smart_latex 2.1.0

Self-contained Flutter LaTeX rendering with bundled KaTeX metrics, input repair, RTL-safe layout, and no extra math package.

example/lib/main.dart

import 'dart:typed_data';

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

void main() => runApp(const ExampleApp());

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'smart_latex example',
      theme: ThemeData(useMaterial3: true),
      home: const _HomePage(),
    );
  }
}

class _HomePage extends StatelessWidget {
  const _HomePage();

  @override
  Widget build(BuildContext context) {
    final bodyStyle = Theme.of(context).textTheme.bodyLarge!.copyWith(
          height: 1.8,
        );

    final items = <Widget>[
      // Inline math mixed with text.
      SmartLatexText(
        r'The quadratic formula is $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$.',
        style: bodyStyle,
      ),

      // Display (block) math via SmartMath.
      const SmartMath(r'e^{i\pi} + 1 = 0', display: true),

      // Display math via $$...$$ inside SmartLatexText.
      SmartLatexText(
        r'$$\int_0^\infty e^{-x^2}\,dx = \frac{\sqrt{\pi}}{2}$$',
        style: bodyStyle,
      ),

      // Unicode math symbols typed directly are converted to LaTeX.
      SmartLatexText(r'Circle area: $A = π × r²$', style: bodyStyle),

      // Currency is kept as plain text, not parsed as a $...$ math span.
      SmartLatexText('Subtotal \$5, tax \$1, total \$6.', style: bodyStyle),

      // Long-press a formula to copy its LaTeX source.
      Builder(
        builder: (context) => SmartLatexText(
          r'Long-press to copy: $a^2 + b^2 = c^2$',
          style: bodyStyle,
          copyableMath: true,
          onMathCopied: (tex) => ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(content: Text('Copied: $tex')),
          ),
        ),
      ),

      // Export a rendered formula to a PNG.
      const _ExportDemo(),

      // Malformed input: Persian digits + double backslash + \text wrappers.
      SmartLatexText(
        r'حاصل عبارت $\frac{{\text{0}\text{٫}\overline{\text{3}}-\text{0}\text{٫}\text{5}}}'
        r'{{\sqrt{{{\left(\text{1}-\text{2}\sqrt{{\text{2}}}\\right)}^{\text{2}}}}-\sqrt{{\text{8}}}-\text{1}}}$ کدام است؟',
        textDirection: TextDirection.rtl,
        style: bodyStyle,
      ),

      // RTL text with a small inline formula.
      SmartLatexText(
        r'قضیه فیثاغورس: $a^2 + b^2 = c^2$',
        textDirection: TextDirection.rtl,
        style: bodyStyle,
      ),
    ];

    return Scaffold(
      appBar: AppBar(title: const Text('smart_latex')),
      body: ListView.separated(
        padding: const EdgeInsets.all(16),
        itemCount: items.length,
        separatorBuilder: (_, __) => const Divider(height: 32),
        itemBuilder: (_, i) => items[i],
      ),
    );
  }
}

/// Renders a formula and exports it to a PNG via [captureLatexPng].
class _ExportDemo extends StatefulWidget {
  const _ExportDemo();

  @override
  State<_ExportDemo> createState() => _ExportDemoState();
}

class _ExportDemoState extends State<_ExportDemo> {
  final GlobalKey _key = GlobalKey();
  Uint8List? _png;

  Future<void> _export() async {
    final bytes = await captureLatexPng(_key);
    if (mounted) setState(() => _png = bytes);
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        SmartMath(r'\oint_C \vec{F} \cdot d\vec{r}', boundaryKey: _key),
        const SizedBox(height: 8),
        FilledButton.tonal(
          onPressed: _export,
          child: const Text('Export to PNG'),
        ),
        if (_png != null) ...[
          const SizedBox(height: 8),
          const Text('Exported image:'),
          Image.memory(_png!, height: 48),
        ],
      ],
    );
  }
}