如何绘制文字的形状？

Question

我正在尝试为颤动的标题文本制作动画前景，或者更准确地说，我希望用类似这样的 GIF 来制作文本我什至不知道该怎么做，但我想如果我设法使堆栈充满 GIF 然后使最后一层成为 CustomClipper<Path> 以填充整个 space 但文本形状然后它看起来像它，问题是我不知道如何制作文字形状！另外，除了我将提供的文字形状之外，我不知道如何制作一条只填满整个尺寸的路径，请提供任何帮助，或者如果您有任何想法可以做到这一点，但会以不同的方式我也很感兴趣，在此先感谢。

Answer 1

您可以使用 ImageShader、ShaderMask 和 StreamBuilder（对于 gif）


import 'dart:async';
import 'package:flutter/material.dart';
import 'dart:ui' as ui;

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(
        title: "test",
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {

  Stream<ui.Image> _image;

  @override
  initState() {
    super.initState();
    _image = _getImage();
  }

  Stream<ui.Image> _getImage() {
    var _controller = new StreamController<ui.Image>();
    new AssetImage('assets/b.gif')
        .resolve(new ImageConfiguration())
        .addListener(ImageStreamListener(
            (info, _) {
              _controller.add(info.image);
            }
    ));
    return _controller.stream;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Center(
          child: StreamBuilder<ui.Image>(
            stream: _image,
            builder: (context, data) {
              if (data.data == null)
                return Text('loading');
              return ShaderMask(
                child: Text("Gif !!", style: TextStyle(fontSize: 50),),
                blendMode: BlendMode.srcATop,
                shaderCallback: (bounds) {
                  return ui.ImageShader(
                    data.data,
                    TileMode.repeated,
                    TileMode.repeated,
                    Matrix4.identity().storage,
                  );
                },
              );
            },
          ),
        ));
  }


}

Answer 2

啊，我来晚了..好吧，就这样吧

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        appBar: AppBar(title: const Text('Title')),
        body: Stack(
          children: [
            FakeAnimatedBackground(),
            ShaderMask(
              blendMode: BlendMode.srcOut,
              shaderCallback: (bounds) => LinearGradient(colors: [Colors.black], stops: [0.0]).createShader(bounds),
              child: SizedBox.expand(
                child: Container(
                  color: Colors.transparent,
                  alignment: Alignment.center,
                  child: const Text('SOME TEXT', style: TextStyle(fontSize: 60, fontWeight: FontWeight.bold)),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class FakeAnimatedBackground extends StatefulWidget {
  @override
  _FakeAnimatedBackgroundState createState() => _FakeAnimatedBackgroundState();
}

class _FakeAnimatedBackgroundState extends State<FakeAnimatedBackground> with TickerProviderStateMixin {
  AnimationController _controller;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(duration: const Duration(milliseconds: 5000), vsync: this)..repeat();
  }

  @override
  Widget build(BuildContext context) {
    return RotationTransition(
      alignment: Alignment.center,
      turns: Tween(begin: 0.0, end: 1.0).animate(_controller),
      child: Container(
        decoration: BoxDecoration(
          gradient: SweepGradient(colors: [Colors.red, Colors.green, Colors.blue, Colors.red]),
        ),
      ),
    );
  }
}

FakeAnimationBackgroundclass无所谓，只是模拟背景移动

如何绘制文字的形状？

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dart

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flutter-animation