M3E Color Scheme

A Flutter package providing AOSP-aligned native color scheme generation and a robust fixup for the dynamic_color package in Flutter. It correctly populates the newer tone-based Material 3 surface and container roles, guarantees accessibility-compliant on*Container contrast mappings (resolving to Tone 30/Tone 90 instead of dull system Tone 10), and enables advanced dynamic variants (such as Expressive, Vibrant, Fidelity, Fruit Salad) with real-time contrast control.

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🎮 Interactive Demo

You can try out the package UI demo here: m3e_core demo

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🚀 Features

• dynamic_color Fixup — Correctly overrides and populates missing or incorrect OS-provided dynamic color roles (e.g., populating new surface container roles).
• AOSP-Aligned Contrasts — Ensures container foreground text/icons (onPrimaryContainer, etc.) use vibrant, high-readability Tone 30 (light mode) / Tone 90 (dark mode) as defined by AOSP ColorSpec2026, bypassing dull system Tone 10 rendering.
• 8 Color Variants — Generate custom tonal palettes dynamically using tonalSpot, vibrant, fidelity, expressive, monochrome, neutral, rainbow, and fruitSalad.
• Contrast-Level Control — Adjust dynamic scheme contrast levels on the fly (from -1.0 to 1.0) with automatic accessibility compliance.
• Automatic Brightness Adaptation — Fluidly generates matching light and dark themes using uniform HCT color specifications.

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📦 Installation

dependencies:
  m3e_color_scheme: ^0.0.1

import 'package:m3e_color_scheme/m3e_color_scheme.dart';

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🧩 Quick Start

1. Standalone Replacement for ColorScheme.fromSeed

To generate color schemes with advanced variants and contrast levels inside the Dart runtime, replace your default ColorScheme.fromSeed constructor:

MaterialApp(
  theme: ThemeData(
    colorScheme: M3EColorScheme.light(
      seedColor: Colors.deepPurple,
      variant: M3EColorVariant.expressive, // Instantly unlocks expressive hue-rotations
      contrastLevel: 0.0, // Adjust from -1.0 to 1.0
    ),
    useMaterial3: true,
  ),
  darkTheme: ThemeData(
    colorScheme: M3EColorScheme.dark(
      seedColor: Colors.deepPurple,
      variant: M3EColorVariant.expressive,
      contrastLevel: 0.0,
    ),
    useMaterial3: true,
  ),
  home: const HomeScreen(),
);

2. Fixup Mapping for dynamic_color Package (Android 12+)

To fix missing surface containers or dull Tone 10 container contrast roles provided by the Android OS, wrap your MaterialApp with DynamicColorBuilder and feed the system scheme to M3EColorScheme:

DynamicColorBuilder(
  builder: (lightDynamic, darkDynamic) {
    final lightScheme = M3EColorScheme.light(
      seedColor: lightDynamic?.primary ?? Colors.deepPurple,
      systemColorScheme: lightDynamic, // Intercepts and corrects system mappings
      variant: M3EColorVariant.tonalSpot,
    );
    
    final darkScheme = M3EColorScheme.dark(
      seedColor: darkDynamic?.primary ?? Colors.deepPurple,
      systemColorScheme: darkDynamic, // Intercepts and corrects system mappings
      variant: M3EColorVariant.tonalSpot,
    );

    return MaterialApp(
      theme: ThemeData(
        colorScheme: lightScheme,
        useMaterial3: true,
      ),
      darkTheme: ThemeData(
        colorScheme: darkScheme,
        useMaterial3: true,
      ),
      home: const HomeScreen(),
    );
  },
);

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📖 Detailed API Guide

1. M3EColorScheme.light & M3EColorScheme.dark

Constructors to generate light or dark ColorScheme palettes with AOSP modifications:

Parameter	Type	Default	Description
seedColor	Color	(Required)	The source color for the HCT palette.
contrastLevel	double	0.0	Contrast adjustments between -1.0 (low) and 1.0 (high).
variant	M3EColorVariant	M3EColorVariant.tonalSpot	The dynamic scheme generation logic to apply.
systemColorScheme	ColorScheme?	null	Android system-provided scheme. When supplied, it copies and overrides the system values with corrected container/surface roles.

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2. M3EColorVariant

Tonal specification presets for dynamic palette generation:

Variant	Description
tonalSpot	Standard Material 3 dynamic color scheme (pastel, balanced).
vibrant	Emphasizes secondary and tertiary vibrancies for rich highlights.
fidelity	Keeps generated tones highly faithful to the seed color's exact chroma.
expressive	Employs bold dynamic hue-rotations (e.g. vivid magenta accents on a purple seed).
monochrome	Generates a pure greyscale palette with solid black/white tones.
neutral	Muted, near-neutral tones with extremely low chroma.
rainbow	Rotates hues through a distinct rainbow spectrum.
fruitSalad	Organic, fruit-inspired palettes with shifted tertiary colors.

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🐞 Found a bug? or ✨ You have a Feature Request?

Feel free to open an Issue or Contribute to the project via the main repository.

Hope You Love It!

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Radhe Radhe 🙏