From 58245aecd9d7eca10f75ecbace8544bef44ecf27 Mon Sep 17 00:00:00 2001
From: mikamikasuki <211269698+mikamikasuki@users.noreply.github.com>
Date: Fri, 2 Oct 2026 05:54:59 -0700
Subject: [PATCH] Align right join tolerance with left joins

---
 CPP/Clipper2Lib/src/clipper.engine.cpp |  2 +-
 CPP/Tests/TestPolygons.cpp             | 26 +++++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/CPP/Clipper2Lib/src/clipper.engine.cpp b/CPP/Clipper2Lib/src/clipper.engine.cpp
index 6442c96ad..9578457a5 100644
--- a/CPP/Clipper2Lib/src/clipper.engine.cpp
+++ b/CPP/Clipper2Lib/src/clipper.engine.cpp
@@ -2839,7 +2839,7 @@ namespace Clipper2Lib {
 
     if (check_curr_x)
     {
-      if (PerpendicDistFromLineSqrd(pt, next->bot, next->top) > 0.35) return;
+      if (PerpendicDistFromLineSqrd(pt, next->bot, next->top) > 0.25) return;
     }
     else if (e.curr_x != next->curr_x) return;
     if (!IsCollinear(e.top, pt, next->top)) return;
diff --git a/CPP/Tests/TestPolygons.cpp b/CPP/Tests/TestPolygons.cpp
index 4894ff7fb..3d5fee3c9 100644
--- a/CPP/Tests/TestPolygons.cpp
+++ b/CPP/Tests/TestPolygons.cpp
@@ -1,3 +1,4 @@
+#include <algorithm>
 #include <gtest/gtest.h>
 #include "clipper2/clipper.h"
 #include "ClipFileLoad.h"
@@ -109,6 +110,29 @@ TEST(Clipper2Tests, TestHorzSpikes) //#720
   EXPECT_GE(paths.size(), 1);
 }
 
+TEST(Clipper2Tests, TestIssue1111PreservesNearPancakeVertex)
+{
+  using namespace Clipper2Lib;
+  Path64 path = {
+    Point64(10000000, 3), Point64(0, 2), Point64(1000000, -3229328),
+    Point64(0, 0), Point64(-20000000, 3), Point64(-20000000, -70000000),
+    Point64(10000000, -70000000)
+  };
+
+  Clipper64 clipper;
+  clipper.AddSubject({ path });
+  Paths64 solution;
+  ASSERT_TRUE(clipper.Execute(ClipType::Union, FillRule::Positive, solution));
+
+  const bool contains_moving_vertex = std::any_of(solution.begin(), solution.end(),
+    [](const Path64& polygon)
+    {
+      return std::any_of(polygon.begin(), polygon.end(), [](const Point64& point)
+        { return point.x == 1000000 && point.y == -3229328; });
+    });
+  EXPECT_TRUE(contains_moving_vertex);
+}
+
 TEST(Clipper2Tests, TestCollinearOnMacOs) //#777
 {
   Clipper2Lib::Paths64 subject;
@@ -122,4 +146,4 @@ TEST(Clipper2Tests, TestCollinearOnMacOs) //#777
   ASSERT_EQ(solution.size(), 1);
   EXPECT_EQ(solution[0].size(), 3);
   EXPECT_EQ(IsPositive(subject[0]), IsPositive(solution[0]));
-}
\ No newline at end of file
+}