vector path renderer, logo composition, the Context Band, PNG and PDF output.
Capture	ScanViews.swift	AVFoundation camera, Vision decoding, permission states.
Interface	QRFlowApp.swift, AppModel.swift, CreateViews.swift, CreateFormViews.swift, HistoryViews.swift, ComponentViews.swift, OnboardingViews.swift	One @Observable model holds state, navigation and persistence. The bar carries three destinations — Create, Design, Library — and the scanner opens as a camera cover rather than claiming a fourth.
Integration	QRFlowIntents.swift, ShareExtension/	App Intents and the share extension, built against the same renderer.

Constraints held throughout: no third-party dependencies, no network code, and no UI imports below the view layer.

Build

Requires Xcode 27; the deployment target is iOS 27.0.

open QRFlow.xcodeproj

Tests

xcodebuild -project QRFlow.xcodeproj -scheme QRFlow \
  -destination 'platform=iOS Simulator,name=iPhone 18 Pro' test

Replace the destination with an installed simulator (xcrun simctl list devices available). 70 tests, all passing.

The web studio carries its own suite: cd web && npm run verify runs the linter, 17 tests and a production build.

Area	Coverage
Round trips	Every module style × every error-correction level, gradients, dense payloads, and the linear symbologies — each rendered and decoded with Vision.
Logo ceiling	Decodability asserted up to the 0.35 the interface allows.
Payload correctness	Wi-Fi escaping, vCard CRLF and value escaping, wrapped and deterministic iCalendar records, WhatsApp encoding.
Bitcoin addresses	Base58Check and bech32/bech32m checksums. An invalid address is refused rather than encoded.
Scanability	Contrast, GS1 quiet zones per symbology, density and occlusion thresholds, preset contrast guarantees.

Accessibility

Toasts are announced to VoiceOver. Tappable rows are Buttons, so Switch Control and Full Keyboard Access can reach them. Controls containing text — the tab capsule, theme thumbnails — scale with Dynamic Type.

Privacy

The project contains no networking code. Camera images are decoded on device and never leave it. The privacy manifest declares one UserDefaults reason (CA92.1).

Known limitations

• iOS 27.0 minimum. The floor tracks the current release; older phones are out by choice, without #available fallbacks.
• The Siri and Shortcuts intent stores the Wi-Fi password in plain text. Shortcuts persists every parameter in the shortcut definition and its run history, and an app cannot mask or exclude it. The in-app field is a SecureField; that one is the system's to store.
• The share extension is verified by compilation only. The close button now lives in the extension's own view hierarchy; dismissing it on a device has not been tested.
• Screenshots are light appearance only. They are captured headlessly through the -ui-* launch hooks in AppModel, so regenerating them is a script rather than a manual pass.
• Page curvature is not corrected, only perspective.
• VNDetectBarcodesRequestRevision1 is deprecated but still used in tests: newer revisions require an inference context that headless simulators cannot create.

Licence

MIT. See LICENSE.