Subject Lift Kit #

A Flutter plugin for extracting foreground objects from images using iOS Vision Framework's VNGenerateForegroundInstanceMaskRequest.

Features #

• 🎯 Extract foreground objects from images (people, animals, objects)
• 🖼️ Generate transparent background cutouts
• 📱 iOS 17.0+ support using Apple's Vision Framework

Example #

Requirements #

• iOS 17.0 or later
• Physical iOS device (simulator not supported)
• Flutter 3.3.0+

Installation #

Add this to your package's pubspec.yaml file:

dependencies:
  subject_lift_kit: ^0.0.1

Usage #

Basic Usage #

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

// Load your image as Uint8List
Uint8List imageBytes = await loadImageBytes();

try {
  // Extract foreground objects
  final result = await SubjectLiftKit.extractForeground(imageBytes);
  
  // Use the results
  if (result.cutoutImageBytes != null) {
    // Display the cutout image with transparent background
    Image.memory(result.cutoutImageBytes!);
  }
  
  if (result.maskImageBytes != null) {
    // Display the binary mask
    Image.memory(result.maskImageBytes!);
  }
} catch (e) {
  print('Error: $e');
}

Check Device Compatibility #

bool isSupported = await SubjectLiftKit.isSupported();
if (!isSupported) {
  print('Device does not support subject lifting');
}

Complete Example #

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

class SubjectLiftExample extends StatefulWidget {
  @override
  _SubjectLiftExampleState createState() => _SubjectLiftExampleState();
}

class _SubjectLiftExampleState extends State<SubjectLiftExample> {
  SegmentationResult? _result;
  bool _isProcessing = false;

  Future<void> _pickAndProcessImage() async {
    final picker = ImagePicker();
    final image = await picker.pickImage(source: ImageSource.gallery);
    
    if (image == null) return;

    setState(() {
      _isProcessing = true;
    });

    try {
      final bytes = await image.readAsBytes();
      final result = await SubjectLiftKit.extractForeground(bytes);
      
      setState(() {
        _result = result;
      });
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Error: $e')),
      );
    } finally {
      setState(() {
        _isProcessing = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Subject Lift Kit')),
      body: Column(
        children: [
          ElevatedButton(
            onPressed: _isProcessing ? null : _pickAndProcessImage,
            child: _isProcessing
                ? CircularProgressIndicator()
                : Text('Pick & Process Image'),
          ),
          if (_result?.cutoutImageBytes != null)
            Expanded(
              child: Image.memory(_result!.cutoutImageBytes!),
            ),
        ],
      ),
    );
  }
}

API Reference #

SubjectLiftKit #

Methods

• static Future<SegmentationResult> extractForeground(Uint8List imageBytes)

  • Extracts foreground objects from the given image
  • Returns a SegmentationResult with mask and cutout images
  • Throws SubjectLiftException on error

• static Future<bool> isSupported()

  • Checks if the current device supports subject lifting
  • Returns true for iOS 17.0+ devices

SegmentationResult #

• Uint8List? maskImageBytes - Binary mask image as PNG data
• Uint8List? cutoutImageBytes - Cutout image with transparent background as PNG data
• String? error - Error message if operation failed

SubjectLiftException #

Exception thrown when subject lifting operations fail.

Limitations #

• iOS Only: Currently only supports iOS platform
• iOS 17.0+: Requires iOS 17.0 or later
• Physical Device: Does not work on iOS Simulator

Contributing #

Contributions are welcome! Please feel free to submit a Pull Request.

License #

This project is licensed under the BSD 3-Clause License - see the LICENSE file for details.

Credits #

Built using Apple's Vision Framework and the VNGenerateForegroundInstanceMaskRequest API.