feat: add dragged property to VertexComponent

CHANGELOG.md

@@ -1,3 +1,15 @@
+## 1.1.4
+- feat: using tag similarity as a layout element.
+    example:
+    ```dart
+    /// @en: Make the repulsion between similar tags smaller
+    /// 
+    /// @zh: 使相似标签之间的排斥力变小
+    CoulombReverseDecorator(sameTagsFactor: 0.8), 
+    ```
+
+- feat: add `dragged` property to `VertexComponent` to indicate whether the vertex is being dragged.
+
 ## 1.1.3+1
 - fix: the crash issue when force is not a number [ForceMotionDecorator].
 

lib/core/algorithm/decorator/pin_decorator.dart

@@ -0,0 +1,20 @@
+// Copyright (c) 2024- All flutter_graph_view authors. All rights reserved.
+//
+// This source code is licensed under Apache 2.0 License.
+
+import 'package:flutter_graph_view/flutter_graph_view.dart';
+
+/// Pin the points that have been dragged in the fixed graph, preventing them from moving
+///
+/// 固定图中被拖拽过的点，防止其移动的装饰器
+class PinDecorator extends ForceDecorator {
+  PinDecorator({super.decorators});
+
+  @override
+  bool needContinue(Vertex v) {
+    if (v.cpn?.dragged == true) {
+      return false;
+    }
+    return true;
+  }
+}

lib/core/graph_algorithm.dart

@@ -50,11 +50,16 @@ abstract class GraphAlgorithm {
   void compute(Vertex v, Graph graph) {
     if (decorators != null) {
       for (var decorator in decorators!) {
+        if (!decorator.needContinue(v)) return;
         decorator.compute(v, graph);
       }
     }
   }
 
+  bool needContinue(Vertex v) {
+    return true;
+  }
+
   /// Called when the graph is loaded.
   @mustCallSuper
   void onLoad(Vertex v) {

lib/widgets/vertex_component.dart

@@ -30,6 +30,7 @@ class VertexComponent extends ShapeComponent
   Options? options;
   GraphComponent? graphComponent;
   ShapeHitbox? hitBox;
+  bool dragged;
 
   VertexComponent(
     this.vertex,
@@ -38,6 +39,7 @@ class VertexComponent extends ShapeComponent
     this.algorithm, {
     this.options,
     this.graphComponent,
+    this.dragged = false,
   }) : super(
           position: vertex.position,
           anchor: Anchor.center,
@@ -135,11 +137,13 @@ class VertexComponent extends ShapeComponent
     }
   }
 
+  @mustCallSuper
   void onDrag(Vector2 globalDelta) {
     if (hasPanel) {
       gameRef.overlays.remove(overlayName);
       gameRef.overlays.add(overlayName);
     }
+    dragged = true;
   }
 
   @override