Image picker with compression

import 'dart:io';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';

class PhotoPickerController extends ChangeNotifier {
  PhotoPickerController({this.max = 6, this.maxEdge = 1600, this.quality = 80, this.maxBytes = 1500000});
  final int max, maxEdge, quality, maxBytes;
  final _picker = ImagePicker();
  final List<File> files = [];
  String? message;

  Future<void> fromGallery() async {
    final left = max - files.length;
    if (left <= 0) return _warn('You can add up to $max photos.');
    // limit/maxWidth/imageQuality make the plugin resize and re-encode natively.
    final picked = await _picker.pickMultiImage(
      maxWidth: maxEdge.toDouble(),
      maxHeight: maxEdge.toDouble(),
      imageQuality: quality,
      limit: left,
    );
    await _accept(picked);
  }

  Future<void> fromCamera() async {
    if (files.length >= max) return _warn('You can add up to $max photos.');
    final shot = await _picker.pickImage(
      source: ImageSource.camera,
      maxWidth: maxEdge.toDouble(),
      maxHeight: maxEdge.toDouble(),
      imageQuality: quality,
    );
    await _accept(shot == null ? [] : [shot]);
  }

  Future<void> _accept(List<XFile> picked) async {
    message = null;
    for (final x in picked) {
      if (files.length >= max) break;
      final f = File(x.path);
      if (await f.length() > maxBytes) {
        message = 'Some photos were still too large and were skipped.';
        continue;
      }
      files.add(f);
    }
    notifyListeners();
  }

  void remove(File f) {
    files.remove(f);
    notifyListeners();
  }

  void _warn(String text) {
    message = text;
    notifyListeners();
  }
}

class PhotoStrip extends StatelessWidget {
  const PhotoStrip({super.key, required this.controller});
  final PhotoPickerController controller;

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: controller,
      builder: (context, _) => Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
        Row(children: [
          OutlinedButton.icon(onPressed: controller.fromGallery, icon: const Icon(Icons.photo_library), label: const Text('Gallery')),
          const SizedBox(width: 8),
          OutlinedButton.icon(onPressed: controller.fromCamera, icon: const Icon(Icons.photo_camera), label: const Text('Camera')),
        ]),
        if (controller.message != null) Text(controller.message!),
        SizedBox(
          height: 88,
          child: ListView(scrollDirection: Axis.horizontal, children: [
            for (final f in controller.files)
              Stack(children: [
                Padding(
                  padding: const EdgeInsets.all(4),
                  child: ClipRRect(borderRadius: BorderRadius.circular(8), child: Image.file(f, width: 80, height: 80, fit: BoxFit.cover, cacheWidth: 160)),
                ),
                PositionedDirectional(end: 0, top: 0, child: InkWell(onTap: () => controller.remove(f), child: const Icon(Icons.cancel, size: 20))),
              ]),
          ]),
        ),
      ]),
    );
  }
}