try

d2layouts/d2cycle/layout.go

@@ -104,6 +104,43 @@ func createCircularArc(edge *d2graph.Edge) {
 
 	edge.Route = path
 	edge.IsCurve = true
+
+	// Adjust the last segment to ensure proper arrowhead direction
+	if len(edge.Route) >= 2 {
+		lastIndex := len(edge.Route) - 1
+		lastPoint := edge.Route[lastIndex]
+		secondLastPoint := edge.Route[lastIndex-1]
+
+		// Calculate tangent direction (perpendicular to radius vector)
+		tangentX := -lastPoint.Y
+		tangentY := lastPoint.X
+		mag := math.Hypot(tangentX, tangentY)
+		if mag > 0 {
+			tangentX /= mag
+			tangentY /= mag
+		}
+        const MIN_SEGMENT_LEN = 10.0
+		// Calculate current segment direction
+		dx := lastPoint.X - secondLastPoint.X
+		dy := lastPoint.Y - secondLastPoint.Y
+		segLength := math.Hypot(dx, dy)
+		if segLength > 0 {
+			currentDirX := dx / segLength
+			currentDirY := dy / segLength
+
+			// Check if we need to adjust the direction
+			if segLength < MIN_SEGMENT_LEN || (currentDirX*tangentX+currentDirY*tangentY) < 0.999 {
+				// Create new point along tangent direction
+				adjustLength := MIN_SEGMENT_LEN  // Now float64
+				if segLength >= MIN_SEGMENT_LEN {
+					adjustLength = segLength  // Both are float64 now
+				}
+				newSecondLastX := lastPoint.X - tangentX*adjustLength
+				newSecondLastY := lastPoint.Y - tangentY*adjustLength
+				edge.Route[lastIndex-1] = geo.NewPoint(newSecondLastX, newSecondLastY)
+			}
+		}
+	}
 }
 
 

e2etests/testdata/txtar/cycle-diagram/dagre/board.exp.json

@@ -864,8 +864,8 @@
           "y": -37.47600173950195
         },
         {
-          "x": 197.02099609375,
+          "x": 195.6020050048828,
-          "y": -34.3849983215332
+          "y": -42.86199951171875
         },
         {
           "x": 197.2519989013672,
@@ -1228,8 +1228,8 @@
           "y": 197.53700256347656
         },
         {
-          "x": 28.18000030517578,
+          "x": 36.4109992980957,
-          "y": 198.00399780273438
+          "y": 196.90499877929688
         },
         {
           "x": 26.5,
@@ -1592,8 +1592,8 @@
           "y": 37.47600173950195
         },
         {
-          "x": -197.02099609375,
+          "x": -195.6020050048828,
-          "y": 34.3849983215332
+          "y": 42.86199951171875
         },
         {
           "x": -197.2519989013672,
@@ -1972,8 +1972,8 @@
           "y": 111.8030014038086
         },
         {
-          "x": 701.875,
+          "x": 704.7830200195312,
-          "y": 115.77300262451172
+          "y": 107.5770034790039
         },
         {
           "x": 701.4329833984375,
@@ -2336,8 +2336,8 @@
           "y": 186.90899658203125
         },
         {
-          "x": 364.3710021972656,
+          "x": 370.2919921875,
-          "y": 183.8260040283203
+          "y": 190.46800231933594
         },
         {
           "x": 363.6419982910156,
@@ -2740,8 +2740,8 @@
           "y": 196.45700073242188
         },
         {
-          "x": 1003.2860107421875,
+          "x": 1008.4110107421875,
-          "y": 197.53700256347656
+          "y": 196.89300537109375
         },
         {
           "x": 998.5,

e2etests/testdata/txtar/cycle-diagram/elk/board.exp.json

@@ -864,8 +864,8 @@
           "y": -25.47599983215332
         },
         {
-          "x": 209.02099609375,
+          "x": 207.6020050048828,
-          "y": -22.385000228881836
+          "y": -30.86199951171875
         },
         {
           "x": 209.2519989013672,
@@ -1228,8 +1228,8 @@
           "y": 209.53700256347656
         },
         {
-          "x": 40.18000030517578,
+          "x": 48.4109992980957,
-          "y": 210.00399780273438
+          "y": 208.90499877929688
         },
         {
           "x": 38.5,
@@ -1592,8 +1592,8 @@
           "y": 49.47600173950195
         },
         {
-          "x": -185.02099609375,
+          "x": -183.6020050048828,
-          "y": 46.3849983215332
+          "y": 54.86199951171875
         },
         {
           "x": -185.2519989013672,
@@ -1972,8 +1972,8 @@
           "y": 123.8030014038086
         },
         {
-          "x": 674.375,
+          "x": 677.2830200195312,
-          "y": 127.77300262451172
+          "y": 119.5770034790039
         },
         {
           "x": 673.9329833984375,
@@ -2336,8 +2336,8 @@
           "y": 198.90899658203125
         },
         {
-          "x": 336.8710021972656,
+          "x": 342.7919921875,
-          "y": 195.8260040283203
+          "y": 202.46800231933594
         },
         {
           "x": 336.1419982910156,
@@ -2740,8 +2740,8 @@
           "y": 208.45700073242188
         },
         {
-          "x": 936.197021484375,
+          "x": 941.3209838867188,
-          "y": 209.53700256347656
+          "y": 208.89300537109375
         },
         {
           "x": 931.4099731445312,