From b1cb08027e3ec33936552dbfc55db63ee0fbd8f6 Mon Sep 17 00:00:00 2001
From: Gavin Nishizawa <gavin@terrastruct.com>
Date: Fri, 14 Jul 2023 13:24:00 -0700
Subject: [PATCH] update tracing to label box

---
 d2graph/layout.go | 11 +++++++++++
 lib/geo/box.go    |  5 +++++
 2 files changed, 16 insertions(+)

diff --git a/d2graph/layout.go b/d2graph/layout.go
index 05ef65fb0..358a95934 100644
--- a/d2graph/layout.go
+++ b/d2graph/layout.go
@@ -336,6 +336,12 @@ func (edge *Edge) TraceToShape(points []*geo.Point, startIndex, endIndex int) (n
 			// add left/right padding to box
 			labelBox.TopLeft.X -= label.PADDING
 			labelBox.Width += 2 * label.PADDING
+
+			for labelBox.Contains(startingSegment.End) && startIndex+1 > endIndex {
+				startingSegment.Start = startingSegment.End
+				startingSegment.End = points[startIndex+2]
+				startIndex++
+			}
 			if intersections := labelBox.Intersections(startingSegment); len(intersections) > 0 {
 				overlapsOutsideLabel = true
 				p := intersections[0]
@@ -381,6 +387,11 @@ func (edge *Edge) TraceToShape(points []*geo.Point, startIndex, endIndex int) (n
 			// add left/right padding to box
 			labelBox.TopLeft.X -= label.PADDING
 			labelBox.Width += 2 * label.PADDING
+			for labelBox.Contains(endingSegment.Start) && endIndex-1 > startIndex {
+				endingSegment.End = endingSegment.Start
+				endingSegment.Start = points[endIndex-2]
+				endIndex--
+			}
 			if intersections := labelBox.Intersections(endingSegment); len(intersections) > 0 {
 				overlapsOutsideLabel = true
 				p := intersections[0]
diff --git a/lib/geo/box.go b/lib/geo/box.go
index 3fe0eb7c2..de9b36cff 100644
--- a/lib/geo/box.go
+++ b/lib/geo/box.go
@@ -78,3 +78,8 @@ func (b *Box) ToString() string {
 	}
 	return fmt.Sprintf("{TopLeft: %s, Width: %.0f, Height: %.0f}", b.TopLeft.ToString(), b.Width, b.Height)
 }
+
+func (b *Box) Contains(p *Point) bool {
+	return !(p.X < b.TopLeft.X || b.TopLeft.X+b.Width < p.X ||
+		p.Y < b.TopLeft.Y || b.TopLeft.Y+b.Height < p.Y)
+}