re_highlight 0.0.2

Re-Highlight is a powerful text syntax highlighting library.

example/lib/main.dart

import 'package:flutter/material.dart';
import 'package:re_highlight/languages/all.dart';
import 'package:re_highlight/re_highlight.dart';
import 'package:re_highlight/styles/all.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {

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

}

class _MyHomePageState extends State<MyHomePage> {

  String? _language;
  String? _theme;

  final CodeThemeController _controller = CodeThemeController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Highlighting by Reqable'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(10),
        child: Column(
          children: [
            Row(
              children: [
                SizedBox(
                  width: 100,
                  child: Text('Language'),
                ),
                DropdownButton<String>(
                  items: builtinAllLanguages.keys.map(
                    (language) => DropdownMenuItem<String>(
                      value: language,
                      child: Text(language)
                    )
                  ).toList(),
                  value: _language,
                  onChanged: (value) {
                    setState(() {
                      _language = value;
                      _controller.languages = value == null ? const [] : [value];
                    });
                  }
                ),
              ],
            ),
            Row(
              children: [
                SizedBox(
                  width: 100,
                  child: Text('Theme'),
                ),
                DropdownButton<String>(
                  items: builtinAllThemes.keys.map(
                    (theme) => DropdownMenuItem<String>(
                      value: theme,
                      child: Text(theme)
                    )
                  ).toList(),
                  value: _theme,
                  onChanged: (value) {
                    setState(() {
                      _theme = value;
                      _controller.theme = value == null ? const {} : builtinAllThemes[value] ?? const {};
                    });
                  }
                ),
              ],
            ),
            Expanded(
              child: Container(
                child: TextField(
                  controller: _controller,
                  maxLines: null,
                  expands: true,
                  textAlign: TextAlign.start,
                  textAlignVertical: TextAlignVertical.top,
                  decoration: InputDecoration(
                    border: OutlineInputBorder()
                  )
                ),
              )
            )
          ]
        ),
      ),
    );
  }
}

class CodeThemeController extends TextEditingController {

  List<String> languages;
  Map<String, TextStyle> theme;

  late final Highlight _highlight;

  CodeThemeController({
    String? text,
    this.languages = const [],
    this.theme = const {},
  }) {
    _highlight = Highlight();
    _highlight.registerLanguages(builtinAllLanguages);
  }

  @override
  TextSpan buildTextSpan({
    required BuildContext context,
    TextStyle? style,
    required bool withComposing
  }) {
    if (languages.isEmpty || theme.isEmpty) {
      return super.buildTextSpan(
        context: context,
        style: style,
        withComposing: withComposing
      );
    }
    final HighlightResult result = _highlight.highlightAuto(text, languages);
    final TextSpanRenderer renderer = TextSpanRenderer(style, theme);
    result.render(renderer);
    return renderer.span ?? super.buildTextSpan(
      context: context,
      style: style,
      withComposing: withComposing
    );
  }

}