palette_generator_plus 1.0.0

Extract prominent colors from images. A maintained palette_generator successor.

palette_generator_plus

The maintained, modernized successor to Flutter's discontinued palette_generator package (officially discontinued in flutter/flutter#162963, which invited a sustainable community fork).

palette_generator_plus extracts the prominent colors — dominant, vibrant, muted, and their light/dark variants — from any image, and adds the modern capabilities the original never had:

• 🧵 Isolate-based extraction by default, with a transparent main-thread fallback on the web.
• 🎨 Pluggable quantizers — a material_color_utilities-backed CelebiQuantizer (default) and the original median-cut LegacyQuantizer for byte-identical legacy output.
• 🧩 One-call Material 3 bridge — turn any image into a complete ColorScheme.
• ♿ WCAG-accessible text colors — exact WCAG 2.1 contrast math and helpers.
• 🔁 Drop-in compatible — the entire original public API is preserved.

Migrating from palette_generator

Migration is a single import-line change. Every existing class, method, parameter, and getter keeps the same name and a compatible signature:

- import 'package:palette_generator/palette_generator.dart';
+ import 'package:palette_generator_plus/palette_generator_plus.dart';

Your existing code compiles and runs unchanged. Everything else this package adds is strictly additive.

Note: colors are extracted with the modern CelebiQuantizer by default. For output that is byte-identical to palette_generator 0.3.3+7, pass quantizer: const LegacyQuantizer() to any from* constructor.

Why this package?

Capability	palette_generator_plus	palette_generator (discontinued)	ColorScheme.fromImageProvider
Maintained	✅	❌	✅
Raw swatches + population counts	✅	✅	❌
Named targets (vibrant / muted / …)	✅	✅	❌
Drop-in API of palette_generator	✅	—	❌
Isolate extraction (off the UI thread)	✅	❌	❌
Pluggable quantizer	✅	❌	❌
Material 3 ColorScheme in one call	✅	❌	✅
WCAG contrast helpers	✅	❌	❌
Modern color API, zero deprecations	✅	❌	✅
All 6 platforms	✅	✅	✅

Quickstart

Add the dependency:

dependencies:
  palette_generator_plus: ^1.0.0

Basic extraction

import 'package:palette_generator_plus/palette_generator_plus.dart';

final PaletteGenerator palette = await PaletteGenerator.fromImageProvider(
  const AssetImage('assets/landscape.png'),
);

final Color? dominant = palette.dominantColor?.color;
for (final PaletteColor swatch in palette.paletteColors) {
  print('${swatch.color} occurs ${swatch.population} times');
}

Named swatches

final Color? vibrant = palette.vibrantColor?.color;
final Color? darkMuted = palette.darkMutedColor?.color;
final Color? lightVibrant = palette.lightVibrantColor?.color;

Material 3 ColorScheme in one call

final ColorScheme scheme = palette.toColorScheme(
  brightness: Brightness.dark,
);
final ThemeData theme = ThemeData.from(colorScheme: scheme);

// Or just grab the seed for ThemeData(colorSchemeSeed: ...):
final Color seed = palette.seedColor;

WCAG-accessible text colors

// A fully-opaque black or white that reads accessibly on the swatch:
final Color textColor = palette.dominantColor!.accessibleOnColor(
  level: WcagLevel.aaa,
);

// Or use the standalone helpers on any color:
final double ratio = contrastRatio(Colors.black, Colors.white); // 21.0
final Color onSurface = wcagTextColor(scheme.surface);

Choose the quantizer / run on the main thread

final PaletteGenerator legacy = await PaletteGenerator.fromImageProvider(
  const AssetImage('assets/landscape.png'),
  quantizer: const LegacyQuantizer(), // byte-identical to the original
  runInIsolate: false,                // opt out of the background isolate
);

See the example/ directory for a complete app (it also runs as a live web demo via flutter build web).

API overview

Symbol	Description
PaletteGenerator.fromImage / .fromImageProvider / .fromByteData	Extract a palette from an image.
PaletteColor	A swatch: color, population, titleTextColor, bodyTextColor, accessibleOnColor.
PaletteTarget	A tunable target in HSL space; predefined vibrant, muted, etc.
PaletteFilter / avoidRedBlackWhitePaletteFilter	Filter which colors are eligible.
Quantizer / CelebiQuantizer / LegacyQuantizer	Pluggable color-reduction algorithms.
PaletteGenerator.seedColor / .toColorScheme()	Material 3 bridge.
contrastRatio / wcagTextColor / WcagLevel	WCAG 2.1 accessibility helpers.
EncodedImage	Raw RGBA pixel data for fromByteData.

Compatibility

Pure Dart/Flutter — no platform channels or native code. Runs on Android, iOS, web, Windows, macOS and Linux. On the web, where dart:isolate is unavailable, runInIsolate transparently falls back to the main thread; the result is identical regardless of where it runs.

Acknowledgements

This package is a community-maintained fork and successor of the discontinued palette_generator package, last published as palette_generator 0.3.3+7, originally created by The Flutter Authors / Google and distributed under the BSD-3-Clause license.

Files derived from the original retain their original copyright headers; see LICENSE and NOTICE. The discontinuation and community fork invitation are tracked in flutter/flutter#162960 and flutter/flutter#162963.

Color science is powered by material_color_utilities, the same library behind Flutter's dynamic color and Android's Material You.

Contributing

Issues and pull requests are welcome at https://github.com/KEREM-BAS/palette_generator_plus. Please run dart format ., flutter analyze and flutter test before submitting.

License

BSD-3-Clause. See LICENSE.