edge_detector 1.0.3

Edge detector plugin based on google ml kit object detection. Allows basic edge detection for given image.

example/lib/main.dart

import 'dart:io';

import 'package:edge_detector/edge_detector.dart';
import 'package:edge_detector_example/widgets/widgets.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import 'package:image_picker/image_picker.dart';
import 'package:path_provider/path_provider.dart';

void main() {
  runApp(const ExampleApp());
}

class ExampleApp extends StatelessWidget {
  const ExampleApp({
    super.key,
  });

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: ExamplePage(),
    );
  }
}

class ExamplePage extends StatefulWidget {
  const ExamplePage({
    super.key,
  });

  @override
  State<ExamplePage> createState() => _ExamplePageState();
}

class _ExamplePageState extends State<ExamplePage> {
  static final GlobalKey _imageKey = GlobalKey();

  File? _imageFile;
  List<Offset>? _edges;

  @override
  void initState() {
    super.initState();
    _setInitialImage();
  }

  @override
  Widget build(BuildContext context) {
    final imageFile = _imageFile;
    final edges = _edges;
    return Scaffold(
      appBar: AppBar(
        title: const Text('Edge Detector Example'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16).copyWith(
          bottom: MediaQuery.of(context).padding.bottom + 16,
        ),
        child: ListView(
          children: [
            Row(
              children: [
                _ActionButton(
                  label: 'Pick image',
                  onPressed: _pickImage,
                ),
                const SizedBox(width: 16),
                _ActionButton(
                  label: 'Detect edges',
                  onPressed: _detectEdges,
                ),
              ],
            ),
            const SizedBox(height: 16),
            if (imageFile != null)
              Stack(
                children: [
                  Image.file(
                    imageFile,
                    key: _imageKey,
                    fit: BoxFit.contain,
                  ),
                  if (edges != null) Lines(edges),
                ],
              ),
          ],
        ),
      ),
    );
  }

  Future<void> _setInitialImage() async {
    final bytes = await rootBundle.load('assets/images/1.jpg');
    final imageData =
        bytes.buffer.asUint8List(bytes.offsetInBytes, bytes.lengthInBytes);
    final directory = (await getTemporaryDirectory()).path;
    final path = '$directory/edge-detector-demo-image.jpg';
    final file = File(path);
    await file.writeAsBytes(imageData);
    setState(() => _imageFile = file);
  }

  Future<void> _pickImage() async {
    final image = await ImagePicker().pickImage(source: ImageSource.gallery);
    if (image == null) return;
    setState(() => _imageFile = File(image.path));
  }

  Future<void> _detectEdges() async {
    final imageFile = _imageFile;
    if (imageFile == null) return;

    final originalImageEdges = await EdgeDetector().detectEdges(imageFile);
    if (originalImageEdges == null) return;
    final widgetEdges = await originalImageEdges.toWidgetEdges(
      imageKey: _imageKey,
      originalImageFile: imageFile,
    );

    setState(() => _edges = widgetEdges.values);
  }
}

class _ActionButton extends StatelessWidget {
  const _ActionButton({
    required this.label,
    required this.onPressed,
  });

  final String label;
  final VoidCallback onPressed;

  @override
  Widget build(BuildContext context) {
    return Expanded(
      child: ElevatedButton(
        onPressed: onPressed,
        style: ElevatedButton.styleFrom(
          fixedSize: const Size.fromHeight(56),
        ),
        child: Text(label),
      ),
    );
  }
}