UniversalScanner

A small iOS app (Objective-C, UIKit) that scans barcodes/QR codes and reads a decimal number (e.g. a price tag) off a live camera feed using on-device text recognition — no third-party scanning library, everything is built on AVFoundation + Vision.

What it does

Two tabs (USCTabBarController):

• Scanner (USCScannerController) — a segmented control switches between two modes:
  • QR/Barcode — AVCaptureMetadataOutput decodes UPC-E, EAN-8/13, Code 39/93/128, PDF417, QR, Aztec, Interleaved 2 of 5, ITF-14 and Data Matrix. A yellow quad is drawn around the detected code once its center falls inside the on-screen cutout; the shutter button only becomes active while a code is centered.
  • Number — VNRecognizeTextRequest (Vision) runs on live AVCaptureVideoDataOutput frames, restricted to a region of interest, and extracts the first decimal number (regex [0-9]+\.[0-9]+) found in the frame — meant for reading a price off a tag.
  • Tapping the shutter freezes the session and hands the current value (currentQrOrBarCode or currentTextualCode) to the data service; tapping the result banner resumes scanning.
• History (USCHistoryController) — an in-memory, session-only list of everything captured from the Scanner tab. It implements the USCDataService protocol (- (void)addEntry:(NSString *)entry;) that USCScannerController is handed at init time — the scanner has no idea what happens to a captured value beyond that one method.

Camera preview is a custom AVCaptureVideoPreviewLayer-backed view (USCPreviewView) with an overlaid CAShapeLayer for the cutout mask and detection outline; USCCaptureButton draws its own shutter-button rings in -drawRect: instead of using image assets.

Portrait-only; device orientation is still tracked manually to keep the Vision region-of-interest and the QR/barcode drawing transform correct when the device is rotated in-hand.

Requirements

• Xcode with iOS 13.0+ SDK (IPHONEOS_DEPLOYMENT_TARGET = 13.0)
• A physical iOS device — AVCaptureSession/Vision need a camera, the Simulator can't run this (it builds fine on the Simulator, it just has no camera to scan with)
• No third-party dependencies — no CocoaPods/Carthage/SPM, only Apple frameworks (AVKit, Vision, CoreVideo)

Project layout

UniversalScanner/
├── AppDelegate.{h,m}            — sets up the tab bar tint and root view controller
├── USCTabBarController.{h,m}    — owns the two tabs, portrait-only
├── USCScannerController.{h,m}   — camera capture, QR/barcode + text-recognition modes
├── USCPreviewView.{h,m}         — AVCaptureVideoPreviewLayer-backed camera preview
├── USCCaptureButton.{h,m}       — self-drawn shutter button
├── USCDataService.h             — protocol the scanner reports captures through
├── USCHistoryController.{h,m}   — table view of captured values (implements USCDataService)
├── USCHistoryTableViewCell.*    — table cell (nib-based)
└── UIColor+Additions.{h,m}      — UIColor(Additions) category (fromHex:), used for the tab bar tint

License

MIT