pixo_flutter 1.0.1

Flutter/Dart bindings for the pixo Rust image compression library.

pixo_flutter

Flutter plugin package that wraps the Rust pixo image compression library via Dart FFI.

This package exposes a small, hexagonally-structured API to encode raw pixel buffers as PNG or JPEG using pixo's high-performance encoders.

Architecture

• lib/src/domain/
  • options.dart — domain models for PNG/JPEG options and encoded images.
• lib/src/application/
  • pixo_service.dart — application service façade used by callers.
• lib/src/infrastructure/
  • backend_ffi.dart — native bindings to the Rust pixo library via FFI.
  • backend_web_stub.dart — placeholder for a future Flutter web backend.

The public entry point is PixoService plus the domain option types:

import 'package:pixo_flutter/pixo_flutter.dart';

Building the native library

This package expects a native pixo library built with the ffi feature.

From the pixo_flutter root, build the native library:

dart run tool/build_native.dart

This calls:

cargo build --release --features ffi

Resulting artifacts (paths from repo root):

• macOS: rust/target/release/libpixo.dylib
• iOS: build/link into the Xcode target (Dart uses DynamicLibrary.process())
• Android: rust/target/release/libpixo.so
• Linux: rust/target/release/libpixo.so
• Windows: rust/target/release/pixo.dll

You are responsible for copying these into your Flutter app or plugin according to Flutter's platform conventions (e.g. android/app/src/main/jniLibs, ios/Runner, macos/Runner, etc.).

Usage

import 'dart:typed_data';
import 'package:pixo_flutter/pixo_flutter.dart';

Future<void> example() async {
  final service = PixoService();

  // 1x1 red RGBA pixel
  final pngPixels = Uint8List.fromList([255, 0, 0, 255]);

  final pngOptions = PixoPngOptions(
    width: 1,
    height: 1,
    colorType: 3, // Rgba
    preset: 1,    // balanced
    lossless: true,
  );

  final png = await service.encodePngPixels(pngPixels, pngOptions);

  // JPEG: RGB only (strip alpha yourself if needed)
  final jpegPixels = Uint8List.fromList([255, 0, 0]);

  final jpegOptions = PixoJpegOptions(
    width: 1,
    height: 1,
    colorType: 2,  // Rgb
    quality: 85,
    preset: 1,
    subsampling420: true,
  );

  final jpeg = await service.encodeJpegPixels(jpegPixels, jpegOptions);

  // png.bytes / jpeg.bytes now hold compressed image data.
}

Testing

The test/compress_test.dart file contains basic integration tests which:

• Encode a 1x1 PNG and assert the standard PNG signature bytes.
• Encode a 1x1 JPEG and assert the JPEG SOI marker.
• Decode test/test.png and encode it to PNG and JPEG, asserting signatures.

To run tests:

export PIXO_LIBRARY_PATH="$PWD/rust/target/release/libpixo.dylib"
flutter test

To run the integration test on a device/emulator:

export PIXO_LIBRARY_PATH="$PWD/rust/target/release/libpixo.dylib"
flutter test integration_test

Example app

An example app is available under example/.

Web support

Currently the Flutter web backend is a stub and will throw UnsupportedError. Future work can integrate the existing pixo WASM build via JS interop.

Built with love by kudah ndhlovu for the Zimbabwe fintech ecosystem