image_native_watermark 0.0.4

High-performance native Android & iOS camera frame processing and watermarking (NV21/BGRA to JPEG, rotation, flipping, resizing, and text overlay).

image_native_watermark

A high-performance Flutter plugin for native camera frame processing and image file watermarking (rotation, scaling, text overlay, and JPEG compression) on Android and iOS.

Features

• ⚡ High Performance Native Processing: Executes the full image pipeline natively (Android Kotlin/Bitmap & iOS Swift/CoreGraphics) bypassing Dart thread overhead and Shorebird interpreter slowdowns.
• 📷 Camera Frame Processing: Converts raw camera stream bytes (NV21 / BGRA8888) directly into watermarked compressed JPEG images.
• 🖼️ Image File Watermarking: Watermark existing image files (e.g. from image_picker or file system) via ImageNativeWatermark.processImagePath.
• 📱 Orientation & Mirroring: Supports hardware rotation angle alignment and front camera horizontal mirroring.
• 📐 Dynamic Scaling & Compression: Custom target max width resizing and JPEG quality compression.
• ✍️ Text Overlay: Overlay custom text watermark timestamp or custom metadata directly onto the image.

Installation

Add image_native_watermark to your pubspec.yaml:

dependencies:
  image_native_watermark: 0.0.2

Or run:

flutter pub add image_native_watermark

Usage

1. Watermark Image File (e.g., ImagePicker)

import 'package:image_native_watermark/image_native_watermark.dart';

Future<String?> watermarkPickedImage(String inputPath, String outputPath) async {
  final String? result = await ImageNativeWatermark.processImagePath(
    imagePath: inputPath,
    watermarkText: "Location: -6.200000, 106.816666\nDate: 2026-07-23 11:00:00",
    outputPath: outputPath,
    quality: 85,
    targetMaxWidth: 1080,
  );

  return result;
}

2. Stream Frame Handling (Raw Camera Stream)

import 'package:flutter/services.dart';
import 'package:image_native_watermark/image_native_watermark.dart';

Future<String?> processCameraFrame(Uint8List frameBytes, int width, int height) async {
  final String? outputPath = await ImageNativeWatermark.processFrame(
    bytes: frameBytes,
    width: width,
    height: height,
    bytesPerRow: width * 4,
    rotationAngle: 90,
    isFrontCamera: true,
    watermarkText: "Location: -6.200000, 106.816666\nDate: 2026-07-23 11:00:00",
    quality: 85,
    targetMaxWidth: 1080,
    outputPath: "/path/to/output.jpg",
  );

  return outputPath;
}

Author

Andika Tri Prasetya

• Email: [e-mail]
• GitHub: github.com/andikatp

License

This project is licensed under the MIT License - see the LICENSE file for details.