heic2png 0.0.2

A Flutter plugin that converts HEIC/HEIF images to PNG using native platform APIs (iOS, Android, macOS, Windows, Linux).

heic2png

A Flutter plugin that converts HEIC/HEIF images to PNG using native platform APIs. Fully offline, no third-party services -- just lossless conversion on-device.

Features

• Lossless HEIC/HEIF to PNG conversion
• Convert to file or to in-memory bytes
• Configurable PNG compression level (0-9)
• Metadata preservation (ICC color profiles, EXIF data)
• Cross-platform: iOS, Android, macOS, Windows, Linux
• Uses native APIs on each platform for maximum performance:
  • iOS / macOS: CoreGraphics / ImageIO
  • Android: BitmapFactory + ExifInterface
  • Windows: Windows Imaging Component (WIC)
  • Linux: libheif + libpng

Installation

dependencies:
  heic2png: ^0.0.1

iOS

No additional setup needed (iOS 12.0+).

Android

Requires Android 9 (API 28) or later (native HEIF decoder support).

Set minSdk = 28 in your app's android/app/build.gradle.kts:

android {
    defaultConfig {
        minSdk = 28
    }
}

macOS

No additional setup needed (macOS 10.13+).

Windows

Requires Windows 10 version 1809 or later. The HEIF Image Extensions from the Microsoft Store may be required on Windows 10; Windows 11 bundles the codec.

Linux

Install the required native libraries:

sudo apt install libheif-dev libpng-dev

Usage

Convert to a file

import 'package:heic2png/heic2png.dart';

final success = await Heic2png.convert('/path/to/input.heic', '/path/to/output.png');
if (success) {
  print('Converted successfully!');
}

Convert to bytes

final bytes = await Heic2png.convertToBytes('/path/to/input.heic');
if (bytes != null) {
  // Use the PNG bytes (e.g. display with Image.memory)
}

Compression level

Control how much effort is spent compressing the output PNG. 0 is fastest (largest file), 9 is slowest (smallest file). Default is 6.

// Fastest conversion, larger file
await Heic2png.convert(input, output, compressionLevel: 0);

// Maximum compression, slower
await Heic2png.convert(input, output, compressionLevel: 9);

// Also works with convertToBytes
final bytes = await Heic2png.convertToBytes(input, compressionLevel: 9);

Metadata preservation

By default, ICC color profiles and EXIF data (camera info, GPS, orientation, date/time) are preserved from the source HEIC file. Set preserveMetadata: false to strip all metadata:

// Strip all metadata (ICC profile, EXIF, GPS, etc.)
await Heic2png.convert(input, output, preserveMetadata: false);

// Combine options
final bytes = await Heic2png.convertToBytes(
  input,
  compressionLevel: 0,
  preserveMetadata: false,
);

API

Method	Description
Heic2png.convert(inputPath, outputPath, {compressionLevel, preserveMetadata})	Converts a HEIC file to PNG and writes it to outputPath. Returns true on success.
Heic2png.convertToBytes(inputPath, {compressionLevel, preserveMetadata})	Converts a HEIC file to PNG and returns the bytes as Uint8List. Returns null on failure.

Parameters

Parameter	Type	Default	Description
inputPath	String	required	Path to the source HEIC/HEIF file.
outputPath	String	required	Path for the output PNG file (convert only).
compressionLevel	int	6	PNG compression effort, 0 (fastest) to 9 (smallest).
preserveMetadata	bool	true	Preserve ICC color profiles and EXIF data from the source.

Platform notes

Compression level

Platform	Behavior
Linux	Maps directly to zlib compression level (0-9). Full granularity.
iOS / macOS	Controls PNG row filter strategy: 0 = no filter (fastest), 1-9 = adaptive filter (best compression). Levels 1-9 produce the same output.
Windows	Same as iOS/macOS (WIC FilterOption).
Android	Accepted but has no effect. Android's Bitmap.compress(PNG) uses a fixed internal compression level.

Metadata preservation

Metadata	iOS	Android	macOS	Windows	Linux
ICC color profiles	Yes	No	Yes	Yes	Yes
EXIF data	Yes	Yes	Yes	No	Yes (libpng >= 1.6.32)

• iOS / macOS preserve all metadata (EXIF, ICC, GPS, TIFF tags, XMP) automatically via CGImageDestinationAddImageFromSource.
• Android transfers EXIF tags (camera info, GPS, orientation, date/time) via AndroidX ExifInterface. ICC color profile transfer is not supported -- colors are converted to sRGB during encoding.
• Windows preserves ICC color profiles via WIC color contexts. EXIF transfer across container formats is not supported.
• Linux preserves ICC profiles via png_set_iCCP and EXIF via png_set_eXIf_1 (requires libpng 1.6.32+). On older libpng versions, EXIF is silently skipped.

Example

See the example app for a complete working demo.

License

MIT -- see LICENSE for details.