suryatmodulus / blurhash-dart

A pure dart implementation of blurhash

BlurHash Dart

A pure dart implementation of BlurHash without any external dependencies (except for running tests) for maximum flexibility. Supports encoding and decoding. See 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

Decoding a BlurHash returns a raw array of pixels in RGBA32 format. You must convert the data to an image yourself. For this example we use the bitmap package to convert the pixel array to an bitmap, then to an ui.Image.

import 'package:blurhash_dart/blurhash_dart.dart';
import 'package:bitmap/bitmap.dart';

import 'dart:ui' as ui; // for displaying the image
//..

String blurHash = "LEHV6nWB2yk8pyo0adR*.7kCMdnj";
Uint8List pixels = decodeBlurHash(blurHash, 35, 20);

Bitmap bitmap = Bitmap.fromHeadless(35, 20, pixels);
ui.Image image = await bitmap.buildImage();
//..

Encoding a BlurHash

For demo purposes we assume to have the popular image package installed, which decodes image files. The blurhash-dart API expects raw pixels in RGBA32 format for maximum flexibility.

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

Uint8List fileData = File("some_image.png").readAsBytesSync();
img.Image image = img.decodeImage(fileData.toList());

final blurHash = encodeBlurHash(
  image.getBytes(format: Format.rgba),
  image.width,
  image.height,
);

print("$blurHash");