From 6b9c15d7f0b87bd67e7a9d8aea42e5b384176a1d Mon Sep 17 00:00:00 2001
From: omkarht <omkar@mermaidchart.com>
Date: Tue, 22 Jul 2025 16:30:21 +0530
Subject: [PATCH] added reverse arrow head types

on-behalf-of: @Mermaid-Chart <hello@mermaidchart.com>
---
 .../src/diagrams/sequence/sequenceDb.ts       |  4 ++++
 .../src/diagrams/sequence/sequenceRenderer.ts | 23 +++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/packages/mermaid/src/diagrams/sequence/sequenceDb.ts b/packages/mermaid/src/diagrams/sequence/sequenceDb.ts
index 9b5868618..0112c5352 100644
--- a/packages/mermaid/src/diagrams/sequence/sequenceDb.ts
+++ b/packages/mermaid/src/diagrams/sequence/sequenceDb.ts
@@ -66,6 +66,10 @@ const LINETYPE = {
   SOLID_BOTTOM: 42,
   STICK_TOP: 43,
   STICK_BOTTOM: 44,
+  SOLID_ARROW_TOP_REVERSE: 45,
+  SOLID_ARROW_BOTTOM_REVERSE: 46,
+  STICK_ARROW_TOP_REVERSE: 47,
+  STICK_ARROW_BOTTOM_REVERSE: 48,
 } as const;
 
 const ARROWTYPE = {
diff --git a/packages/mermaid/src/diagrams/sequence/sequenceRenderer.ts b/packages/mermaid/src/diagrams/sequence/sequenceRenderer.ts
index c0471273a..6b9ecc202 100644
--- a/packages/mermaid/src/diagrams/sequence/sequenceRenderer.ts
+++ b/packages/mermaid/src/diagrams/sequence/sequenceRenderer.ts
@@ -470,6 +470,19 @@ const drawMessage = async function (diagram, msgModel, lineStartY: number, diagO
     line.attr('marker-end', 'url(' + url + '#stickBottomArrowHead)');
   }
 
+  if (type === diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE) {
+    line.attr('marker-start', 'url(' + url + '#solidBottomArrowHead)');
+  }
+  if (type === diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE) {
+    line.attr('marker-start', 'url(' + url + '#solidTopArrowHead)');
+  }
+  if (type === diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE) {
+    line.attr('marker-start', 'url(' + url + '#stickBottomArrowHead)');
+  }
+  if (type === diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE) {
+    line.attr('marker-start', 'url(' + url + '#stickTopArrowHead)');
+  }
+
   if (type === diagObj.db.LINETYPE.SOLID || type === diagObj.db.LINETYPE.DOTTED) {
     line.attr('marker-end', 'url(' + url + '#arrowhead)');
   }
@@ -1057,6 +1070,10 @@ export const draw = async function (_text: string, id: string, _version: string,
         diagObj.db.LINETYPE.SOLID_BOTTOM,
         diagObj.db.LINETYPE.STICK_TOP,
         diagObj.db.LINETYPE.STICK_BOTTOM,
+        diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE,
+        diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE,
+        diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE,
+        diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE,
         diagObj.db.LINETYPE.DOTTED,
         diagObj.db.LINETYPE.SOLID_CROSS,
         diagObj.db.LINETYPE.DOTTED_CROSS,
@@ -1456,6 +1473,10 @@ const buildMessageModel = function (msg, actors, diagObj) {
       diagObj.db.LINETYPE.SOLID_BOTTOM,
       diagObj.db.LINETYPE.STICK_TOP,
       diagObj.db.LINETYPE.STICK_BOTTOM,
+      diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE,
+      diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE,
+      diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE,
+      diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE,
       diagObj.db.LINETYPE.DOTTED,
       diagObj.db.LINETYPE.SOLID_CROSS,
       diagObj.db.LINETYPE.DOTTED_CROSS,
@@ -1512,6 +1533,8 @@ const buildMessageModel = function (msg, actors, diagObj) {
         diagObj.db.LINETYPE.DOTTED_OPEN,
         diagObj.db.LINETYPE.STICK_TOP,
         diagObj.db.LINETYPE.STICK_BOTTOM,
+        diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE,
+        diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE,
       ].includes(msg.type)
     ) {
       stopx += adjustValue(3);