unfilled triangle arrowhead

d2graph/d2graph.go

@@ -181,9 +181,10 @@ func (a *Attributes) ToArrowhead() d2target.Arrowhead {
 		return d2target.NoArrowhead
 	}
 
-	filled := false
+	var filled *bool
 	if a.Style.Filled != nil {
-		filled, _ = strconv.ParseBool(a.Style.Filled.Value)
+		v, _ := strconv.ParseBool(a.Style.Filled.Value)
+		filled = go2.Pointer(v)
 	}
 	return d2target.ToArrowhead(a.Shape.Value, filled)
 }

d2renderers/d2svg/d2svg.go

@@ -138,6 +138,28 @@ func arrowheadMarker(isTarget bool, id string, connection d2target.Connection) s
 			)
 		}
 		path = polygonEl.Render()
+	case d2target.UnfilledTriangleArrowhead:
+		polygonEl := d2themes.NewThemableElement("polygon")
+		polygonEl.Fill = d2target.BG_COLOR
+		polygonEl.Stroke = connection.Stroke
+		polygonEl.ClassName = "connection"
+		polygonEl.Attributes = fmt.Sprintf(`stroke-width="%d"`, connection.StrokeWidth)
+
+		if isTarget {
+			polygonEl.Points = fmt.Sprintf("%f,%f %f,%f %f,%f",
+				0., 0.,
+				width, height/2.0,
+				0., height,
+			)
+		} else {
+			polygonEl.Points = fmt.Sprintf("%f,%f %f,%f %f,%f",
+				width, 0.,
+				0., height/2.0,
+				width, height,
+			)
+		}
+		path = polygonEl.Render()
+
 	case d2target.TriangleArrowhead:
 		polygonEl := d2themes.NewThemableElement("polygon")
 		polygonEl.Fill = connection.Stroke

d2target/d2target.go

@@ -720,13 +720,14 @@ func (c Connection) GetID() string {
 type Arrowhead string
 
 const (
-	NoArrowhead            Arrowhead = "none"
-	ArrowArrowhead         Arrowhead = "arrow"
-	TriangleArrowhead      Arrowhead = "triangle"
-	DiamondArrowhead       Arrowhead = "diamond"
-	FilledDiamondArrowhead Arrowhead = "filled-diamond"
-	CircleArrowhead        Arrowhead = "circle"
-	FilledCircleArrowhead  Arrowhead = "filled-circle"
+	NoArrowhead               Arrowhead = "none"
+	ArrowArrowhead            Arrowhead = "arrow"
+	UnfilledTriangleArrowhead Arrowhead = "unfilled-triangle"
+	TriangleArrowhead         Arrowhead = "triangle"
+	DiamondArrowhead          Arrowhead = "diamond"
+	FilledDiamondArrowhead    Arrowhead = "filled-diamond"
+	CircleArrowhead           Arrowhead = "circle"
+	FilledCircleArrowhead     Arrowhead = "filled-circle"
 
 	// For fat arrows
 	LineArrowhead Arrowhead = "line"
@@ -740,29 +741,28 @@ const (
 	DefaultArrowhead Arrowhead = TriangleArrowhead
 )
 
+// valid values for arrowhead.shape
 var Arrowheads = map[string]struct{}{
-	string(NoArrowhead):            {},
-	string(ArrowArrowhead):         {},
-	string(TriangleArrowhead):      {},
-	string(DiamondArrowhead):       {},
-	string(FilledDiamondArrowhead): {},
-	string(CircleArrowhead):        {},
-	string(FilledCircleArrowhead):  {},
-	string(CfOne):                  {},
-	string(CfMany):                 {},
-	string(CfOneRequired):          {},
-	string(CfManyRequired):         {},
+	string(NoArrowhead):       {},
+	string(ArrowArrowhead):    {},
+	string(TriangleArrowhead): {},
+	string(DiamondArrowhead):  {},
+	string(CircleArrowhead):   {},
+	string(CfOne):             {},
+	string(CfMany):            {},
+	string(CfOneRequired):     {},
+	string(CfManyRequired):    {},
 }
 
-func ToArrowhead(arrowheadType string, filled bool) Arrowhead {
+func ToArrowhead(arrowheadType string, filled *bool) Arrowhead {
 	switch arrowheadType {
 	case string(DiamondArrowhead):
-		if filled {
+		if filled != nil && *filled {
 			return FilledDiamondArrowhead
 		}
 		return DiamondArrowhead
 	case string(CircleArrowhead):
-		if filled {
+		if filled != nil && *filled {
 			return FilledCircleArrowhead
 		}
 		return CircleArrowhead
@@ -771,6 +771,9 @@ func ToArrowhead(arrowheadType string, filled bool) Arrowhead {
 	case string(ArrowArrowhead):
 		return ArrowArrowhead
 	case string(TriangleArrowhead):
+		if filled != nil && !(*filled) {
+			return UnfilledTriangleArrowhead
+		}
 		return TriangleArrowhead
 	case string(CfOne):
 		return CfOne
@@ -794,7 +797,7 @@ func (arrowhead Arrowhead) Dimensions(strokeWidth float64) (width, height float6
 		baseHeight = 4
 		widthMultiplier = 4
 		heightMultiplier = 4
-	case TriangleArrowhead:
+	case TriangleArrowhead, UnfilledTriangleArrowhead:
 		baseWidth = 4
 		baseHeight = 4
 		widthMultiplier = 3