Fix OffsetCurve EndCap parameter handling (#899)

libgeos · May 8, 2023 · afbcf67 · afbcf67
1 parent 711b540
commit afbcf67
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Showing 3 changed files with 20 additions and 3 deletions.
diff --git a/capi/geos_ts_c.cpp b/capi/geos_ts_c.cpp
@@ -1179,7 +1179,7 @@ extern "C" {
     {
         return execute(extHandle, [&]() {
             BufferParameters bp;
-            bp.setEndCapStyle(BufferParameters::CAP_FLAT);
+            //-- use default cap style ROUND 
             bp.setQuadrantSegments(quadsegs);
 
             if(joinStyle > BufferParameters::JOIN_BEVEL) {

diff --git a/include/geos/operation/buffer/OffsetCurve.h b/include/geos/operation/buffer/OffsetCurve.h
@@ -223,13 +223,16 @@ class GEOS_DLL OffsetCurve {
     OffsetCurve(const Geometry& geom, double dist, BufferParameters& bp)
         : inputGeom(geom)
         , distance(dist)
-        , bufferParams(bp)
         , matchDistance(std::abs(dist)/MATCH_DISTANCE_FACTOR)
         , geomFactory(geom.getFactory())
         {
             if (!std::isfinite(dist)) {
                 throw util::IllegalArgumentException("OffsetCurve distance must be a finite value");
             }
+            //-- set buffer params, leaving cap style as the default CAP_ROUND
+            bufferParams.setQuadrantSegments( bp.getQuadrantSegments());
+            bufferParams.setJoinStyle( bp.getJoinStyle());
+            bufferParams.setMitreLimit( bp.getMitreLimit());
         };
 
     /**

diff --git a/tests/unit/capi/GEOSOffsetCurveTest.cpp b/tests/unit/capi/GEOSOffsetCurveTest.cpp
@@ -132,7 +132,7 @@ void object::test<5>()
         "LINESTRING(33282908 6005055,33282900 6005050,33282892 6005042,33282876 6005007,33282863 6004982,33282866 6004971,33282876 6004975,33282967 6005018,33282999 6005031)",
         // Old algorithm
         // "LINESTRING EMPTY",
-        "LINESTRING (33282915.823395286 6005042.482567544, 33282948.754269265 6005058.043310193, 33282949.87329309 6005058.534544426, 33282982.439409934 6005071.764529393)",
+        "LINESTRING (33282939.63869393 6005053.735950421, 33282948.754269257 6005058.043310191, 33282949.873293087 6005058.534544423, 33282982.439409934 6005071.764529393)",
         44, 1, GEOSBUF_JOIN_MITRE, 1,
         0.000001
         );
@@ -246,5 +246,19 @@ void object::test<11>()
         );
 }
 
+// Test negative offset
+// See https://github.com/libgeos/geos/issues/897
+template<>
+template<>
+void object::test<12>()
+{
+    checkOffset(
+        "LINESTRING (292671.05 7336734.42, 292624.85 7336739.72, 292623.53 7336739.92, 292622.36 7336740.2, 292621.35 7336740.57, 292620.94 7336740.78, 292620.61 7336740.97, 292620.33 7336741.14, 292620.13 7336741.29, 292619.79 7336741.57, 292619.48 7336741.86, 292619.34 7336742.01, 292619.21 7336742.17, 292619.09 7336742.34, 292618.98 7336742.51, 292618.8 7336742.88, 292618.63 7336743.25, 292618.57 7336743.43, 292618.52 7336743.58, 292618.48 7336743.71, 292618.46 7336743.8, 292618.44 7336743.98, 292618.42 7336744.15, 292618.41 7336744.33, 292618.4 7336744.51, 292618.39 7336744.69, 292618.38 7336744.88, 292618.38 7336744.91, 292618.38 7336744.95, 292618.38 7336744.99, 292618.38 7336745.02, 292618.38 7336745.06, 292618.38 7336745.1, 292618.38 7336745.13, 292618.38 7336745.17, 292618.38 7336745.21, 292618.38 7336745.25, 292618.38 7336745.43, 292618.41 7336746.92)",
+        "LINESTRING (292672.7595667329 7336749.322260955, 292631.53009245027 7336754.052049131)",
+        -15, 8, GEOSBUF_JOIN_ROUND, 0,
+        0.000001
+        );
+}
+
 } // namespace tut