stack.dart

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';

import 'package:flutter/material.dart';

import 'diagram_step.dart';

const String _stack = 'stack';
const String _stackWithGradient = 'stack_with_gradient';

class StackDiagram extends StatelessWidget with DiagramMetadata {
  const StackDiagram(this.name, {super.key});

  @override
  final String name;

  @override
  Widget build(BuildContext context) {
    Widget returnWidget;
    switch (name) {
      case _stack:
        returnWidget = Stack(
          children: <Widget>[
            Container(width: 100, height: 100, color: Colors.red),
            Container(width: 90, height: 90, color: Colors.green),
            Container(width: 80, height: 80, color: Colors.blue),
          ],
        );
        break;
      case _stackWithGradient:
        returnWidget = Stack(
          children: <Widget>[
            Container(width: 250, height: 250, color: Colors.white),
            Container(
              padding: const EdgeInsets.all(5.0),
              alignment: Alignment.bottomCenter,
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topCenter,
                  end: Alignment.bottomCenter,
                  colors: <Color>[
                    Colors.black.withAlpha(0),
                    Colors.black12,
                    Colors.black45,
                  ],
                ),
              ),
              child: const Text(
                'Foreground Text',
                style: TextStyle(color: Colors.white, fontSize: 20.0),
              ),
            ),
          ],
        );
        break;
      default:
        returnWidget = const Text('Error');
        break;
    }
    return ConstrainedBox(
      key: UniqueKey(),
      constraints: BoxConstraints.tight(const Size(400.0, 250.0)),
      child: Container(
        alignment: FractionalOffset.center,
        padding: const EdgeInsets.all(5.0),
        color: Colors.white,
        child: returnWidget,
      ),
    );
  }
}

class StackDiagramStep extends DiagramStep {
  @override
  final String category = 'widgets';

  @override
  Future<List<StackDiagram>> get diagrams async => <StackDiagram>[
    const StackDiagram(_stack),
    const StackDiagram(_stackWithGradient),
  ];
}