From 84d8026a9b6e340b9e7a0816246020c9e997a6aa Mon Sep 17 00:00:00 2001
From: Symmetricity <184246+Symmetricity@users.noreply.github.com>
Date: Wed, 13 May 2026 20:29:57 +0200
Subject: [PATCH] Handle open way centroids as lines

LayerAsCentroid defaults to polylabel, but polylabel operates on polygon geometry. Open ways such as barriers and gates were being assigned into a polygon before calculating their label point, which can produce platform-dependent representative points.

Use the cached linestring directly for open ways and keep the existing polygon/polylabel path for closed ways. This keeps area labeling behavior unchanged while making open-way label placement match the geometry type being processed.
---
 src/osm_lua_processing.cpp | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/src/osm_lua_processing.cpp b/src/osm_lua_processing.cpp
index c395b902..bc5271a4 100644
--- a/src/osm_lua_processing.cpp
+++ b/src/osm_lua_processing.cpp
@@ -862,14 +862,25 @@ Point OsmLuaProcessing::calculateCentroid(CentroidAlgorithm algorithm) {
 		}
 		return Point(centroid.x()*10000000.0, centroid.y()*10000000.0);
 	} else if (isWay) {
-		Polygon p;
-		geom::assign_points(p, linestringCached());
-
-		if (algorithm == CentroidAlgorithm::Polylabel) {
-			// CONSIDER: pick precision intelligently
-			centroid = mapbox::polylabel(p);
+		if (!isClosed) {
+			const Linestring &ls = linestringCached();
+			if (ls.empty())
+				throw geom::centroid_exception();
+			if (ls.size()==1) {
+				centroid = ls.front();
+			} else {
+				geom::centroid(ls, centroid);
+			}
 		} else {
-			geom::centroid(p, centroid);
+			Polygon p;
+			geom::assign_points(p, linestringCached());
+
+			if (algorithm == CentroidAlgorithm::Polylabel) {
+				// CONSIDER: pick precision intelligently
+				centroid = mapbox::polylabel(p);
+			} else {
+				geom::centroid(p, centroid);
+			}
 		}
 		return Point(centroid.x()*10000000.0, centroid.y()*10000000.0);
 	} else {