Merge pull request #1243 from gavin-ts/arrowhead-refactor

Arrowhead refactor

d2exporter/export.go

@@ -200,15 +200,9 @@ func toConnection(edge *d2graph.Edge, theme *d2themes.Theme) d2target.Connection
 	text := edge.Text()
 
 	if edge.SrcArrow {
-		connection.SrcArrow = d2target.TriangleArrowhead
+		connection.SrcArrow = d2target.DefaultArrowhead
-		if edge.SrcArrowhead != nil {
+		if edge.SrcArrowhead != nil && edge.SrcArrowhead.Shape.Value != "" {
-			if edge.SrcArrowhead.Shape.Value != "" {
+			connection.SrcArrow = edge.SrcArrowhead.ToArrowhead()
-				filled := false
-				if edge.SrcArrowhead.Style.Filled != nil {
-					filled, _ = strconv.ParseBool(edge.SrcArrowhead.Style.Filled.Value)
-				}
-				connection.SrcArrow = d2target.ToArrowhead(edge.SrcArrowhead.Shape.Value, filled)
-			}
 		}
 	}
 	if edge.SrcArrowhead != nil {
@@ -221,15 +215,9 @@ func toConnection(edge *d2graph.Edge, theme *d2themes.Theme) d2target.Connection
 		}
 	}
 	if edge.DstArrow {
-		connection.DstArrow = d2target.TriangleArrowhead
+		connection.DstArrow = d2target.DefaultArrowhead
-		if edge.DstArrowhead != nil {
+		if edge.DstArrowhead != nil && edge.DstArrowhead.Shape.Value != "" {
-			if edge.DstArrowhead.Shape.Value != "" {
+			connection.DstArrow = edge.DstArrowhead.ToArrowhead()
-				filled := false
-				if edge.DstArrowhead.Style.Filled != nil {
-					filled, _ = strconv.ParseBool(edge.DstArrowhead.Style.Filled.Value)
-				}
-				connection.DstArrow = d2target.ToArrowhead(edge.DstArrowhead.Shape.Value, filled)
-			}
 		}
 	}
 	if edge.DstArrowhead != nil {

d2graph/d2graph.go

@@ -164,6 +164,18 @@ func (a *Attributes) ApplyTextTransform() {
 	}
 }
 
+func (a *Attributes) ToArrowhead() d2target.Arrowhead {
+	if a.Shape.Value == "" {
+		return d2target.NoArrowhead
+	}
+
+	filled := false
+	if a.Style.Filled != nil {
+		filled, _ = strconv.ParseBool(a.Style.Filled.Value)
+	}
+	return d2target.ToArrowhead(a.Shape.Value, filled)
+}
+
 // TODO references at the root scope should have their Scope set to root graph AST
 type Reference struct {
 	Key          *d2ast.KeyPath `json:"key"`

d2target/d2target.go

@@ -553,19 +553,13 @@ func (connection *Connection) GetArrowheadLabelPosition(isDst bool) *geo.Point {
 		index = len(connection.Route) - 2
 	}
 	start, end := connection.Route[index], connection.Route[index+1]
+	// Note: end to start to get normal towards unlocked top position
+	normalX, normalY := geo.GetUnitNormalVector(end.X, end.Y, start.X, start.Y)
 
-	// how much to move the label back from the very end of the edge
+	// determine how much to move the label back from the very end of the edge
-	var shift float64
+	// e.g. if normal points up {x: 0, y:1}, shift width/2 + padding to fit
-	if start.Y == end.Y {
+	shift := math.Abs(normalX)*(height/2.+label.PADDING) +
-		// shift left/right to fit on horizontal segment
+		math.Abs(normalY)*(width/2.+label.PADDING)
-		shift = width/2. + label.PADDING
-	} else if start.X == end.X {
-		// shift up/down to fit on vertical segment
-		shift = height/2. + label.PADDING
-	} else {
-		// TODO compute amount to shift according to angle instead of max
-		shift = math.Max(width, height)
-	}
 
 	length := geo.Route(connection.Route).Length()
 	var position float64
@@ -583,7 +577,7 @@ func (connection *Connection) GetArrowheadLabelPosition(isDst bool) *geo.Point {
 
 	strokeWidth := float64(connection.StrokeWidth)
 
-	labelTL, index := label.UnlockedTop.GetPointOnRoute(connection.Route, strokeWidth, position, width, height)
+	labelTL, _ := label.UnlockedTop.GetPointOnRoute(connection.Route, strokeWidth, position, width, height)
 
 	var arrowSize float64
 	if isDst && connection.DstArrow != NoArrowhead {
@@ -597,9 +591,6 @@ func (connection *Connection) GetArrowheadLabelPosition(isDst bool) *geo.Point {
 		// labelTL already accounts for strokeWidth and padding, we only want to shift further if the arrow is larger than this
 		offset := (arrowSize/2 + ARROWHEAD_PADDING) - strokeWidth/2 - label.PADDING
 		if offset > 0 {
-			start, end = connection.Route[index], connection.Route[index+1]
-			// Note: end to start to get normal towards unlocked top position
-			normalX, normalY := geo.GetUnitNormalVector(end.X, end.Y, start.X, start.Y)
 			labelTL.X += normalX * offset
 			labelTL.Y += normalY * offset
 		}
@@ -635,6 +626,8 @@ const (
 	CfMany         Arrowhead = "cf-many"
 	CfOneRequired  Arrowhead = "cf-one-required"
 	CfManyRequired Arrowhead = "cf-many-required"
+
+	DefaultArrowhead Arrowhead = TriangleArrowhead
 )
 
 var Arrowheads = map[string]struct{}{
@@ -663,8 +656,12 @@ func ToArrowhead(arrowheadType string, filled bool) Arrowhead {
 			return FilledCircleArrowhead
 		}
 		return CircleArrowhead
+	case string(NoArrowhead):
+		return NoArrowhead
 	case string(ArrowArrowhead):
 		return ArrowArrowhead
+	case string(TriangleArrowhead):
+		return TriangleArrowhead
 	case string(CfOne):
 		return CfOne
 	case string(CfMany):
@@ -674,7 +671,7 @@ func ToArrowhead(arrowheadType string, filled bool) Arrowhead {
 	case string(CfManyRequired):
 		return CfManyRequired
 	default:
-		return TriangleArrowhead
+		return DefaultArrowhead
 	}
 }