samples/material_3_demo/lib/color_palettes_screen.dart

// Copyright 2021 The Flutter team. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:url_launcher/url_launcher.dart';

const Widget divider = SizedBox(height: 10);

// If screen content width is greater or equal to this value, the light and dark
// color schemes will be displayed in a column. Otherwise, they will
// be displayed in a row.
const double narrowScreenWidthThreshold = 400;

class ColorPalettesScreen extends StatelessWidget {
  const ColorPalettesScreen({super.key});

  @override
  Widget build(BuildContext context) {
    Color selectedColor = Theme.of(context).primaryColor;
    ThemeData lightTheme = ThemeData(
      colorSchemeSeed: selectedColor,
      brightness: Brightness.light,
    );
    ThemeData darkTheme = ThemeData(
      colorSchemeSeed: selectedColor,
      brightness: Brightness.dark,
    );

    Widget schemeLabel(String brightness) {
      return Padding(
        padding: const EdgeInsets.symmetric(vertical: 15),
        child: Text(
          brightness,
          style: const TextStyle(fontWeight: FontWeight.bold),
        ),
      );
    }

    Widget schemeView(ThemeData theme) {
      return Padding(
        padding: const EdgeInsets.symmetric(horizontal: 15),
        child: ColorSchemeView(
          colorScheme: theme.colorScheme,
        ),
      );
    }

    Widget dynamicColorNotice() => RichText(
          textAlign: TextAlign.center,
          text: TextSpan(
            style: Theme.of(context).textTheme.bodySmall,
            children: [
              const TextSpan(
                  text: 'To create color schemes based on a '
                      'platform\'s implementation of dynamic color, '
                      'use the '),
              TextSpan(
                text: 'dynamic_color',
                style: const TextStyle(decoration: TextDecoration.underline),
                recognizer: TapGestureRecognizer()
                  ..onTap = () async {
                    final url = Uri.parse(
                      'https://pub.dev/packages/dynamic_color',
                    );
                    if (!await launchUrl(url)) {
                      throw Exception('Could not launch $url');
                    }
                  },
              ),
              const TextSpan(text: ' package.'),
            ],
          ),
        );

    return Expanded(
      child: LayoutBuilder(builder: (context, constraints) {
        if (constraints.maxWidth < narrowScreenWidthThreshold) {
          return SingleChildScrollView(
            child: Column(
              children: [
                dynamicColorNotice(),
                divider,
                schemeLabel('Light ColorScheme'),
                schemeView(lightTheme),
                divider,
                divider,
                schemeLabel('Dark ColorScheme'),
                schemeView(darkTheme),
              ],
            ),
          );
        } else {
          return SingleChildScrollView(
            child: Padding(
              padding: const EdgeInsets.only(top: 5),
              child: Column(
                children: [
                  dynamicColorNotice(),
                  Row(
                    children: [
                      Expanded(
                        child: Column(
                          children: [
                            schemeLabel('Light ColorScheme'),
                            schemeView(lightTheme),
                          ],
                        ),
                      ),
                      Expanded(
                        child: Column(
                          children: [
                            schemeLabel('Dark ColorScheme'),
                            schemeView(darkTheme),
                          ],
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ),
          );
        }
      }),
    );
  }
}

class ColorSchemeView extends StatelessWidget {
  const ColorSchemeView({super.key, required this.colorScheme});

  final ColorScheme colorScheme;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        ColorGroup(
          children: [
            ColorChip(
              label: 'primary',
              color: colorScheme.primary,
              onColor: colorScheme.onPrimary,
            ),
            ColorChip(
              label: 'onPrimary',
              color: colorScheme.onPrimary,
              onColor: colorScheme.primary,
            ),
            ColorChip(
              label: 'primaryContainer',
              color: colorScheme.primaryContainer,
              onColor: colorScheme.onPrimaryContainer,
            ),
            ColorChip(
              label: 'onPrimaryContainer',
              color: colorScheme.onPrimaryContainer,
              onColor: colorScheme.primaryContainer,
            ),
          ],
        ),
        divider,
        ColorGroup(
          children: [
            ColorChip(
              label: 'secondary',
              color: colorScheme.secondary,
              onColor: colorScheme.onSecondary,
            ),
            ColorChip(
              label: 'onSecondary',
              color: colorScheme.onSecondary,
              onColor: colorScheme.secondary,
            ),
            ColorChip(
              label: 'secondaryContainer',
              color: colorScheme.secondaryContainer,
              onColor: colorScheme.onSecondaryContainer,
            ),
            ColorChip(
              label: 'onSecondaryContainer',
              color: colorScheme.onSecondaryContainer,
              onColor: colorScheme.secondaryContainer,
            ),
          ],
        ),
        divider,
        ColorGroup(
          children: [
            ColorChip(
              label: 'tertiary',
              color: colorScheme.tertiary,
              onColor: colorScheme.onTertiary,
            ),
            ColorChip(
              label: 'onTertiary',
              color: colorScheme.onTertiary,
              onColor: colorScheme.tertiary,
            ),
            ColorChip(
              label: 'tertiaryContainer',
              color: colorScheme.tertiaryContainer,
              onColor: colorScheme.onTertiaryContainer,
            ),
            ColorChip(
              label: 'onTertiaryContainer',
              color: colorScheme.onTertiaryContainer,
              onColor: colorScheme.tertiaryContainer,
            ),
          ],
        ),
        divider,
        ColorGroup(
          children: [
            ColorChip(
              label: 'error',
              color: colorScheme.error,
              onColor: colorScheme.onError,
            ),
            ColorChip(
              label: 'onError',
              color: colorScheme.onError,
              onColor: colorScheme.error,
            ),
            ColorChip(
              label: 'errorContainer',
              color: colorScheme.errorContainer,
              onColor: colorScheme.onErrorContainer,
            ),
            ColorChip(
              label: 'onErrorContainer',
              color: colorScheme.onErrorContainer,
              onColor: colorScheme.errorContainer,
            ),
          ],
        ),
        divider,
        ColorGroup(
          children: [
            ColorChip(
              label: 'surface',
              color: colorScheme.surface,
              onColor: colorScheme.onSurface,
            ),
            ColorChip(
              label: 'onSurface',
              color: colorScheme.onSurface,
              onColor: colorScheme.surface,
            ),
            ColorChip(
              label: 'surfaceVariant',
              color: colorScheme.surfaceVariant,
              onColor: colorScheme.onSurfaceVariant,
            ),
            ColorChip(
              label: 'onSurfaceVariant',
              color: colorScheme.onSurfaceVariant,
              onColor: colorScheme.surfaceVariant,
            ),
            ColorChip(
              label: 'surfaceTint',
              color: colorScheme.surfaceTint,
            ),
          ],
        ),
        divider,
        ColorGroup(
          children: [
            ColorChip(
              label: 'outline',
              color: colorScheme.outline,
            ),
            ColorChip(
              label: 'outlineVariant',
              color: colorScheme.outlineVariant,
            ),
          ],
        ),
        divider,
        ColorGroup(
          children: [
            ColorChip(
              label: 'inverseSurface',
              color: colorScheme.inverseSurface,
              onColor: colorScheme.onInverseSurface,
            ),
            ColorChip(
              label: 'onInverseSurface',
              color: colorScheme.onInverseSurface,
              onColor: colorScheme.inverseSurface,
            ),
            ColorChip(
              label: 'inversePrimary',
              color: colorScheme.inversePrimary,
              onColor: colorScheme.primary,
            ),
          ],
        ),
        divider,
        ColorGroup(
          children: [
            ColorChip(
              label: 'background',
              color: colorScheme.background,
              onColor: colorScheme.onBackground,
            ),
            ColorChip(
              label: 'onBackground',
              color: colorScheme.onBackground,
              onColor: colorScheme.background,
            ),
            ColorChip(
              label: 'scrim',
              color: colorScheme.scrim,
            ),
            ColorChip(
              label: 'shadow',
              color: colorScheme.shadow,
            ),
          ],
        ),
        divider,
      ],
    );
  }
}

class ColorGroup extends StatelessWidget {
  const ColorGroup({super.key, required this.children});

  final List<Widget> children;

  @override
  Widget build(BuildContext context) {
    return RepaintBoundary(
      child: Card(
        clipBehavior: Clip.antiAlias,
        child: Column(
          children: children,
        ),
      ),
    );
  }
}

class ColorChip extends StatelessWidget {
  const ColorChip({
    super.key,
    required this.color,
    required this.label,
    this.onColor,
  });

  final Color color;
  final Color? onColor;
  final String label;

  static Color contrastColor(Color color) {
    final brightness = ThemeData.estimateBrightnessForColor(color);
    switch (brightness) {
      case Brightness.dark:
        return Colors.white;
      case Brightness.light:
        return Colors.black;
    }
  }

  @override
  Widget build(BuildContext context) {
    final Color labelColor = onColor ?? contrastColor(color);

    return Container(
      color: color,
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Row(
          children: [
            Expanded(child: Text(label, style: TextStyle(color: labelColor))),
          ],
        ),
      ),
    );
  }
}