From 5fa66400e90377b11269f92a2cb45b8c8cc80393 Mon Sep 17 00:00:00 2001
From: li3zhen1 <master_lee@live.com>
Date: Sun, 5 Nov 2023 15:02:21 -0500
Subject: [PATCH] Add Link Rendering

---
 README.md                                    |  6 +--
 Sources/Grape/Views/ForceDirectedGraph.swift | 40 ++++++++++++++++----
 2 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index 1977f20..55533c9 100644
--- a/README.md
+++ b/README.md
@@ -66,15 +66,13 @@ Source code: [ForceDirectedGraph3D/ContentView.swift](https://github.com/li3zhen
 
 ## Usage
 
-### `Grape` (WIP)
-
-`Grape` provides a SwiftUI view `ForceDirectedGraph`:
+### `Grape`
 
 > [!IMPORTANT]
 > `ForceDirectedGraph` is only a minimal working example. Please refer to the next section to create a more complex view.
 
 ```swift
-struct ForceDirectedGraphSwiftUIExample: View {
+struct MyGraph: View {
     let graphController = ForceDirectedGraph2DController<Int>()
     var body: some View {
         ForceDirectedGraph(controller: graphController) {
diff --git a/Sources/Grape/Views/ForceDirectedGraph.swift b/Sources/Grape/Views/ForceDirectedGraph.swift
index dfd4370..a4d87d2 100644
--- a/Sources/Grape/Views/ForceDirectedGraph.swift
+++ b/Sources/Grape/Views/ForceDirectedGraph.swift
@@ -27,18 +27,44 @@ public struct ForceDirectedGraph<NodeID: Hashable>: View {
             let centerX = cgSize.width / 2.0
             let centerY = cgSize.height / 2.0
 
+            for i in self.content.links {
+                let source = self.nodeIdToIndexLookup[i.id.source]!
+                let target = self.nodeIdToIndexLookup[i.id.target]!
+
+                let sourceX = centerX + model.simulation.nodePositions[source].x
+                let sourceY = centerY + model.simulation.nodePositions[source].y
+                let targetX = centerX + model.simulation.nodePositions[target].x
+                let targetY = centerY + model.simulation.nodePositions[target].y
+
+                context.stroke(
+                    Path { path in
+                        path.move(to: CGPoint(x: sourceX, y: sourceY))
+                        path.addLine(to: CGPoint(x: targetX, y: targetY))
+                    },
+                    with: .color(i.strokeColor),
+                    style: StrokeStyle(lineWidth: i.strokeWidth)
+                )
+            }
+
             for i in model.simulation.nodePositions.indices {
                 let node = content.nodes[i]
-                let x = centerX + model.simulation.nodePositions[i].x
-                let y = centerY + model.simulation.nodePositions[i].y
+                let x = centerX + model.simulation.nodePositions[i].x - node.radius
+                let y = centerY + model.simulation.nodePositions[i].y - node.radius
 
-                let rect = CGRect(origin: .init(x: x, y: y), size: CGSize(width: 8.0, height: 8.0))
+                let rect = CGRect(
+                    origin: .init(x: x, y: y),
+                    size: CGSize(
+                        width: node.radius * 2, height: node.radius * 2
+                    )
+                )
 
                 context.fill(
                     Path(ellipseIn: rect), with: .color(node.fill))
-                context.stroke(
-                    Path(ellipseIn: rect), with: .color(Color(nsColor: .windowBackgroundColor)),
-                    style: StrokeStyle(lineWidth: 1.5))
+                if let strokeColor = node.strokeColor {
+                    context.stroke(
+                        Path(ellipseIn: rect), with: .color(Color(strokeColor)),
+                        style: StrokeStyle(lineWidth: node.strokeWidth))
+                }
             }
         }
     }
@@ -97,7 +123,7 @@ public struct ForceDirectedGraph<NodeID: Hashable>: View {
                 forceDescriptor.attachToSimulation(simulation)
             }
         }
-        
+
         self.nodeIdToIndexLookup = lookup
         let model = ForceDirectedGraph2DLayoutEngine(
             initialSimulation: simulation