exsurgat 0.1.0

GABC renderer for Flutter.

exsurgat

Flutter package for rendering Gregorian chant from GABC notation.

exsurgat parses GABC source and draws chant staves, neumes, lyrics, titles, annotations directly in Flutter widgets and exports to SVG or PNG.

Features

• Compile Gregorian chant from GABC source
• Display the sheet as a scrollable or non-scrollable Flutter widget
• Export to SVG or PNG
• Customize layout and colors

Getting started

Add exsurgat to dependencies in pubspec.yaml.

dependencies:
  exsurgat:

For correct rendering of {greextra} codes you'll also need to add a font.

flutter:
  fonts:
    - family: greextra
      fonts:
        - asset: packages/exsurgat/fonts/greextra.otf

Import package:

import 'package:exsurgat/exsurgat.dart';

Basic usage

Use ChantScoreView to render a scrollable sheet from a GABC source string with a desired line width and padding:

String source = '''
annotation: Ant
mode: 7 a
title: Exsurgat Deus
text-right: <b>Ps 68 (67)</b>
%%
(c3)Ex(e)súr(g)gat(h) De(ihji)us,(i) *(,) et(i) dis(j)si(i)pén(hg)tur(ef) in(g)i(h)mí(f)ci(f) e(e)ius.(e) (::)
''';
return ChantScoreView(
  useDropCap: true,
  width: 800,
  padding: const EdgeInsets.all(12),
  gabc: source,
);

For a non-scrollable widget that fills available space, use ChantScoreBody instead.

ChantScoreView uses ChantScoreBody internally.

Customization

Use ChantTheme to customize fonts, sizes and colors of the sheet.

ChantScoreView(
  gabc: source,
  useDropCap: true,
  width: 800,
  padding: const EdgeInsets.all(12),
  theme: ChantTheme(
    textColor: Colors.brown,
    rubricColor: ChantColors.rubric,
    neumeColor: Colors.indigo,
    staffLineColor: ChantColors.nigric,
    dividerLineColor: Colors.blueGrey,
    baseTextStyle: BaseTextStyle(
      font: GoogleFonts.imFellDwPica().fontFamily!,
      size: 16,
    ),
    supertitle: TextStyleDefinition(relativeSize: (size) => (size * 7) / 6),
    title: TextStyleDefinition(relativeSize: (size) => (size * 3) / 2),
    subtitle: TextStyleDefinition(relativeSize: (size) => size),
    leftRight: TextStyleDefinition(relativeSize: (size) => size * 0.9),
    annotation: TextStyleDefinition(relativeSize: (size) => (size * 2) / 3),
    dropCap: TextStyleDefinition(
      font: 'Lombardic',
      relativeSize: (size) => size * 4,
      color: Colors.deepOrange,
    ),
    aboveLine: TextStyleDefinition(relativeSize: (size) => size),
    choralSign: TextStyleDefinition(size: (ctxt) => ctxt.staffInterval * 1.5),
    lyric: TextStyleDefinition(relativeSize: (size) => size * 0.9),
    translation: TextStyleDefinition(relativeSize: (size) => size * 0.75),
  ),
)

SVG rendering

To export chant engraving to Scalable Vector Format - write code similar to the following snippet:

final renderingContext = ChantContext(textMeasuringStrategy: .svg);
final score =
    ChantScore(
        ctxt: renderingContext,
        mappings: Gabc.createMappingsFromSource(renderingContext, source),
        header: GabcHeader.fromSource(source),
        useDropCap: true,
      )
      ..performLayout(renderingContext)
      ..layoutChantLines(renderingContext, 800);
final xml = score.createSvgNode(renderingContext).toXmlString();
await File('output.svg').writeAsString(xml);

Bitmap rendering

To export chant engraving to Portable Network Graphics - write code similar to the following snippet:

final renderingContext = ChantContext(textMeasuringStrategy: .canvas);
final score =
    ChantScore(
        ctxt: renderingContext,
        mappings: Gabc.createMappingsFromSource(renderingContext, source),
        header: GabcHeader.fromSource(source),
        useDropCap: true,
      )
      ..performLayout(renderingContext)
      ..layoutChantLines(renderingContext, 800);
final image = await score.createImage(renderingContext, scale: 2);
final png = await image.toByteData(format: .png);
await File('output.png').writeAsBytes(png!.buffer.asInt8List());

Example app

The example/ folder includes a live editor that updates chant rendering as you type GABC source.

License

MIT license. See LICENSE for details.

Credits

This project started as a Dart port of a JavaScript project exsurge created by Fr. Matthew Spencer OSJ and maintained by Benjamin Bloomfield.

Support

• Buy me a coffee

• Donate eCash (XEC)