render unfilled triangle arrowhead

d2exporter/export.go

@@ -202,7 +202,7 @@ func toConnection(edge *d2graph.Edge, theme *d2themes.Theme) d2target.Connection
 
 	if edge.SrcArrow {
 		connection.SrcArrow = d2target.DefaultArrowhead
-		if edge.SrcArrowhead != nil && edge.SrcArrowhead.Shape.Value != "" {
+		if edge.SrcArrowhead != nil {
 			connection.SrcArrow = edge.SrcArrowhead.ToArrowhead()
 		}
 	}
@@ -220,7 +220,7 @@ func toConnection(edge *d2graph.Edge, theme *d2themes.Theme) d2target.Connection
 	}
 	if edge.DstArrow {
 		connection.DstArrow = d2target.DefaultArrowhead
-		if edge.DstArrowhead != nil && edge.DstArrowhead.Shape.Value != "" {
+		if edge.DstArrowhead != nil {
 			connection.DstArrow = edge.DstArrowhead.ToArrowhead()
 		}
 	}

d2graph/d2graph.go

@@ -177,10 +177,6 @@ func (a *Attributes) ApplyTextTransform() {
 }
 
 func (a *Attributes) ToArrowhead() d2target.Arrowhead {
-	if a.Shape.Value == "" {
-		return d2target.NoArrowhead
-	}
-
 	var filled *bool
 	if a.Style.Filled != nil {
 		v, _ := strconv.ParseBool(a.Style.Filled.Value)

d2renderers/d2svg/d2svg.go

@@ -145,17 +145,18 @@ func arrowheadMarker(isTarget bool, id string, connection d2target.Connection) s
 		polygonEl.ClassName = "connection"
 		polygonEl.Attributes = fmt.Sprintf(`stroke-width="%d"`, connection.StrokeWidth)
 
+		inset := strokeWidth / 2
 		if isTarget {
 			polygonEl.Points = fmt.Sprintf("%f,%f %f,%f %f,%f",
-				0., 0.,
-				width, height/2.0,
-				0., height,
+				inset, inset,
+				width-inset, height/2.0,
+				inset, height-inset,
 			)
 		} else {
 			polygonEl.Points = fmt.Sprintf("%f,%f %f,%f %f,%f",
-				width, 0.,
-				0., height/2.0,
-				width, height,
+				width-inset, inset,
+				inset, height/2.0,
+				width-inset, height-inset,
 			)
 		}
 		path = polygonEl.Render()

d2target/d2target.go

@@ -784,6 +784,10 @@ func ToArrowhead(arrowheadType string, filled *bool) Arrowhead {
 	case string(CfManyRequired):
 		return CfManyRequired
 	default:
+		if DefaultArrowhead == TriangleArrowhead &&
+			filled != nil && !(*filled) {
+			return UnfilledTriangleArrowhead
+		}
 		return DefaultArrowhead
 	}
 }
@@ -797,11 +801,16 @@ func (arrowhead Arrowhead) Dimensions(strokeWidth float64) (width, height float6
 		baseHeight = 4
 		widthMultiplier = 4
 		heightMultiplier = 4
-	case TriangleArrowhead, UnfilledTriangleArrowhead:
+	case TriangleArrowhead:
 		baseWidth = 4
 		baseHeight = 4
 		widthMultiplier = 3
 		heightMultiplier = 4
+	case UnfilledTriangleArrowhead:
+		baseWidth = 7
+		baseHeight = 7
+		widthMultiplier = 3
+		heightMultiplier = 4
 	case LineArrowhead:
 		widthMultiplier = 5
 		heightMultiplier = 8