From 9e30905e0a0f3d5d9efe04ca8f22f31d089a0a99 Mon Sep 17 00:00:00 2001
From: Krishna Subramanian <krishna.subramanian@devolo.de>
Date: Fri, 9 Jun 2023 17:38:04 +0200
Subject: [PATCH] Add option to draw Sugiyama edges without triangles

---
 lib/layered/SugiyamaAlgorithm.dart     |  2 +-
 lib/layered/SugiyamaConfiguration.dart |  2 ++
 lib/layered/SugiyamaEdgeRenderer.dart  | 31 ++++++++++++++++++--------
 3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/lib/layered/SugiyamaAlgorithm.dart b/lib/layered/SugiyamaAlgorithm.dart
index 8e2a649..e03525d 100644
--- a/lib/layered/SugiyamaAlgorithm.dart
+++ b/lib/layered/SugiyamaAlgorithm.dart
@@ -16,7 +16,7 @@ class SugiyamaAlgorithm extends Algorithm {
   var nodeCount = 1;
 
   SugiyamaAlgorithm(this.configuration) {
-    renderer = SugiyamaEdgeRenderer(nodeData, edgeData, configuration.bendPointShape);
+    renderer = SugiyamaEdgeRenderer(nodeData, edgeData, configuration.bendPointShape, configuration.addTriangleToEdge);
   }
 
   int get dummyId => 'Dummy ${nodeCount++}'.hashCode;
diff --git a/lib/layered/SugiyamaConfiguration.dart b/lib/layered/SugiyamaConfiguration.dart
index 0bcc442..a8641b7 100644
--- a/lib/layered/SugiyamaConfiguration.dart
+++ b/lib/layered/SugiyamaConfiguration.dart
@@ -18,6 +18,8 @@ class SugiyamaConfiguration {
   BendPointShape bendPointShape = SharpBendPointShape();
   CoordinateAssignment coordinateAssignment = CoordinateAssignment.Average;
 
+  bool addTriangleToEdge = true;
+
   int getLevelSeparation() {
     return levelSeparation;
   }
diff --git a/lib/layered/SugiyamaEdgeRenderer.dart b/lib/layered/SugiyamaEdgeRenderer.dart
index a0dce24..a7ab267 100644
--- a/lib/layered/SugiyamaEdgeRenderer.dart
+++ b/lib/layered/SugiyamaEdgeRenderer.dart
@@ -4,8 +4,9 @@ class SugiyamaEdgeRenderer extends ArrowEdgeRenderer {
   Map<Node, SugiyamaNodeData> nodeData;
   Map<Edge, SugiyamaEdgeData> edgeData;
   BendPointShape bendPointShape;
+  bool addTriangleToEdge;
 
-  SugiyamaEdgeRenderer(this.nodeData, this.edgeData, this.bendPointShape);
+  SugiyamaEdgeRenderer(this.nodeData, this.edgeData, this.bendPointShape, this.addTriangleToEdge);
 
   var path = Path();
 
@@ -51,9 +52,6 @@ class SugiyamaEdgeRenderer extends ArrowEdgeRenderer {
               bendPoints[size - 4], bendPoints[size - 3], bendPoints[size - 2], bendPoints[size - 1], destination);
         }
 
-        final triangleCentroid = drawTriangle(
-            canvas, edgeTrianglePaint ?? trianglePaint, clippedLine[0], clippedLine[1], clippedLine[2], clippedLine[3]);
-
         path.reset();
         path.moveTo(bendPoints[0], bendPoints[1]);
 
@@ -83,7 +81,16 @@ class SugiyamaEdgeRenderer extends ArrowEdgeRenderer {
           _drawSharpBendPointsEdge(bendPointsWithoutDuplication);
         }
 
-        path.lineTo(triangleCentroid[0], triangleCentroid[1]);
+        if (addTriangleToEdge) {
+          final triangleCentroid = drawTriangle(
+              canvas, edgeTrianglePaint ?? trianglePaint, clippedLine[0], clippedLine[1], clippedLine[2], clippedLine[3]);
+
+          path.lineTo(triangleCentroid[0], triangleCentroid[1]);
+        } else {
+          final stopX = x1 + destination.width / 2;
+          final stopY = y1 + destination.height / 2;
+          path.lineTo(stopX, stopY);
+        }
         canvas.drawPath(path, currentPaint);
       } else {
         final startX = x + source.width / 2;
@@ -93,11 +100,17 @@ class SugiyamaEdgeRenderer extends ArrowEdgeRenderer {
 
         clippedLine = clipLine(startX, startY, stopX, stopY, destination);
 
-        final triangleCentroid = drawTriangle(
-            canvas, edgeTrianglePaint ?? trianglePaint, clippedLine[0], clippedLine[1], clippedLine[2], clippedLine[3]);
+        if (addTriangleToEdge) {
+          final triangleCentroid = drawTriangle(
+              canvas, edgeTrianglePaint ?? trianglePaint, clippedLine[0],
+              clippedLine[1], clippedLine[2], clippedLine[3]);
 
-        canvas.drawLine(
-            Offset(clippedLine[0], clippedLine[1]), Offset(triangleCentroid[0], triangleCentroid[1]), currentPaint);
+          canvas.drawLine(
+              Offset(clippedLine[0], clippedLine[1]), Offset(triangleCentroid[0], triangleCentroid[1]), currentPaint);
+        } else {
+          canvas.drawLine(
+              Offset(clippedLine[0], clippedLine[1]), Offset(stopX, stopY), currentPaint);
+        }
       }
     });
   }