mermaid_core 0.1.1

Pure Dart port of mermaid.js: detect, parse and lay out 28 diagram types into a backend-agnostic scene, with an SVG renderer and a CLI. No Flutter.

mermaid_core

mermaid_core parses Mermaid source, lays it out, and produces a backend-independent render scene. It includes an SVG renderer and a command-line tool and has no Flutter dependency.

See the live comparison demo for side-by-side output from this implementation and mermaid.js.

The package currently supports 28 diagram types, Mermaid theme directives, look: handDrawn, icons, math in labels, and alternate ELK and tidy-tree layouts. Compatibility notes and known differences from mermaid.js are kept in the repository's parity directory.

Library use

import 'package:mermaid_core/mermaid_core.dart';

void main() {
  const mermaid = Mermaid(measurer: ApproximateTextMeasurer());
  final scene = mermaid.render('''
graph TD
  A[Start] --> B{Works?}
  B -->|yes| C[Ship it]
  B -->|no| A
''');

  print(renderSceneToSvg(scene));
}

Mermaid.render returns a RenderScene containing shapes and text in absolute coordinates. renderSceneToSvg serializes that scene to SVG.

ApproximateTextMeasurer uses bundled metrics suitable for SVG output and tests. Flutter applications should use the TextPainter-based measurer from mermaid_flutter when their layout must match Flutter font rendering.

Command-line tool

Activate the package globally:

$ dart pub global activate mermaid_core
$ mermaid_dart diagram.mmd -o diagram.svg
$ cat diagram.mmd | mermaid_dart --theme dark

The output format is inferred from the file extension. PNG output requires rsvg-convert, resvg, or ImageMagick on PATH.

License

MIT. This package contains code derived from mermaid.js (MIT) and a vendored derivative of dart_dagre (Apache-2.0). See LICENSE and the license under lib/src/vendor/dagre.