HEIC to PNG / JPG / WebP Converter #

A Flutter package to convert HEIC images to PNG, JPG, or WebP on mobile, web, and desktop.

Features #

• Convert HEIC/HEIF images to JPG, PNG, or WebP
• Web, iOS, Android, macOS, Windows, Linux support
• Resize by maxWidth, maxHeight, or both (aspect-ratio-preserving contain mode)
• Adjustable JPG / WebP quality (0–100)
• isHeic() — fast magic-byte check, no decode required
• getImageInfo() — read dimensions without full conversion
• convertBatch() — convert multiple files concurrently
• convertFile() — file-path API (mobile / desktop)
• Custom exception types for fine-grained error handling
• Isolate-based processing keeps the UI thread free

Platform support #

* Desktop and WebP on mobile use the Dart image package fallback (HEIC support may be limited; WebP output falls back to PNG on mobile).

Installation #

dependencies:
  heic_to_png_jpg: ^0.1.0

flutter pub get

No changes to web/index.html are needed — the package loads libheif-js automatically.

Usage #

Basic conversion #

import 'package:heic_to_png_jpg/heic_to_png_jpg.dart';

final Uint8List heicData = ...; // from file, network, etc.

// Convert to JPG
final jpg = await HeicConverter.convertToJPG(heicData: heicData, quality: 85);

// Convert to PNG
final png = await HeicConverter.convertToPNG(heicData: heicData);

// Convert to WebP (web: native; mobile: falls back to PNG)
final webp = await HeicConverter.convertToWebP(heicData: heicData, quality: 85);

// Generic — choose format at runtime
final output = await HeicConverter.convertToImage(
  heicData: heicData,
  format: ImageFormat.jpg,
  quality: 85,
  maxWidth: 1280,
  maxHeight: 720, // NEW: contain-mode when both are set
);

Resize #

// Scale to fit within 800 × 600, preserving aspect ratio
final resized = await HeicConverter.convertToJPG(
  heicData: heicData,
  maxWidth: 800,
  maxHeight: 600,
);

// Constrain only width
final byWidth = await HeicConverter.convertToPNG(
  heicData: heicData,
  maxWidth: 1024,
);

Check if a file is HEIC #

// Fast — checks magic bytes only, no decoding
if (HeicConverter.isHeic(bytes)) {
  // safe to convert
}

Read image dimensions #

final info = await HeicConverter.getImageInfo(heicData);
print('${info.width} × ${info.height}');

Batch conversion #

final tasks = [
  HeicConversionTask(heicData: data1, format: ImageFormat.jpg, quality: 85),
  HeicConversionTask(heicData: data2, format: ImageFormat.png, maxWidth: 800),
];

final results = await HeicConverter.convertBatch(
  tasks: tasks,
  concurrency: 3, // max simultaneous conversions
);

File-path API (mobile / desktop only) #

final outputPath = await HeicConverter.convertFile(
  inputPath: '/path/to/photo.heic',
  format: ImageFormat.jpg,
  quality: 85,
  maxWidth: 1280,
);

Error handling #

import 'package:heic_to_png_jpg/heic_to_png_jpg.dart';

try {
  final jpg = await HeicConverter.convertToJPG(heicData: data);
} on InvalidHeicDataException catch (e) {
  // Bad input (wrong format, invalid quality value)
  print(e.message);
} on ConversionFailedException catch (e) {
  // Encoding / decoding error
  print('${e.message} — caused by: ${e.cause}');
} on PlatformNotSupportedException catch (e) {
  // Feature not available on this platform
  print(e.message);
} on HeicConversionException catch (e) {
  // Any other conversion error
  print(e.message);
}

Custom libheif-js URL (web) #

final png = await HeicConverter.convertToPNG(
  heicData: heicData,
  libheifJsUrl: 'https://cdn.jsdelivr.net/npm/libheif-js@1.19.8/libheif-wasm/libheif-bundle.js',
);

Migration from 0.0.x #

The core API (convertToJPG, convertToPNG, convertToImage, maxWidth, quality, libheifJsUrl) is fully backward compatible.

Notes #

• Mobile (iOS / Android): Uses heif_converter for native decoding, falls back to the Dart image package if it fails.
• Web: Uses libheif-js (WebAssembly); auto-loaded from jsDelivr CDN.
• Desktop: Uses the Dart image package fallback (HEIC support may be limited).
• WebP on mobile: The image package has no WebP encoder, so WebP output falls back to PNG. Web uses the browser's native canvas encoder.

Issues and Contributions #

Please file issues, bugs, or feature requests on GitHub.

License #

MIT — see LICENSE.

About the Author #

Ibrahim El Mourchidi

Flutter & Firebase Developer • Cairo, Egypt

• Top-rated Flutter freelancer (100% Job Success on Upwork)
• Built 20+ production apps with real-time & payment features
• Passionate about clean architecture, compliance, and UX

👥 Contributors

We appreciate all contributions to this project!