h3_ffi_plus 1.0.0+v4.2.1

Dart FFI implementation of the abstract H3 interface from h3_common_plus. Not intended for direct use.

h3_ffi_plus

h3_ffi_plus is a low-level Dart library that provides H3 bindings for native (non-web) platforms using Dart's FFI and ffigen.

⚠️ This package is not intended for direct use. Instead, use one of the higher-level packages:

• h3_dart_plus — For general Dart apps. Requires manual linking of the native H3 C library (libh3.so, h3.dll, etc.).
• h3_flutter_plus — For Flutter apps on Android, desktop, and web. Native linking is handled automatically by the build system.

About This Package

This package provides one of the internal implementations of the abstract H3 interface defined in h3_common_plus. It leverages native C bindings through Dart FFI to provide a performant, native-backed H3 API.

Although it can technically be used directly by instantiating an H3FfiFactory and loading a dynamic library, this is not recommended unless you know what you're doing. You’ll need to handle:

• Dynamic library loading
• FFI-native data types and memory management
• Potential cross-platform inconsistencies

Example (Direct Use)

import 'package:h3_ffi_plus/h3_ffi_plus.dart';

final h3 = const H3FfiFactory().byPath('path/to/libh3.so');
final indexes = h3.polygonToCells(
  resolution: 6,
  coordinates: [
    LatLng(lat:37.775, lng:-122.418),
    LatLng(lat:37.776, lng:-122.419),
    LatLng(lat:37.777, lng:-122.417),
  ],
);

History & Migration

This library is a modernized and rewritten successor to the original h3_ffi package created by festelo, which was based on H3 v3.7.2.

The current implementation supports H3 v4.2.1 and forms part of a complete rework of the Dart/Flutter H3 bindings ecosystem, including:

• Migration from H3 v3 to v4
• Inclusion of vertex mode functions and experimental functions
• Check the Changelogs for more details

This package exists primarily to support other public-facing packages, not for end-user consumption.

License

This project is licensed under the Apache 2.0 License.