try

d2layouts/d2cycle/layout.go

@@ -65,6 +65,47 @@ func positionObjects(objects []*d2graph.Object, radius float64) {
 	}
 }
 
+// func createCircularArc(edge *d2graph.Edge) {
+// 	if edge.Src == nil || edge.Dst == nil {
+// 		return
+// 	}
+
+// 	srcCenter := edge.Src.Center()
+// 	dstCenter := edge.Dst.Center()
+
+// 	srcAngle := math.Atan2(srcCenter.Y, srcCenter.X)
+// 	dstAngle := math.Atan2(dstCenter.Y, dstCenter.X)
+// 	if dstAngle < srcAngle {
+// 		dstAngle += 2 * math.Pi
+// 	}
+
+// 	arcRadius := math.Hypot(srcCenter.X, srcCenter.Y)
+
+// 	path := make([]*geo.Point, 0, ARC_STEPS+1)
+// 	for i := 0; i <= ARC_STEPS; i++ {
+// 		t := float64(i) / float64(ARC_STEPS)
+// 		angle := srcAngle + t*(dstAngle-srcAngle)
+// 		x := arcRadius * math.Cos(angle)
+// 		y := arcRadius * math.Sin(angle)
+// 		path = append(path, geo.NewPoint(x, y))
+// 	}
+// 	path[0] = srcCenter
+// 	path[len(path)-1] = dstCenter
+
+// 	// Clamp endpoints to the boundaries of the source and destination boxes.
+// 	_, newSrc := clampPointOutsideBox(edge.Src.Box, path, 0)
+// 	_, newDst := clampPointOutsideBoxReverse(edge.Dst.Box, path, len(path)-1)
+// 	path[0] = newSrc
+// 	path[len(path)-1] = newDst
+
+// 	// Trim redundant path points that fall inside node boundaries.
+// 	path = trimPathPoints(path, edge.Src.Box)
+// 	path = trimPathPoints(path, edge.Dst.Box)
+
+// 	edge.Route = path
+// 	edge.IsCurve = true
+// }
+// createCircularArc creates a circular arc path for the edge and adjusts the last segment to align with the tangent direction.
 func createCircularArc(edge *d2graph.Edge) {
 	if edge.Src == nil || edge.Dst == nil {
 		return
@@ -102,6 +143,26 @@ func createCircularArc(edge *d2graph.Edge) {
 	path = trimPathPoints(path, edge.Src.Box)
 	path = trimPathPoints(path, edge.Dst.Box)
 
+	// Adjust the last segment to align with the tangent direction at the destination
+	if len(path) >= 2 {
+		last := path[len(path)-1]
+		// Calculate tangent direction (perpendicular to radius vector)
+		tangentX := -last.Y
+		tangentY := last.X
+		tangentLength := math.Hypot(tangentX, tangentY)
+		if tangentLength > 0 {
+			// Normalize tangent direction
+			tangentDir := geo.NewPoint(tangentX/tangentLength, tangentY/tangentLength)
+			// Move second-to-last point along the tangent direction
+			delta := 10.0
+			newSecondLast := geo.NewPoint(
+				last.X-delta*tangentDir.X,
+				last.Y-delta*tangentDir.Y,
+			)
+			path[len(path)-2] = newSecondLast
+		}
+	}
+
 	edge.Route = path
 	edge.IsCurve = true
 }

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,