Flutter 约束框中的颤振图标小部件

在上面的代码中，如果我将图标小部件替换为图像或文本，它们将保持在ConstrainedBox边界，但图标将变为全尺寸！为什么?

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您可以复制下面的粘贴运行完整代码
因为在

Icon

的源代码中，它实际上使用了

RichText

和

textfoverflow.visible

源代码链接

源代码的代码段

class MyHome extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(),
        body: Container(
          child: ConstrainedBox(
            constraints: BoxConstraints(
              maxHeight: 100,
              maxWidth: 100,
            ),
            child: Icon(
              Icons.backup,
              size: 200,
            ),
          ),
        ));
  }
}

工作演示使用

RichText

Widget iconWidget = RichText(
  overflow: TextOverflow.visible, // Never clip.
  textDirection: textDirection, // Since we already fetched it for the assert...
  text: TextSpan(
    text: String.fromCharCode(icon!.codePoint),
    style: TextStyle(
      inherit: false,
      color: iconColor,
      fontSize: iconSize,
      fontFamily: icon!.fontFamily,
      package: icon!.fontPackage,
    ),
  ),
);

完整代码使用

RichText

Widget iconWidget = RichText(
  overflow: TextOverflow.visible, // Never clip.
  textDirection: textDirection, // Since we already fetched it for the assert...
  text: TextSpan(
    text: String.fromCharCode(icon!.codePoint),
    style: TextStyle(
      inherit: false,
      color: iconColor,
      fontSize: iconSize,
      fontFamily: icon!.fontFamily,
      package: icon!.fontPackage,
    ),
  ),
);