[geos-commits] [SCM] GEOS branch master updated. 2522fba2d8851500a8d9f39337e07bbf5c0a5653

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- Log -----------------------------------------------------------------
commit 2522fba2d8851500a8d9f39337e07bbf5c0a5653
Author: Paul Ramsey <pramsey at cleverelephant.ca>
Date:   Mon Nov 30 17:34:06 2020 -0800

    Use SnapRoundingNoder in BufferOp
    This avoids doing a precision reduction on the input geometry.
    It maps more closely to the implementation in JTS.
    It still does an increasing loop of larger tolerance,
    in the event of a failure.
    This is to address the regression reported by GEOSwift
    downstream on 3.9.0beta1

diff --git a/src/operation/buffer/BufferOp.cpp b/src/operation/buffer/BufferOp.cpp
index 3e815fd..d0f1b9a 100644
--- a/src/operation/buffer/BufferOp.cpp
+++ b/src/operation/buffer/BufferOp.cpp
@@ -34,6 +34,7 @@
 
 #include <geos/noding/snapround/MCIndexSnapRounder.h>
 #include <geos/noding/snapround/MCIndexPointSnapper.h>
+#include <geos/noding/snapround/SnapRoundingNoder.h>
 
 //FIXME: for temporary use, see other FIXME in file
 #include <geos/algorithm/LineIntersector.h>
@@ -222,26 +223,37 @@ BufferOp::bufferReducedPrecision(int precisionDigits)
 void
 BufferOp::bufferFixedPrecision(const PrecisionModel& fixedPM)
 {
+    PrecisionModel pm(1.0); // fixed as well
 
+#define SNAP_WITH_NODER
+#ifdef SNAP_WITH_NODER
+    // Reduce precision using SnapRoundingNoder
+    //
+    // This more closely aligns with JTS implementation,
+    // and avoids reducing the precision of the input
+    // geometry.
+    //
+    // TODO: Add a finer fallback sequence. Full
+    //       precision, then SnappingNoder, then
+    //       SnapRoundingNoder.
 
-    PrecisionModel pm(1.0); // fixed as well
+    snapround::SnapRoundingNoder inoder(&pm);
+    ScaledNoder noder(inoder, fixedPM.getScale());
+    BufferBuilder bufBuilder(bufParams);
+    bufBuilder.setWorkingPrecisionModel(&fixedPM);
+    bufBuilder.setNoder(&noder);
+    resultGeometry = bufBuilder.buffer(argGeom, distance);
 
-#if 0 /* FIXME: MCIndexSnapRounder seems to be still bogus */
-    snapround::MCIndexSnapRounder inoder(pm);
 #else
     algorithm::LineIntersector li(&fixedPM);
     IntersectionAdder ia(li);
     MCIndexNoder inoder(&ia);
-#endif
-
     ScaledNoder noder(inoder, fixedPM.getScale());
-
     BufferBuilder bufBuilder(bufParams);
     bufBuilder.setWorkingPrecisionModel(&fixedPM);
-
     bufBuilder.setNoder(&noder);
 
-    // Reduce precision of the input geometry
+    // Snap by reducing the precision of the input geometry
     //
     // NOTE: this reduction is not in JTS and should supposedly
     //       not be needed because the PrecisionModel we pass
@@ -266,6 +278,7 @@ BufferOp::bufferFixedPrecision(const PrecisionModel& fixedPM)
 
     // this may throw an exception, if robustness errors are encountered
     resultGeometry = bufBuilder.buffer(workGeom, distance);
+#endif
 }
 
 } // namespace geos.operation.buffer
diff --git a/tests/unit/operation/buffer/BufferOpTest.cpp b/tests/unit/operation/buffer/BufferOpTest.cpp
index b2dc84f..ac05b9b 100644
--- a/tests/unit/operation/buffer/BufferOpTest.cpp
+++ b/tests/unit/operation/buffer/BufferOpTest.cpp
@@ -12,6 +12,7 @@
 #include <geos/geom/Geometry.h>
 #include <geos/algorithm/PointLocator.h>
 #include <geos/io/WKTReader.h>
+#include <geos/io/WKTWriter.h>
 #include <geos/geom/CoordinateSequence.h>
 // std
 #include <memory>
@@ -27,6 +28,7 @@ namespace tut {
 struct test_bufferop_data {
     const geos::geom::GeometryFactory& gf;
     geos::io::WKTReader wktreader;
+    geos::io::WKTWriter wktwriter;
     int const default_quadrant_segments;
 
     typedef geos::geom::Geometry::Ptr GeomPtr;
@@ -363,7 +365,7 @@ MULTILINESTRING(  \
 
     // We're basically only interested an rough sense of a
     // meaningful result.
-    ensure_equals(gBuffer->getNumPoints(), std::size_t(47));
+    ensure_equals(gBuffer->getNumPoints(), std::size_t(46));
     ensure_equals(int(gBuffer->getArea()), 3520);
 }
 
@@ -421,5 +423,29 @@ void object::test<13>
     ensure_equals(gBuffer->getGeometryTypeId(), geos::geom::GEOS_POLYGON);
 }
 
+// Test for GEOSwift regression failure
+template<>
+template<>
+void object::test<14>
+()
+{
+    using geos::operation::buffer::BufferOp;
+    using geos::operation::buffer::BufferParameters;
+
+    std::string wkt0("GEOMETRYCOLLECTION (POINT (1 2), MULTIPOINT ((1 2), (3 4)), LINESTRING (1 2, 3 4), MULTILINESTRING ((1 2, 3 4), (5 6, 7 8)), POLYGON ((2 2, -2 2, -2 -2, 2 -2, 2 2), (1 1, 1 -1, -1 -1, -1 1, 1 1)), MULTIPOLYGON (((2 2, -2 2, -2 -2, 2 -2, 2 2), (1 1, 1 -1, -1 -1, -1 1, 1 1)), ((7 2, 3 2, 3 -2, 7 -2, 7 2))))");
+
+    GeomPtr g0(wktreader.read(wkt0));
+    BufferOp op(g0.get());
+
+    double const distance = 0.5;
+    GeomPtr gBuffer(op.getResultGeometry(distance));
+
+    // std::cout << wktwriter.write(gBuffer.get()) << std::endl;
+
+    ensure_not(gBuffer->isEmpty());
+    ensure(gBuffer->isValid());
+    ensure_equals(gBuffer->getGeometryTypeId(), geos::geom::GEOS_MULTIPOLYGON);
+}
+
 } // namespace tut
 

-----------------------------------------------------------------------

Summary of changes:
 src/operation/buffer/BufferOp.cpp            | 29 ++++++++++++++++++++--------
 tests/unit/operation/buffer/BufferOpTest.cpp | 28 ++++++++++++++++++++++++++-
 2 files changed, 48 insertions(+), 9 deletions(-)


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