### Basic GraphView Setup and Initialization

Source: https://github.com/nabil6391/graphview/blob/master/README.md

This code demonstrates the fundamental structure for a Flutter application using GraphView. It includes necessary imports, widget setup, and the initialization of the Graph and its controller. Configure layout parameters like sibling separation and level separation using TextFormFields.

```dart
import 'dart:math';

import 'package:flutter/material.dart';
import 'package:graphview/GraphView.dart';

void main() {
  runApp(MyApp());
}

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

  @override
  Widget build(BuildContext context) => MaterialApp(home: TreeViewPage());
}

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

  @override
  State<TreeViewPage> createState() => _TreeViewPageState();
}

class _TreeViewPageState extends State<TreeViewPage> {
  final GraphViewController controller = GraphViewController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        mainAxisSize: MainAxisSize.max,
        children: [
          Wrap(
            children: [
              SizedBox(
                width: 100,
                child: TextFormField(
                  initialValue: builder.siblingSeparation.toString(),
                  decoration: InputDecoration(labelText: "Sibling Separation"),
                  onChanged: (text) {
                    builder.siblingSeparation = int.tryParse(text) ?? 100;
                    setState(() {});
                  },
                ),
              ),
              SizedBox(
                width: 100,
                child: TextFormField(
                  initialValue: builder.levelSeparation.toString(),
                  decoration: InputDecoration(labelText: "Level Separation"),
                  onChanged: (text) {
                    builder.levelSeparation = int.tryParse(text) ?? 100;
                    setState(() {});
                  },
                ),
              ),
              SizedBox(
                width: 100,
                child: TextFormField(
                  initialValue: builder.subtreeSeparation.toString(),
                  decoration: InputDecoration(labelText: "Subtree separation"),
                  onChanged: (text) {
                    builder.subtreeSeparation = int.tryParse(text) ?? 100;
                    setState(() {});
                  },
                ),
              ),
              SizedBox(
                width: 100,
                child: TextFormField(
                  initialValue: builder.orientation.toString(),
                  decoration: InputDecoration(labelText: "Orientation"),
                  onChanged: (text) {
                    builder.orientation = int.tryParse(text) ?? 100;
                    setState(() {});
                  },
                ),
              ),
              ElevatedButton(
                onPressed: () {
                  final node12 = Node.Id(r.nextInt(100));
                  var edge = graph.getNodeAtPosition(r.nextInt(graph.nodeCount()));
                  debugPrint(edge.toString());
                  graph.addEdge(edge, node12);
                  setState(() {});
                },
                child: Text("Add"),
              ),
            ],
          ),
          Expanded(
            child: GraphView.builder(
              graph: graph,
              algorithm: BuchheimWalkerAlgorithm(builder, TreeEdgeRenderer(builder)),
              controller: controller,
              animated: true,
              autoZoomToFit: true,
              builder: (Node node) {
                // I can decide what widget should be shown here based on the id
                var a = node.key?.value as int;
                return rectangleWidget(a);
              },
            ),
          ),
        ],
      ),
    );
  }

  Random r = Random();

  Widget rectangleWidget(int a) {
    return InkWell(
      onTap: () {
        debugPrint('clicked');
      },
      child: Container(
        padding: EdgeInsets.all(16),
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(4),
          boxShadow: [BoxShadow(color: Colors.blue[100]!, spreadRadius: 1)],
        ),
        child: Text('Node $a'),
      ),
    );
  }

  final Graph graph = Graph()..isTree = true;
  BuchheimWalkerConfiguration builder = BuchheimWalkerConfiguration();

  @override
  void initState() {
    super.initState();
    final node1 = Node.Id(1);
    final node2 = Node.Id(2);
    final node3 = Node.Id(3);
    final node4 = Node.Id(4);
    final node5 = Node.Id(5);
    final node6 = Node.Id(6);
    final node8 = Node.Id(7);
    final node7 = Node.Id(8);
    final node9 = Node.Id(9);
    final node10 = Node.Id(10);
    final node11 = Node.Id(11);
    final node12 = Node.Id(12);

    graph.addEdge(node1, node2);

```

--------------------------------

### Create a Node with Custom Widget Content

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Demonstrates how to create a Node object where the content is a custom widget, such as a Container with specific styling and text. This method is now deprecated.

```dart
Node node = Node(getNodeText);

getNodeText() {
    return Container(
        padding: EdgeInsets.all(16),
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(4),
          boxShadow: [
            BoxShadow(color: Colors.blue[100], spreadRadius: 1),
          ],
        ),
        child: Text("Node ${n++}"));
  }
```

--------------------------------

### GraphView Balloon Layout Algorithm

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Renders the graph using the Balloon Layout algorithm, suitable for hierarchical structures.

```dart
GraphView.builder(
  graph: graph,
  algorithm: BalloonLayoutAlgorithm(
    BuchheimWalkerConfiguration(), 
    null
  ),
  builder: (node) => nodeWidget(node),
)
```

--------------------------------

### GraphView Mindmap Layout Algorithm

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Implements the Mindmap layout algorithm for creating mind map visualizations.

```dart
GraphView.builder(
  graph: graph,
  algorithm: MindmapAlgorithm(
    BuchheimWalkerConfiguration(), 
    MindmapEdgeRenderer(config)
  ),
  builder: (node) => nodeWidget(node),
)
```

--------------------------------

### Advanced GraphView Builder Configuration

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Use GraphView.builder for enhanced graph construction with options for animations, auto-zoom, initial node focus, and custom node widgets.

```dart
GraphView.builder(
  graph: graph,
  algorithm: BuchheimWalkerAlgorithm(config, TreeEdgeRenderer(config)),
  controller: controller,
  animated: true,                    // Enable smooth animations
  autoZoomToFit: true,              // Automatically zoom to fit all nodes
  initialNode: ValueKey('startNode'), // Jump to specific node on init
  panAnimationDuration: Duration(milliseconds: 600),
  toggleAnimationDuration: Duration(milliseconds: 400),
  centerGraph: true,                // Center the graph in viewport
  builder: (Node node) {
    return YourCustomWidget(node);
  },
)
```

--------------------------------

### GraphView Navigation and Camera Control

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Programmatically control the graph's view using GraphViewController. Includes methods for jumping, animating to nodes, zooming, resetting, and recalculating layout.

```dart
// Jump to a specific node
controller.jumpToNode(ValueKey('nodeId'));

// Animate to a node
controller.animateToNode(ValueKey('nodeId'));

// Zoom to fit all visible nodes
controller.zoomToFit();

// Reset view to origin
controller.resetView();

// Force recalculation of layout
controller.forceRecalculation();
```

--------------------------------

### Custom Node Widget Builder

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Dynamically build custom widgets for nodes based on their properties, such as their ID.

```dart
Node node = Node.Id(fromNodeId) ;

builder: (Node node) {
                  // I can decide what widget should be shown here based on the id
                  var a = node.key.value as int;
                  if(a ==2)
                    return rectangleWidget(a);
                  else 
                    return circleWidget(a);
                },
```

--------------------------------

### Focusing and Dragging Nodes

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Enable focusing on a specific node, which aids in scrolling and allows for real-time position updates during drag operations in force-directed graphs.

```dart
onPanUpdate: (details) {
        var x = details.globalPosition.dx;
        var y = details.globalPosition.dy;
        setState(() {
          builder.setFocusedNode(graph.getNodeAtPosition(i));
          graph.getNodeAtPosition(i).position = Offset(x,y);
        });
      },
```

--------------------------------

### Configure Graph Layout Builder

Source: https://github.com/nabil6391/graphview/blob/master/README.md

The `builder` object allows customization of the graph layout. Set properties like `siblingSeparation`, `levelSeparation`, `subtreeSeparation`, and `orientation` to control the visual arrangement of nodes and edges.

```dart
builder
  ..siblingSeparation = (100)
  ..levelSeparation = (150)
  ..subtreeSeparation = (150)
  ..orientation = (BuchheimWalkerConfiguration.ORIENTATION_TOP_BOTTOM);
```

--------------------------------

### Build Graph Nodes with Custom Widgets

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Defines a builder function to create custom widgets for each node based on its ID and data from the JSON. This allows for dynamic node rendering.

```dart
 builder: (Node node) {
                  // I can decide what widget should be shown here based on the id
                  var a = node.key.value as int;
                  var nodes = json['nodes'];
                  var nodeValue = nodes.firstWhere((element) => element['id'] == a);
                  return rectangleWidget(nodeValue['label'] as String);
                },
```

--------------------------------

### GraphView Circular Layout Algorithm

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Arranges graph nodes in a circular layout. Configuration options include radius and edge crossing reduction.

```dart
GraphView.builder(
  graph: graph,
  algorithm: CircleLayoutAlgorithm(
    CircleLayoutConfiguration(
      radius: 200.0,
      reduceEdgeCrossing: true,
    ), 
    null
  ),
  builder: (node) => nodeWidget(node),
)
```

--------------------------------

### GraphView Node Expand/Collapse Control

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Manage node visibility using GraphViewController. Supports collapsing, expanding, toggling states, checking collapse status, and setting initially collapsed nodes.

```dart
final controller = GraphViewController();

// Collapse a node (hide its children)
controller.collapseNode(graph, node, animate: true);

// Expand a collapsed node
controller.expandNode(graph, node, animate: true);

// Toggle collapse/expand state
controller.toggleNodeExpanded(graph, node, animate: true);

// Check if node is collapsed
bool isCollapsed = controller.isNodeCollapsed(node);

// Set initially collapsed nodes
controller.setInitiallyCollapsedNodes([node1, node2]);
```

--------------------------------

### GraphView Radial Tree Layout Algorithm

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Applies a Radial Tree Layout algorithm to the graph, often used for tree-like structures.

```dart
GraphView.builder(
  graph: graph,
  algorithm: RadialTreeLayoutAlgorithm(
    BuchheimWalkerConfiguration(), 
    null
  ),
  builder: (node) => nodeWidget(node),
)
```

--------------------------------

### GraphView Tidier Tree Layout Algorithm

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Utilizes the Tidier Tree Layout algorithm for arranging graph nodes, typically in a tree structure.

```dart
GraphView.builder(
  graph: graph,
  algorithm: TidierTreeLayoutAlgorithm(
    BuchheimWalkerConfiguration(), 
    TreeEdgeRenderer(config)
  ),
  builder: (node) => nodeWidget(node),
)
```

--------------------------------

### Coloring Individual Edges

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Assign specific colors to individual edges by passing a Paint object during edge creation. Currently applicable for ArrowEdgeRenderer.

```dart
var a = Node();
var b = Node();
 graph.addEdge(a, b, paint: Paint()..color = Colors.red);
```

--------------------------------

### Add Edges to Graph

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Use `graph.addEdge` to connect nodes. You can optionally specify a `Paint` object to customize the edge's appearance, such as its color. If no paint is provided, default styling is used.

```dart
graph.addEdge(node1, node3, paint: Paint()..color = Colors.red);
graph.addEdge(node1, node4, paint: Paint()..color = Colors.blue);
graph.addEdge(node2, node5);
graph.addEdge(node2, node6);
graph.addEdge(node6, node7, paint: Paint()..color = Colors.red);
graph.addEdge(node6, node8, paint: Paint()..color = Colors.red);
graph.addEdge(node4, node9);
graph.addEdge(node4, node10, paint: Paint()..color = Colors.black);
graph.addEdge(node4, node11, paint: Paint()..color = Colors.red);
graph.addEdge(node11, node12);
```

--------------------------------

### GraphView Custom Edge Paint

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Customize the appearance of edges, including color and stroke width, by providing a custom Paint object.

```dart
getGraphView() {
        return GraphView(
                graph: graph,
                algorithm: SugiyamaAlgorithm(builder),
                paint: Paint()..color = Colors.green..strokeWidth = 1..style = PaintingStyle.stroke,
              );
}
```

--------------------------------

### Define JSON for Graph Data

Source: https://github.com/nabil6391/graphview/blob/master/README.md

This JSON structure defines nodes with IDs and labels, and edges connecting these nodes by their IDs. It serves as input for creating a graph object.

```dart
var json = {
   "nodes": [
     {"id": 1, "label": 'circle'},
     {"id": 2, "label": 'ellipse'},
     {"id": 3, "label": 'database'},
     {"id": 4, "label": 'box'},
     {"id": 5, "label": 'diamond'},
     {"id": 6, "label": 'dot'},
     {"id": 7, "label": 'square'},
     {"id": 8, "label": 'triangle'},
   ],
   "edges": [
     {"from": 1, "to": 2},
     {"from": 2, "to": 3},
     {"from": 2, "to": 4},
     {"from": 2, "to": 5},
     {"from": 5, "to": 6},
     {"from": 5, "to": 7},
     {"from": 6, "to": 8}
   ]
 };
```

--------------------------------

### Add Edges to Graph from JSON

Source: https://github.com/nabil6391/graphview/blob/master/README.md

Iterates through the 'edges' array in the JSON data and adds corresponding edges to the graph object using node IDs. Ensure the graph object is initialized before use.

```dart
  edges.forEach((element) {
      var fromNodeId = element['from'];
      var toNodeId = element['to'];
      graph.addEdge(Node.Id(fromNodeId), Node.Id(toNodeId));
    });
```

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