Flutter Sticker Maker

A cross-platform Flutter plugin to create stickers by removing backgrounds from images using iOS Vision/CoreImage and ONNX.

Features

  • iOS 17.0: Uses Vision and CoreImage with enhanced quality settings and edge smoothing
  • Android and iOS below 17.0: Uses ONNX models for background removal
  • Configurable border support with customizable color and width
  • Simple Dart API

Quality Enhancements

  • Image preprocessing: Automatic contrast and brightness enhancement
  • Edge smoothing: Advanced algorithms to create natural-looking edges
  • Noise reduction: Built-in filtering for cleaner results
  • High-resolution support: Maintains image quality for large stickers

Performance Optimizations

  • Native FFI Processing: High-performance C/C++ implementation for mask processing operations
  • SIMD Optimizations: ARM NEON (Android) and Accelerate Framework (iOS) for vectorized operations
  • Optimized Algorithms: Separable Gaussian blur (O(n) vs O(n²)) and efficient distance transforms
  • Memory Management: Memory pooling and zero-copy operations to reduce allocation overhead
  • Expected Speedup: 2-5x faster sticker creation with 30-50% less memory usage

The native FFI optimization automatically falls back to pure Dart implementation if the native library is unavailable, ensuring compatibility across all platforms.

Usage

alternatively, you can initialize the plugin with the following code:

FlutterStickerMaker.initialize();

and dispose it when done:

FlutterStickerMaker.dispose();

make a sticker from an image:

import 'package:flutter_sticker_maker/flutter_sticker_maker.dart';

// Basic usage
final sticker = await FlutterStickerMaker.makeSticker(imageBytes);

// With border customization
final stickerWithBorder = await FlutterStickerMaker.makeSticker(
  imageBytes,
  addBorder: true,
  borderColor: '#FF0000', // Red border
  borderWidth: 15.0,      // 15 pixel border width
);

Parameters

  • imageBytes: The input image as Uint8List (PNG/JPEG)
  • addBorder: Whether to add a border around the sticker (default: true)
  • borderColor: Hex color string for the border (default: '#FFFFFF')
  • borderWidth: Width of the border in pixels (default: 12.0)

Examples

Demo App Screenshots

example

See example/ for a full demo app.

Setup

  • iOS: Minimum iOS 15.5
  • Android: Minimum SDK 21

Permissions

Add to AndroidManifest.xml:

<uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" android:maxSdkVersion="32"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="28"/>
<uses-permission android:name="android.permission.CAMERA" />

Add to ios/Runner/Info.plist:

<key>NSPhotoLibraryUsageDescription</key>
<string>This app needs access to your photo library to pick images and save stickers.</string>
<key>NSCameraUsageDescription</key>
<string>This app needs camera access to take pictures for sticker creation.</string>
<key>NSPhotoLibraryAddUsageDescription</key>
<string>This app saves stickers to your photo library.</string>

Thanks

image_background_remover

Libraries

flutter_sticker_maker