From c5c07332c8262e81e44993b03fae49c6cf83115c Mon Sep 17 00:00:00 2001
From: Martin Davis <mtnclimb@gmail.com>
Date: Tue, 12 Sep 2023 11:39:14 -0700
Subject: [PATCH] Add SnapToGrid test case

---
 src/geom/PrecisionModel.cpp                   |  4 ++++
 src/operation/overlayng/OverlayLabeller.cpp   |  2 ++
 tests/unit/capi/GEOSGeom_setPrecisionTest.cpp | 12 +++++++++++-
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/geom/PrecisionModel.cpp b/src/geom/PrecisionModel.cpp
index 71af03a2e0..23bf41ad4b 100644
--- a/src/geom/PrecisionModel.cpp
+++ b/src/geom/PrecisionModel.cpp
@@ -27,6 +27,7 @@
 #include <string>
 #include <cmath>
 #include <iostream>
+#include <iomanip> 
 
 #ifndef GEOS_DEBUG
 #define GEOS_DEBUG 0
@@ -50,6 +51,7 @@ PrecisionModel::makePrecise(double val) const
     std::cerr << "PrecisionModel[" << this << "]::makePrecise called" << std::endl;
 #endif
 
+//std::cout << std::setprecision(17) << val << " ==> ";
     if(modelType == FLOATING_SINGLE) {
         float floatSingleVal = static_cast<float>(val);
         return static_cast<double>(floatSingleVal);
@@ -59,6 +61,8 @@ PrecisionModel::makePrecise(double val) const
             return util::round(val / gridSize) * gridSize;
         }
         else {
+//            double v2 = util::round(val * scale) / scale;
+//std::cout << std::setprecision(17) << v2 << std::endl;
             return util::round(val * scale) / scale;
         }
     }
diff --git a/src/operation/overlayng/OverlayLabeller.cpp b/src/operation/overlayng/OverlayLabeller.cpp
index 478f26e7ed..f9c708d8d9 100644
--- a/src/operation/overlayng/OverlayLabeller.cpp
+++ b/src/operation/overlayng/OverlayLabeller.cpp
@@ -23,6 +23,7 @@
 #include <geos/util/TopologyException.h>
 
 #include <sstream>
+#include <iomanip> 
 
 
 namespace geos {      // geos
@@ -331,6 +332,7 @@ OverlayLabeller::markResultAreaEdges(int overlayOpCode)
 void
 OverlayLabeller::markInResultArea(OverlayEdge* e, int overlayOpCode)
 {
+std::cout << std::setprecision(16) << *e << std::endl;
     const OverlayLabel* label = e->getLabel();
     if (label->isBoundaryEither() && OverlayNG::isResultOfOp(overlayOpCode,
         label->getLocationBoundaryOrLine(0, Position::RIGHT, e->isForward()),
diff --git a/tests/unit/capi/GEOSGeom_setPrecisionTest.cpp b/tests/unit/capi/GEOSGeom_setPrecisionTest.cpp
index efa4b06c50..8588642dc8 100644
--- a/tests/unit/capi/GEOSGeom_setPrecisionTest.cpp
+++ b/tests/unit/capi/GEOSGeom_setPrecisionTest.cpp
@@ -238,7 +238,17 @@ void object::test<15>()
         "LINESTRING (674169.89 198051.38, 674197.7 198065.55, 674200.36 198052.38)");
 }
 
-
+// see https://trac.osgeo.org/postgis/ticket/3929
+template<>
+template<>
+void object::test<16>()
+{
+    geom1_ = fromWKT("POINT(311.4 0)");
+    geom2_ = GEOSGeom_setPrecision(geom1_, .1, 0);
+//std::cout << toWKT(geom2_) << std::endl;
+    ensure_geometry_equals(geom2_,
+        "POINT(311.4 0)");
+}
 
 } // namespace tut