spinning_mixed.dart 3.51 KB
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// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

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import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
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import '../rendering/src/solid_color_box.dart';
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// Solid color, RenderObject version
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void addFlexChildSolidColor(RenderFlex parent, Color backgroundColor, { int flex = 0 }) {
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  final RenderSolidColorBox child = RenderSolidColorBox(backgroundColor);
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  parent.add(child);
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  final FlexParentData childParentData = child.parentData! as FlexParentData;
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  childParentData.flex = flex;
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}

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// Solid color, Widget version
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class Rectangle extends StatelessWidget {
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  const Rectangle(this.color, { Key? key }) : super(key: key);
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  final Color color;
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  @override
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  Widget build(BuildContext context) {
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    return Expanded(
      child: Container(
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        color: color,
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      ),
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    );
  }
}

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double? value;
RenderObjectToWidgetElement<RenderBox>? element;
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void attachWidgetTreeToRenderTree(RenderProxyBox container) {
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  element = RenderObjectToWidgetAdapter<RenderBox>(
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    container: container,
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    child: Directionality(
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      textDirection: TextDirection.ltr,
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      child: SizedBox(
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        height: 300.0,
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        child: Column(
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          mainAxisAlignment: MainAxisAlignment.spaceBetween,
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          children: <Widget>[
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            const Rectangle(Color(0xFF00FFFF)),
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            Material(
              child: Container(
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                padding: const EdgeInsets.all(10.0),
                margin: const EdgeInsets.all(10.0),
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                child: Row(
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                  mainAxisAlignment: MainAxisAlignment.spaceAround,
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                  children: <Widget>[
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                    ElevatedButton(
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                      child: Row(
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                        children: <Widget>[
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                          Image.network('https://flutter.dev/images/favicon.png'),
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                          const Text('PRESS ME'),
                        ],
                      ),
                      onPressed: () {
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                        value = value == null ? 0.1 : (value! + 0.1) % 1.0;
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                        attachWidgetTreeToRenderTree(container);
                      },
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                    ),
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                    CircularProgressIndicator(value: value),
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                  ],
                ),
              ),
            ),
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            const Rectangle(Color(0xFFFFFF00)),
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          ],
        ),
      ),
    ),
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  ).attachToRenderTree(WidgetsBinding.instance!.buildOwner!, element);
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}

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Duration? timeBase;
late RenderTransform transformBox;
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void rotate(Duration timeStamp) {
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  timeBase ??= timeStamp;
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  final double delta = (timeStamp - timeBase!).inMicroseconds.toDouble() / Duration.microsecondsPerSecond; // radians
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  transformBox.setIdentity();
  transformBox.rotateZ(delta);
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  WidgetsBinding.instance!.buildOwner!.buildScope(element!);
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}

void main() {
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  final WidgetsBinding binding = WidgetsFlutterBinding.ensureInitialized();
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  final RenderProxyBox proxy = RenderProxyBox();
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  attachWidgetTreeToRenderTree(proxy);
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  final RenderFlex flexRoot = RenderFlex(direction: Axis.vertical);
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  addFlexChildSolidColor(flexRoot, const Color(0xFFFF00FF), flex: 1);
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  flexRoot.add(proxy);
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  addFlexChildSolidColor(flexRoot, const Color(0xFF0000FF), flex: 1);
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  transformBox = RenderTransform(child: flexRoot, transform: Matrix4.identity(), alignment: Alignment.center);
  final RenderPadding root = RenderPadding(padding: const EdgeInsets.all(80.0), child: transformBox);
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  binding.renderView.child = root;
  binding.addPersistentFrameCallback(rotate);
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}