connection arrowhead font color

ci/release/changelogs/next.md

@@ -6,6 +6,7 @@
 
 - Latex now includes Mathjax's ASM extension for more powerful Latex functionality [#1544](https://github.com/terrastruct/d2/pull/1544)
 - `font-color` works on Markdown [#1546](https://github.com/terrastruct/d2/pull/1546)
+- `font-color` works on arrowheads [#1582](https://github.com/terrastruct/d2/pull/1582)
 
 #### Bugfixes ⛑️
 

d2exporter/export.go

@@ -213,6 +213,9 @@ func toConnection(edge *d2graph.Edge, theme *d2themes.Theme) d2target.Connection
 				LabelWidth:  edge.SrcArrowhead.LabelDimensions.Width,
 				LabelHeight: edge.SrcArrowhead.LabelDimensions.Height,
 			}
+			if edge.SrcArrowhead.Style.FontColor != nil {
+				connection.SrcLabel.Color = edge.SrcArrowhead.Style.FontColor.Value
+			}
 		}
 	}
 	if edge.DstArrow {
@@ -228,6 +231,9 @@ func toConnection(edge *d2graph.Edge, theme *d2themes.Theme) d2target.Connection
 				LabelWidth:  edge.DstArrowhead.LabelDimensions.Width,
 				LabelHeight: edge.DstArrowhead.LabelDimensions.Height,
 			}
+			if edge.DstArrowhead.Style.FontColor != nil {
+				connection.DstLabel.Color = edge.DstArrowhead.Style.FontColor.Value
+			}
 		}
 	}
 	if theme != nil && theme.SpecialRules.NoCornerRadius {

d2renderers/d2svg/d2svg.go

@@ -613,6 +613,15 @@ func renderArrowheadLabel(connection d2target.Connection, text string, isDst boo
 	textEl.X = baselineCenter.X
 	textEl.Y = baselineCenter.Y
 	textEl.Fill = d2target.FG_COLOR
+	if isDst {
+		if connection.DstLabel.Color != "" {
+			textEl.Fill = connection.DstLabel.Color
+		}
+	} else {
+		if connection.SrcLabel.Color != "" {
+			textEl.Fill = connection.SrcLabel.Color
+		}
+	}
 	textEl.ClassName = "text-italic"
 	textEl.Style = fmt.Sprintf("text-anchor:middle;font-size:%vpx", connection.FontSize)
 	textEl.Content = RenderText(text, textEl.X, height)

e2etests/regression_test.go

@@ -1038,6 +1038,7 @@ cf many required: {
 		loadFromFile(t, "icons_on_top"),
 		loadFromFile(t, "dagre_disconnected_edge"),
 		loadFromFile(t, "outside_grid_label_position"),
+		loadFromFile(t, "arrowhead_font_color"),
 	}
 
 	runa(t, tcs)

e2etests/testdata/files/arrowhead_font_color.d2

@@ -0,0 +1,9 @@
+direction: right
+x <-> y: {
+  source-arrowhead: eth1 {
+    style.font-color: green
+  }
+  target-arrowhead: eth2 {
+    style.font-color: red
+  }
+}