flutter_bangla_math

flutter_bangla_math renders mixed Bangla text and LaTeX math in Flutter without breaking Bengali glyph shaping. It uses flutter_math_fork for TeX rendering and bundles Noto Sans Bengali so it works offline on Android, iOS, web, Linux, macOS, and Windows.

Features

• Inline math with $...$
• Block math with $$...$$
• Fraction layout with BanglaMathFraction
• Inline \bnfrac{...}{...} syntax inside BanglaMathText
• Escaped dollar handling with \$
• Bangla text rendered with bundled Noto Sans Bengali by default
• Inline math baseline alignment tuned for mixed Bangla and math on the same line
• Offline-safe bundled font loading with no runtime font fetching dependency

Installation

dependencies:
  flutter_bangla_math: ^0.4.2

The current package targets Flutter >=3.16.0 and Dart >=3.2.0 <4.0.0.

Usage

import 'package:flutter/material.dart';
import 'package:flutter_bangla_math/flutter_bangla_math.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await ensureBanglaMathFontsLoaded();
  runApp(const DemoApp());
}

class DemoApp extends StatelessWidget {
  const DemoApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: Scaffold(
        body: Padding(
          padding: EdgeInsets.all(24),
          child: BanglaMathText(
            data: r'যদি $a^2+b^2=c^2$ হয়, তবে এটি সমকোণী ত্রিভুজ।',
          ),
        ),
      ),
    );
  }
}

String Literals

Use a raw string when the text contains LaTeX delimiters or backslashes.

const BanglaMathText(
  data: r'ধরি $f(x)=x^2+1$',
);

If you also need new lines, use a normal string with \n, or use a triple-quoted string with real line breaks.

const BanglaMathText(
  data: 'সমীকরণটি হল:\n\n$$\\int_0^1 x^2\\,dx=\\frac{1}{3}$$',
);

const BanglaMathText(
  data: r'''সমীকরণটি হল:

$$\int_0^1 x^2\,dx=\frac{1}{3}$$''',
);

Do not write this if you expect a real line break:

const BanglaMathText(
  data: r'সমীকরণটি হল:\n\n$$\int_0^1 x^2\,dx=\frac{1}{3}$$',
);

That raw string keeps \n as two visible characters because this is normal Dart string behavior.

Examples

Block Math

const BanglaMathText(
  data: r'''সমীকরণটি হল:

$$\int_0^1 x^2\,dx=\frac{1}{3}$$''',
);

Bangla Fraction

const BanglaMathFraction(
  numerator: r'লব $x+1$',
  denominator: r'হর $y+2$',
  style: TextStyle(fontSize: 20),
);

Inline Fraction Syntax

const BanglaMathText(
  data: r'যদি $a^2+b^2=c^2$ হয়, তবে \bnfrac{লব $x+1$}{হর $y+2$} হবে।',
);

Multiple BanglaMathText Widgets

ListView(
  padding: const EdgeInsets.all(24),
  children: const [
    BanglaMathText(
      data: r'প্রথম লাইনে \bnfrac{লব $x+1$}{হর $y+2$} আছে।',
    ),
    SizedBox(height: 12),
    BanglaMathText(
      data: r'দ্বিতীয় লাইনে আবার \bnfrac{লব $x+1$}{হর $y+2$} আছে।',
    ),
  ],
)

If you place many BanglaMathText widgets in a Column, wrap it with SingleChildScrollView or use ListView when the content can exceed the screen height.

Custom Text Style

const BanglaMathText(
  data: r'ধরি $f(x)=x^2+1$',
  style: TextStyle(fontSize: 20, color: Colors.black87),
);

API

BanglaMathText({
  required String data,
  TextStyle? style,
  MathConfig? mathConfig,
  String? fontFamily,
  Locale locale = const Locale('bn'),
  TextAlign textAlign = TextAlign.start,
  bool softWrap = true,
  TextScaler? textScaler,
  MathWidgetCache? cache,
})

BanglaMathFraction({
  required String numerator,
  required String denominator,
  TextStyle? style,
  MathConfig? mathConfig,
  String? fontFamily,
  Locale locale = const Locale('bn'),
  TextAlign textAlign = TextAlign.center,
  bool softWrap = true,
  TextScaler? textScaler,
  MathWidgetCache? cache,
  Color? barColor,
  double barThickness = 1,
  double gap = 4,
  EdgeInsetsGeometry padding = const EdgeInsets.symmetric(horizontal: 4),
})

MathConfig controls inline scaling, block spacing, parser settings, and error fallback styling. BanglaMathFraction reuses the same text and math pipeline, so numerator and denominator strings can contain Bangla text with inline math. BanglaMathText also supports inline \bnfrac{...}{...} tokens in normal paragraph text.

Notes

• Unmatched $ or $$ delimiters fall back to plain text instead of crashing.
• The package bundles only Noto Sans Bengali to keep size lower.
• ensureBanglaMathFontsLoaded() is still available and preloads the bundled font.
• The Noto Sans Bengali OFL text remains in the repository for reference, but it is not bundled into runtime Flutter assets.

Development

flutter pub get
flutter analyze
flutter test