Flutter Full Screen Scanner

A production-ready, highly optimized Flutter plugin for continuous, full-screen barcode and QR code scanning. Built with pure native implementations (CameraX and ML Kit on Android, AVFoundation on iOS) to ensure blazing fast, zero-jank performance.

Features

• Blazing Fast: Uses ML Kit on Android and native AVFoundation on iOS.
• Continuous Scanning: Capable of detecting and tracking multiple barcodes continuously in real-time.
• Customizable UI: We provide the camera feed, you provide the overlay. Draw whatever you want on top of the scanner using the overlayBuilder.
• Zero Flutter Camera Package Dependency: Fully native implementations mean no overhead and no memory leaks from the standard Flutter camera package.
• Duplicate Prevention: Built-in cache system to debounce duplicate scans.
• High Resolution Capture: Seamlessly capture uncompressed 1080p images of scanned barcodes.
• Dynamic Orientation: Perfectly handles device rotation without interrupting the scan flow.

Installation

Add the following to your pubspec.yaml:

dependencies:
  flutter_full_screen_scanner: ^1.0.8

Android Setup

Update your android/app/build.gradle to ensure your minSdkVersion is at least 21.

android {
    defaultConfig {
        minSdkVersion 21
    }
}

iOS Setup

Add the camera usage description to your ios/Runner/Info.plist:

<key>NSCameraUsageDescription</key>
<string>This app requires access to the camera to scan barcodes and QR codes.</string>

Usage

import 'package:flutter/material.dart';
import 'package:flutter_full_screen_scanner/flutter_full_screen_scanner.dart';

class ScannerScreen extends StatefulWidget {
  @override
  _ScannerScreenState createState() => _ScannerScreenState();
}

class _ScannerScreenState extends State<ScannerScreen> {
  final ScannerController _controller = ScannerController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: FullScreenScanner(
        controller: _controller,
        options: const ScannerOptions(
          allowDuplicate: false,
          duplicateDelay: 1500, // Debounce same barcode for 1.5s
          scanWindow: ScanWindow(widthFactor: 0.8, heightFactor: 0.3),
        ),
        onScan: (ScannerResult result) {
          print('Scanned: ${result.value} of type ${result.type}');
        },
        overlayBuilder: (context, state) {
          return ScannerCutoutOverlay(
            scanWindow: const ScanWindow(widthFactor: 0.8, heightFactor: 0.3),
            borderColor: state.barcodeDetected ? Colors.green : Colors.blue,
          );
        },
      ),
    );
  }
}

ScannerOptions

Configure the scanner settings via the ScannerOptions class:

• scanWindow: Restricts the active scan area (defined as a ScanWindow with coordinate factors from 0.0 to 1.0). Only barcodes fully visible and positioned entirely within this cutout area are detected.
• enableImageCapture: Set to false to disable retrieving barcode image bytes (imageBytes). Doing so disables raw image frame extraction and JPEG compression on the native thread, significantly reducing CPU usage and enabling smoother continuous scanning.
• allowDuplicate & duplicateDelay: Configure duplicate detection and cooling down periods.

Controller API

The ScannerController gives you full programmatic control over the hardware:

• pause(): Pauses the camera feed and scanner.
• resume(): Resumes the camera feed and scanner.
• stop(): Shuts down the scanner entirely.
• toggleFlash(): Turns the device torch on or off.
• switchCamera(): Flips between the front and back cameras.
• scanImage(String path): Scans a static image from the filesystem for barcodes.

Extensibility

This SDK is designed to be highly extensible. The overlayBuilder exposes the raw ScannerState on every frame, allowing you to draw bounding boxes, animate crosshairs, or display interactive UI elements perfectly aligned with the real world.