1 files changed, 92 insertions, 0 deletions
diff --git a/Map/MapRenderComponents/MapEdges.swift b/Map/MapRenderComponents/MapEdges.swift
new file mode 100644
index 0000000..d40d2aa
--- /dev/null
+++ b/Map/MapRenderComponents/MapEdges.swift
@@ -0,0 +1,92 @@
+//
+//  MapEdges.swift
+//  Map
+//
+//  Created by Ruben Beltran del Rio on 2/2/21.
+//
+
+import SwiftUI
+
+struct MapEdges: View {
+
+  @Environment(\.colorScheme) var colorScheme
+
+  let mapSize: CGSize
+  let lineWidth: CGFloat
+  let vertexSize: CGSize
+  let edges: [MapEdge]
+
+  let arrowheadSize = CGFloat(10.0)
+
+  var color: Color {
+    MapColor.colorForScheme(colorScheme).foreground
+  }
+
+  var body: some View {
+    ForEach(edges, id: \.id) { edge in
+      Path { path in
+
+        // First we transform edges from percentage to map coordinates
+        let origin = CGPoint(x: w(edge.origin.x), y: h(edge.origin.y))
+        let destination = CGPoint(x: w(edge.destination.x), y: h(edge.destination.y))
+
+        let slope = (destination.y - origin.y) / (destination.x - origin.x)
+        let angle = atan(slope)
+        let multiplier = CGFloat(slope < 0 ? -1.0 : 1.0)
+        let upperAngle = angle - CGFloat.pi / 4.0
+        let lowerAngle = angle + CGFloat.pi / 4.0
+
+        let offsetOrigin = CGPoint(
+          x: origin.x + multiplier * (vertexSize.width / 2.0) * cos(angle),
+          y: origin.y + multiplier * (vertexSize.height / 2.0) * sin(angle))
+        let offsetDestination = CGPoint(
+          x: destination.x - multiplier * (vertexSize.width / 2.0) * cos(angle),
+          y: destination.y - multiplier * (vertexSize.height / 2.0) * sin(angle))
+
+        path.move(to: offsetOrigin)
+        path.addLine(to: offsetDestination)
+
+        if edge.arrowhead {
+          path.move(to: offsetDestination)
+          path.addLine(
+            to: CGPoint(
+              x: offsetDestination.x - multiplier * arrowheadSize * cos(upperAngle),
+              y:
+                offsetDestination.y - multiplier * arrowheadSize * sin(upperAngle)))
+
+          path.move(to: offsetDestination)
+          path.addLine(
+            to: CGPoint(
+              x: offsetDestination.x - multiplier * arrowheadSize * cos(lowerAngle),
+              y:
+                offsetDestination.y - multiplier * arrowheadSize * sin(lowerAngle)))
+        }
+        path.move(to: offsetDestination)
+        path.closeSubpath()
+      }.applying(
+        CGAffineTransform(translationX: vertexSize.width / 2.0, y: vertexSize.height / 2.0)
+      ).stroke(color, lineWidth: lineWidth)
+    }
+  }
+
+  func h(_ dimension: CGFloat) -> CGFloat {
+    max(0.0, min(mapSize.height, dimension * mapSize.height / 100.0))
+  }
+
+  func w(_ dimension: CGFloat) -> CGFloat {
+    max(0.0, min(mapSize.width, dimension * mapSize.width / 100.0))
+  }
+}
+
+struct MapEdges_Previews: PreviewProvider {
+  static var previews: some View {
+    MapEdges(
+      mapSize: CGSize(width: 400.0, height: 400.0), lineWidth: 1.0,
+      vertexSize: CGSize(width: 25.0, height: 25.0),
+      edges: [
+        MapEdge(
+          id: 1, origin: CGPoint(x: 2.0, y: 34.0), destination: CGPoint(x: 23.0, y: 76.2),
+          arrowhead: true)
+      ])
+  }
+}