有没有办法在颤振中显示文本内的图像

Question

我有这段代码可以在 flutter 中显示文本中的图像，但是当我使用 ImageShader 时。我收到这个错误 方法 'asset' 没有为类型 'Image' 定义。尝试将名称更正为现有方法的名称，或定义名为 'asset'

的方法

我也提到过这个Repo。这个 repo link 是在 Whosebug 上关于 ImageShader 的先前问题中给出的。
我知道“dart:ui”不包含任何资产方法。所以我使用了 Image.asset 但是当我使用这个方法时我得到了这个错误。

The argument type 'Image (where Image is defined in /Users/username/Developement/flutter/packages/flutter/lib/src/widgets/image.dart)' can't be assigned to the parameter type 'Image (where Image is defined in /Users/username/Developement/flutter/bin/cache/pkg/sky_engine/lib/ui/painting.dart)'

Link to the similar question asked on Whosebug

 import 'dart:ui' as ui;    
    class _MyAppState extends State<MyApp> {
  Float64List matrix4 = new Matrix4.identity().storage;
  ui.Image img;

  Future<ui.Image> getImage() async{
    img = await ui.Image.asset("assets/images/ob_girl_cropped.png"); // This Line Is showing error. Please Help.
  }
  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: Scaffold(
        body: Center(
          child: FutureBuilder(
            future: getImage(),
            builder: (context, snapshot)
            {
              if(snapshot.hasData){
                return Text(
                  'Greetings, planet!',
                  style: TextStyle(
                    fontSize: 40,
                    foreground: Paint()
                      ..shader = ImageShader(
                          img,
                          TileMode.clamp,
                          TileMode.clamp,
                          matrix4),
                  ),
                );
              }
              else{
               return CircularProgressIndicator();
              }
            },
          ),
        ),
      ),
    );
  }
}

Answer 1

两个问题：

加载图像的方式，我写了一个 loadImageFromFile 辅助函数
你不应该把getImage()直接放在future字段中，因为每次重建页面时flutter都会创建一个新的未来（所以多次加载图像）

完整代码：

import 'dart:typed_data';
import 'package:flutter/services.dart' show rootBundle;

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  Float64List matrix4 = new Matrix4.identity().storage;
  Future<ui.Image> imgFuture;

  // New helper function
  Future<ui.Image> loadImageFromFile(String path) async {
    var fileData = Uint8List.sublistView(await rootBundle.load(path));
    return await decodeImageFromList(fileData);
  }

  @override
  void initState() {
    imgFuture = loadImageFromFile("assets/images/ob_girl_cropped.png"); // Works now
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: Scaffold(
        body: Center(
          child: FutureBuilder(
            future: imgFuture,
            builder: (context, snapshot) {
              if (snapshot.hasData) {
                return Text(
                  'Greetings, planet!',
                  style: TextStyle(
                    fontSize: 40,
                    foreground: Paint()..shader = ImageShader(snapshot.data, TileMode.clamp, TileMode.clamp, matrix4),
                  ),
                );
              } else {
                return CircularProgressIndicator();
              }
            },
          ),
        ),
      ),
    );
  }
}

有没有办法在颤振中显示文本内的图像

Is there a way to show image inside text in flutter

text

image

mask

clip

flutter