blurhash_dart

Package Overview

Package selection guidance compiled from public package information, community data, and project usage.

BlurHash Dart is a pure Dart implementation of the BlurHash algorithm, enabling efficient generation and decoding of compact image placeholders. It provides encoder and decoder functionality along with useful utility extensions for seamless integration into Flutter applications. Ideal for displaying low-bandwidth previews of images during loading, it supports all major platforms including Android, iOS, Web, macOS, Windows, and Linux. The package is lightweight and designed for performance without external dependencies.

Use cases

Generating image placeholders during loading
Creating low-resolution previews for large images
Improving perceived app performance with placeholder visuals
Integrating blur effects in image thumbnails
Optimizing image loading in network-heavy apps

Key features

Pure Dart implementation
Encoder and decoder included
Utility extensions for ease of use
Cross-platform compatibility
Lightweight and fast
No native dependencies

Suitable for

Flutter developers needing image placeholders
Apps with slow or variable network conditions
Performance-focused UI implementations
Developers avoiding platform-specific code
Projects requiring minimal third-party libraries

Considerations

Not suitable for high-fidelity image representation
Requires understanding of BlurHash concept
Limited to placeholder use cases
May not support advanced image processing features
Best used as a visual enhancement, not a replacement for actual images

Original README

Original README snapshot from the linked source repository. Visit the repository for the latest content.

BlurHash Dart

A pure dart implementation of BlurHash. Supports both encoding and decoding. Runs on every supported Dart platform. See the BlurHash website or GitHub repository for more information.

The encoder of this dart implementation produces slightly different hashes than the TypeScript implementation but matches the official C and Python implementation. In practice this should not be relevant.

Basic usage

Decoding a BlurHash

import 'package:blurhash_dart/blurhash_dart.dart';
import 'package:image/image.dart' as img;

const hash = 'LEHV6nWB2yk8pyo0adR*.7kCMdnj';
BlurHash blurHash = BlurHash.decode(hash);
img.Image image = blurHash.toImage(35, 20);

// Display image...

Note: Usage with Flutter

Flutter does not expect raw bytes for its Image.memory widget, but fully encoded images with their corresponding headers (e.g. bitmap, jpg, png). The easiest way to accomplish this, is to use, for example, encodeJpg from package:image:

Widget build(BuildContext context) {
  final image = BlurHash.decode('LEHV6nWB2yk8pyo0adR*.7kCMdnj').toImage(35, 20);
  return Image.memory(Uint8List.fromList(encodeJpg(image)));
}

It is recommended to cache the resulting image in a stateful widget, such that it does not need to be recomputed on every build call.

Encoding an Image

import 'dart:io';

import 'package:blurhash_dart/blurhash_dart.dart';
import 'package:image/image.dart' as img;

final data = File('path/to/image.png').readAsBytesSync();
final image = img.decodeImage(data.toList());
final blurHash = BlurHash.encode(image!, numCompX: 4, numCompY: 3);

print(blurHash.hash);

Extension Methods

Additional extension methods to compute, for example color averages, are available when importing package:blurhash_dart/blurhash_extensions.dart. See example for basic usage.