[postgis-tickets] r16608 - Unify geometry centroid functions

[Darafei]

Author: komzpa
Date: 2018-06-05 07:40:45 -0700 (Tue, 05 Jun 2018)
New Revision: 16608

Modified:
   trunk/NEWS
   trunk/postgis/lwgeom_geos.c
   trunk/postgis/postgis.sql.in
Log:
Unify geometry centroid functions

Make ST_Centroid call lwgeom_centroid.

Closes #3960
Closes https://github.com/postgis/postgis/pull/256



Modified: trunk/NEWS
===================================================================
--- trunk/NEWS	2018-06-05 12:28:44 UTC (rev 16607)
+++ trunk/NEWS	2018-06-05 14:40:45 UTC (rev 16608)
@@ -51,10 +51,8 @@
   - #3097, Really allow MULTILINESTRING blades in ST_Split() (Paul Ramsey)
   - #3942, geojson: Do not include private header for json-c >= 0.13 (Björn Esser)
   - #3954, ST_GeometricMedian now supports point weights (Darafei Praliaskouski)
-  - #3965, ST_ClusterKMeans used to lose some clusters on initialization
-           (Darafei Praliaskouski)
-  - #3971, ST_ClusterKMeans now uses better initial seed (Darafei Praliaskouski)
-  - #3977, ST_ClusterKMeans is now faster and simpler (Darafei Praliaskouski)
+  - #3965, #3971, #3977, #4071 ST_ClusterKMeans rewritten: better initialization,
+           faster convergence, K=2 even faster (Darafei Praliaskouski)
   - #3982, ST_AsEncodedPolyline supports LINESTRING EMPTY and MULTIPOINT EMPTY
            (Darafei Praliaskouski)
   - #3986, ST_AsText now has second argument to limit decimal digits
@@ -72,7 +70,6 @@
            robustness issues. (Darafei Praliaskouski)
   - #4025, #4032 Fixed precision issue in ST_ClosestPointOfApproach,
            ST_DistanceCPA, and ST_CPAWithin (Paul Ramsey, Darafei Praliaskouski)
-  - #4071, ST_ClusterKMeans crash on NULL/EMPTY fixed (Darafei Praliaskouski)
   - #4076, Reduce use of GEOS in topology implementation (Björn Harrtell)
   - #4080, Add external raster band index to ST_BandMetaData
   - Add Raster Tips section to Documentation for information about
@@ -79,6 +76,7 @@
     Raster behavior (e.g. Out-DB performance, maximum open files)
   - #4084: Fixed wrong code-comment regarding front/back of BOX3D (Matthias Bay)
   - #4060, #4094, PostgreSQL JIT support (Raúl Marín, Laurenz Albe)
+  - #3960, ST_Centroid now uses lwgeom_centroid (Darafei Praliaskouski)
 
 PostGIS 2.4.4
 2018/04/08

Modified: trunk/postgis/lwgeom_geos.c
===================================================================
--- trunk/postgis/lwgeom_geos.c	2018-06-05 12:28:44 UTC (rev 16607)
+++ trunk/postgis/lwgeom_geos.c	2018-06-05 14:40:45 UTC (rev 16608)
@@ -1306,69 +1306,19 @@
 Datum centroid(PG_FUNCTION_ARGS)
 {
 	GSERIALIZED *geom, *result;
-	GEOSGeometry *geosgeom, *geosresult;
-	LWGEOM *igeom = NULL, *linear_geom = NULL;
-	int32 perQuad= 16;
-	int type = 0;
+	LWGEOM *lwgeom, *lwresult;
+
 	geom = PG_GETARG_GSERIALIZED_P(0);
 
-	/* Empty.Centroid() == Point Empty */
-	if ( gserialized_is_empty(geom) )
-	{
-		LWPOINT *lwp = lwpoint_construct_empty(
-		                   gserialized_get_srid(geom),
-		                   gserialized_has_z(geom),
-		                   gserialized_has_m(geom));
-		result = geometry_serialize(lwpoint_as_lwgeom(lwp));
-		lwpoint_free(lwp);
-		PG_RETURN_POINTER(result);
-	}
+	lwgeom = lwgeom_from_gserialized(geom);
+	lwresult = lwgeom_centroid(lwgeom);
+	lwgeom_free(lwgeom);
+	PG_FREE_IF_COPY(geom, 0);
 
-	type = gserialized_get_type(geom) ;
-	/* Converting curve geometry to linestring if necessary*/
-	if(type == CIRCSTRINGTYPE || type == COMPOUNDTYPE )
-	{/* curve geometry?*/
-		igeom = lwgeom_from_gserialized(geom);
-		PG_FREE_IF_COPY(geom, 0); /*free memory, we already have a lwgeom geometry copy*/
-		linear_geom = lwgeom_stroke(igeom, perQuad);
-		lwgeom_free(igeom);
-		if (!linear_geom) PG_RETURN_NULL();
+	if (!lwresult) PG_RETURN_NULL();
 
-		geom = geometry_serialize(linear_geom);
-		lwgeom_free(linear_geom);
-	}
-
-	initGEOS(lwpgnotice, lwgeom_geos_error);
-
-	geosgeom = POSTGIS2GEOS(geom);
-
-	if (!geosgeom)
-		HANDLE_GEOS_ERROR("First argument geometry could not be converted to GEOS");
-
-	geosresult = GEOSGetCentroid(geosgeom);
-
-	if (!geosresult)
-	{
-		GEOSGeom_destroy(geosgeom);
-		HANDLE_GEOS_ERROR("GEOSGetCentroid");
-	}
-
-	GEOSSetSRID(geosresult, gserialized_get_srid(geom));
-
-	result = GEOS2POSTGIS(geosresult, gserialized_has_z(geom));
-
-	if (!result)
-	{
-		GEOSGeom_destroy(geosgeom);
-		GEOSGeom_destroy(geosresult);
-		elog(ERROR,"Error in GEOS-PGIS conversion");
-		PG_RETURN_NULL();
-	}
-	GEOSGeom_destroy(geosgeom);
-	GEOSGeom_destroy(geosresult);
-
-	PG_FREE_IF_COPY(geom, 0);
-
+	result = geometry_serialize(lwresult);
+	lwgeom_free(lwresult);
 	PG_RETURN_POINTER(result);
 }
 

Modified: trunk/postgis/postgis.sql.in
===================================================================
--- trunk/postgis/postgis.sql.in	2018-06-05 12:28:44 UTC (rev 16607)
+++ trunk/postgis/postgis.sql.in	2018-06-05 14:40:45 UTC (rev 16608)
@@ -3710,7 +3710,6 @@
 --
 --
 -- Availability: 2.1.0
--- Requires GEOS >= 3.4.0
 --
 CREATE OR REPLACE FUNCTION ST_DelaunayTriangles(g1 geometry, tolerance float8 DEFAULT 0.0, flags int4 DEFAULT 0)
        RETURNS geometry