https://github.com/sachaarbonel/epsilon.dart
A library for drawing graph data structures (Graph Theory)
https://github.com/sachaarbonel/epsilon.dart
dart flutter graph graph-drawing graph-theory
Last synced: 6 months ago
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A library for drawing graph data structures (Graph Theory)
- Host: GitHub
- URL: https://github.com/sachaarbonel/epsilon.dart
- Owner: sachaarbonel
- Created: 2020-02-07T08:50:52.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2020-02-11T11:04:50.000Z (over 5 years ago)
- Last Synced: 2025-04-09T16:21:21.103Z (6 months ago)
- Topics: dart, flutter, graph, graph-drawing, graph-theory
- Language: Dart
- Homepage:
- Size: 6.65 MB
- Stars: 8
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
Awesome Lists containing this project
README
# Epsilon
Epsilon is a Dart library dedicated to graph drawing.
"Epsilon" in reference to the mathematics way to denote the number of edges of a graph.
## Usage
A simple usage example:
```dart
import 'package:flutter/material.dart';
import 'package:epsilon/epsilon.dart';
import 'package:vector_math/vector_math_64.dart' hide Colors;
final Color darkBlue = Color.fromARGB(255, 18, 32, 47);
class MyApp extends StatefulWidget {
MyApp();
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State {
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
debugShowCheckedModeBanner: false,
home: Scaffold(
body: Center(
child: Epsilon(
onNodeSelect: (Node node) {
print('touching id ${node.id}');
print('touching label ${node.label}');
},
graph: Graph(nodes: [
Node(
id: 'n0',
label: 'A node',
position: Vector2(0, 0),
radius: 30),
Node(
id: 'n1',
label: 'Another node',
position: Vector2(300, 100),
radius: 20),
Node(
id: 'n2',
label: 'And a last one',
position: Vector2(100, 300),
radius: 20)
], edges: [
Edge(id: 'e0', source: 'n0', target: 'n1'),
Edge(id: 'e1', source: 'n1', target: 'n2'),
Edge(id: 'e2', source: 'n2', target: 'n0')
]),
),
),
),
);
}
}
void main() {
runApp(MyApp());
}
```
Need to display Node with a different shape that a simple circle ? No problem we got you covered. Just define a define renderer like this :
```dart
import 'dart:math' as math;
void drawStar(Canvas canvas, double cx, double cy, int spikes, int outerRadius,
int innerRadius) {
var rot = math.pi / 2 * 3;
var x = cx;
var y = cy;
var step = math.pi / spikes;
final paint = Paint()
..strokeWidth = 5
..style = PaintingStyle.stroke
..color = Colors.blue;
final path = Path()..moveTo(cx, cy - outerRadius);
for (var i = 0; i < spikes; i++) {
x = cx + math.cos(rot) * outerRadius;
y = cy + math.sin(rot) * outerRadius;
path.lineTo(x, y);
rot += step;
x = cx + math.cos(rot) * innerRadius;
y = cy + math.sin(rot) * innerRadius;
path.lineTo(x, y);
rot += step;
}
path.lineTo(cx, cy - outerRadius);
path.close();
canvas.drawPath(path, paint);
}
class MyNodeRenderer extends NodeRenderer {
@override
void renderNode(Canvas canvas, Offset center, double radius, Paint paint) {
drawStar(canvas, center.dx, center.dy, 5, 30, 15);
}
}
```
## TODOs
- [ ] fix center canvas
- [ ] add support for shaders
- [ ] add support for legend
- [ ] add support for graph theory algorithms (for example : on click highlight neighbours)
- [ ] support some physics
- [ ] add possibility to edit nodes on the fly (add, delete, remove, attach edge to another node)
## Features and bugs
Please file feature requests and bugs at the [issue tracker][tracker].
[tracker]: http://example.com/issues/replaceme