flutter_caesium_ffi 2.0.0

Fast, high-quality image compression, resize, conversion, and target-size optimization for Flutter mobile, desktop, and web, powered by libcaesium.

example/lib/main.dart

import 'dart:convert';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_caesium_ffi/flutter_caesium_ffi.dart';

void main() => runApp(const ExampleApp());

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

  @override
  State<ExampleApp> createState() => _ExampleAppState();
}

class _ExampleAppState extends State<ExampleApp> {
  static const String _samplePng =
      'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR4nGP6'
      'zwAAAgcBApocMXEAAAAASUVORK5CYII=';

  String _status = 'Press the button to run libcaesium.';
  bool _running = false;

  Future<void> _compressSample() async {
    setState(() {
      _running = true;
      _status = kIsWeb
          ? 'Compressing with WebAssembly…'
          : 'Compressing on a worker isolate…';
    });
    try {
      final Uint8List input = base64Decode(_samplePng);
      final CaesiumMemoryResult result = await FlutterCaesiumFfi.compress(
        input,
        options: const CaesiumOptions(png: PngOptions(optimize: true)),
      );
      final CaesiumMemoryResult targeted =
          await FlutterCaesiumFfi.compressToSize(
            input,
            maxOutputBytes: 128,
            returnSmallest: true,
          );
      final CaesiumMemoryResult converted = await FlutterCaesiumFfi.convert(
        input,
        format: CaesiumFormat.webp,
      );
      if (!_isWebp(converted.bytes)) {
        throw StateError('Conversion did not produce a WebP image.');
      }
      setState(() {
        _status =
            '${FlutterCaesiumFfi.nativeVersion}\n'
            'compress: ${result.inputSize} → ${result.outputSize} bytes\n'
            'target-size: ${targeted.outputSize} bytes\n'
            'convert to WebP: ${converted.outputSize} bytes';
      });
    } on Object catch (error) {
      setState(() => _status = error.toString());
    } finally {
      if (mounted) {
        setState(() => _running = false);
      }
    }
  }

  bool _isWebp(Uint8List bytes) {
    return bytes.length >= 12 &&
        bytes[0] == 0x52 &&
        bytes[1] == 0x49 &&
        bytes[2] == 0x46 &&
        bytes[3] == 0x46 &&
        bytes[8] == 0x57 &&
        bytes[9] == 0x45 &&
        bytes[10] == 0x42 &&
        bytes[11] == 0x50;
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: true, colorSchemeSeed: Colors.indigo),
      home: Scaffold(
        appBar: AppBar(title: const Text('flutter_caesium_ffi')),
        body: Center(
          child: Padding(
            padding: const EdgeInsets.all(24),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: <Widget>[
                Text(_status, textAlign: TextAlign.center),
                const SizedBox(height: 24),
                FilledButton(
                  onPressed: _running ? null : _compressSample,
                  child: const Text('Compress sample PNG'),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}