animated_streaming_markdown 0.1.5

Flutter markdown streaming package for Android/iOS/macOS/Linux/Windows (web is not supported).

animated_streaming_markdown

animated_streaming_markdown is a Flutter package for streaming Markdown workflows with:

• native tree-sitter parsing (FFI)
• incremental parse sessions for append-heavy updates
• streaming-friendly Flutter rendering (StreamingMarkdownRenderView)
• pure-Dart fallback parsing utilities (RopeString, RopeMarkdownParser)

Requirements

• Dart SDK: >=2.17.0 <4.0.0
• Flutter SDK: >=3.0.0
• Runtime targets: Android, iOS, macOS, Linux, Windows
• Web: not supported as a runtime target

Platform Requirements

• Android: Flutter Android toolchain and Android NDK available for FFI/native build steps.
• iOS: Xcode + CocoaPods toolchain.
• macOS: Xcode + CocoaPods toolchain.
• Linux: Flutter Linux desktop enabled, plus C/C++ desktop build tools (cmake, compiler toolchain).
• Windows: Flutter Windows desktop enabled, plus Visual Studio C++ desktop toolchain.
• Web: intentionally unsupported for production runtime use; native APIs are unavailable.

Installation

Add dependency to pubspec.yaml:

dependencies:
  animated_streaming_markdown: ^0.1.5

Install packages:

flutter pub get

Usage

1. Streaming parse + render in UI

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

class StreamingMarkdownPane extends StatefulWidget {
  const StreamingMarkdownPane({super.key});

  @override
  State<StreamingMarkdownPane> createState() => _StreamingMarkdownPaneState();
}

class _StreamingMarkdownPaneState extends State<StreamingMarkdownPane> {
  final StreamingMarkdownParseWorker _worker = StreamingMarkdownParseWorker();
  List<MarkdownRenderNode> _nodes = const <MarkdownRenderNode>[];
  bool _started = false;

  @override
  void initState() {
    super.initState();
    _start();
  }

  Future<void> _start() async {
    await _worker.start();
    setState(() {
      _started = true;
    });
  }

  Future<void> setMarkdown(String text) async {
    if (!_started) return;
    final result = await _worker.request(
      op: 'set',
      text: text,
      includeNodes: true,
    );
    setState(() {
      _nodes = result.renderNodes;
    });
  }

  Future<void> appendMarkdownChunk(String chunk) async {
    if (!_started) return;
    final result = await _worker.request(
      op: 'append',
      text: chunk,
      includeNodes: true,
    );
    setState(() {
      _nodes = result.renderNodes;
    });
  }

  @override
  void dispose() {
    _worker.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return StreamingMarkdownRenderView(
      nodes: _nodes,
      enableTextSelection: true,
      tokenArrivalDelay: const Duration(milliseconds: 25),
      tokenFadeInDuration: const Duration(milliseconds: 140),
    );
  }
}

2. Pure-Dart parsing without native APIs

import 'package:animated_streaming_markdown/animated_streaming_markdown.dart';

final RopeString rope = RopeString();
rope.append('# Hello');
rope.append('\n\nParagraph');

final MarkdownDocument doc = const RopeMarkdownParser().parse(rope);
print(doc.blocks.length);

3. Native parser usage with availability check

import 'package:animated_streaming_markdown/animated_streaming_markdown.dart';

if (isStreamingMarkdownNativeLibraryAvailable) {
  final parser = NativeIncrementalMarkdownParser.create();
  parser.setText('# Title');
  final count = parser.blockCount();
  parser.dispose();
  print(count);
}

Rendering Notes

• StreamingMarkdownRenderView accepts List<MarkdownRenderNode> and renders block-by-block.
• HTML block nodes are rendered with pure Flutter widgets (no embedded WebView).
• HTML blocks wrap content height naturally instead of using a fixed viewport.

Example App

See example/ for a dual-pane chat demo and end-to-end streaming usage.

Bundled Tree-sitter Dependencies

This package vendors only the required native sources under packages/:

• packages/tree-sitter (tree-sitter runtime)
• packages/tree-sitter-markdown (block + inline markdown grammars)

Both bundled upstream components are MIT-licensed. This package remains Apache-2.0.

License

animated_streaming_markdown is licensed under Apache License 2.0. See LICENSE.

Third-party license details are listed in THIRD_PARTY_LICENSES.md.