From 5fb770cb5784af4fd0576aafedbe4e4978f95930 Mon Sep 17 00:00:00 2001
From: Arnaud Roques <plantuml@gmail.com>
Date: Mon, 4 Oct 2021 23:01:59 +0200
Subject: [PATCH] Fix arrow constraint position

---
 .../timingdiagram/TimeConstraint.java         |  4 ++++
 .../timingdiagram/graphic/Histogram.java      | 24 ++++++++++++-------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/net/sourceforge/plantuml/timingdiagram/TimeConstraint.java b/src/net/sourceforge/plantuml/timingdiagram/TimeConstraint.java
index f44927e53..3cbdd1a93 100644
--- a/src/net/sourceforge/plantuml/timingdiagram/TimeConstraint.java
+++ b/src/net/sourceforge/plantuml/timingdiagram/TimeConstraint.java
@@ -76,6 +76,10 @@ public class TimeConstraint {
 		this.styleBuilder = skinParam.getCurrentStyleBuilder();
 	}
 
+	public final boolean containsStrict(TimeTick other) {
+		return tick1.compareTo(other) < 0 && tick2.compareTo(other) > 0;
+	}
+
 	public final TimeTick getTick1() {
 		return tick1;
 	}
diff --git a/src/net/sourceforge/plantuml/timingdiagram/graphic/Histogram.java b/src/net/sourceforge/plantuml/timingdiagram/graphic/Histogram.java
index 7b0a26283..d0e3ae801 100644
--- a/src/net/sourceforge/plantuml/timingdiagram/graphic/Histogram.java
+++ b/src/net/sourceforge/plantuml/timingdiagram/graphic/Histogram.java
@@ -347,18 +347,16 @@ public class Histogram implements PDrawing {
 
 	private void drawConstraints(UGraphic ug) {
 		for (TimeConstraint constraint : constraints) {
-			final String state1 = last(getStatesAt(constraint.getTick1()));
-			final String state2 = getStatesAt(constraint.getTick2()).get(0);
-			final double y1 = yOfState(state1);
-			final double y2 = yOfState(state2);
-			constraint.drawU(ug.apply(UTranslate.dy(y1)), ruler);
+			double y = yOfState(constraint.getTick1());
+			for (ChangeState change : changes) {
+				if (constraint.containsStrict(change.getWhen())) {
+					y = Math.min(y, yOfState(change.getWhen()));
+				}
+			}
+			constraint.drawU(ug.apply(UTranslate.dy(y)), ruler);
 		}
 	}
 
-	private static String last(List<String> list) {
-		return list.get(list.size() - 1);
-	}
-
 	private Point2D.Double getInitialPoint() {
 		return new Point2D.Double(-getInitialWidth(), yOfState(initialState));
 	}
@@ -380,6 +378,14 @@ public class Histogram implements PDrawing {
 		return stepHeight() * nb;
 	}
 
+	private double yOfState(TimeTick when) {
+		return yOfState(last(getStatesAt(when)));
+	}
+
+	private static String last(List<String> list) {
+		return list.get(list.size() - 1);
+	}
+
 	private double stepHeight() {
 		if (suggestedHeight == 0 || allStates.size() <= 1) {
 			return 20;