From 9573adff03470c45762f04b335b7245d112c5fc3 Mon Sep 17 00:00:00 2001
From: Vladyslav Odobesku <Vladyslav.Odobesku@tomtom.com>
Date: Wed, 9 Apr 2025 19:19:20 +0300
Subject: [PATCH] Fix corner case when clipped line ends can have very low
 simplification factor thus important parts of a line can be dropped in the
 last step of conversion to vector tile.

---
 include/mapbox/geojsonvt/clip.hpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/mapbox/geojsonvt/clip.hpp b/include/mapbox/geojsonvt/clip.hpp
index 881ef16..f57ae1b 100644
--- a/include/mapbox/geojsonvt/clip.hpp
+++ b/include/mapbox/geojsonvt/clip.hpp
@@ -195,6 +195,13 @@ class clipper {
             if (lineMetrics) slice.segEnd = lineLen;
             slices.emplace_back(std::move(slice));
         }
+        
+        for (auto& current_sice : slices) {
+            if (current_sice.size() > 2) {
+                current_sice[0].z = 1.0;
+                current_sice[current_sice.size() - 1].z = 1.0;
+            }
+        }
     }
 
     vt_linear_ring clipRing(const vt_linear_ring& ring) const {