Add ST_MakeEnvelope() constructor, terse function for making bbox polygons. (#199)

git-svn-id: http://svn.osgeo.org/postgis/trunk@4831 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/postgis/lwgeom_functions_basic.c b/postgis/lwgeom_functions_basic.c
index eb645eece0cfbd67a88df0d71f98dd3932ec6c39..9adbdd9292e7f1680d6d7c1866b21d404e6e1b3d 100644 (file)
--- a/postgis/lwgeom_functions_basic.c
+++ b/postgis/lwgeom_functions_basic.c
@@ -77,6 +77,7 @@ Datum LWGEOM_affine(PG_FUNCTION_ARGS);
 Datum LWGEOM_longitude_shift(PG_FUNCTION_ARGS);
 Datum optimistic_overlap(PG_FUNCTION_ARGS);
 Datum ST_GeoHash(PG_FUNCTION_ARGS);
+Datum ST_MakeEnvelope(PG_FUNCTION_ARGS);
 
 void lwgeom_affine_ptarray(POINTARRAY *pa, double afac, double bfac, double cfac,
                            double dfac, double efac, double ffac, double gfac, double hfac, double ifac, double xoff, double yoff, double zoff);
@@ -2766,6 +2767,56 @@ Datum LWGEOM_same(PG_FUNCTION_ARGS)
        PG_RETURN_BOOL(result);
 }
 
+PG_FUNCTION_INFO_V1(ST_MakeEnvelope);
+Datum ST_MakeEnvelope(PG_FUNCTION_ARGS)
+{
+       LWPOLY *poly;
+       PG_LWGEOM *result;
+       POINTARRAY **pa;
+       double *pts;
+       double x1, y1, x2, y2;
+       int srid;
+
+       POSTGIS_DEBUG(2, "ST_MakeEnvelope called");
+
+       x1 = PG_GETARG_FLOAT8(0);
+       y1 = PG_GETARG_FLOAT8(1);
+       x2 = PG_GETARG_FLOAT8(2);
+       y2 = PG_GETARG_FLOAT8(3);
+       srid = PG_GETARG_INT32(4);
+
+       pa = (POINTARRAY**)palloc(sizeof(POINTARRAY*));
+       pa[0] = ptarray_construct(0, 0, 5);
+       pts = (double*)(pa[0]->serialized_pointlist); 
+
+       /* 1st point */
+       pts[0] = x1;
+       pts[1] = y1;
+
+       /* 2nd point */
+       pts[2] = x1;
+       pts[3] = y2;
+
+       /* 3rd point */
+       pts[4] = x2;
+       pts[5] = y2;
+
+       /* 4th point */
+       pts[6] = x2;
+       pts[7] = y1;
+
+       /* 5th point */
+       pts[8] = x1;
+       pts[9] = y1;
+
+       poly = lwpoly_construct(srid, ptarray_compute_box2d(pa[0]), 1, pa);
+
+       result = pglwgeom_serialize((LWGEOM*)poly);
+       lwpoly_free(poly);
+       
+       PG_RETURN_POINTER(result);
+}
+
 PG_FUNCTION_INFO_V1(LWGEOM_makepoint);
 Datum LWGEOM_makepoint(PG_FUNCTION_ARGS)
 {

diff --git a/postgis/postgis.sql.in.c b/postgis/postgis.sql.in.c
index d4e5a0ed57299544353a9196244a4a10b3e6dd87..8ec0daa01147ee06269c01fb708129fe35aad8a6 100644 (file)
--- a/postgis/postgis.sql.in.c
+++ b/postgis/postgis.sql.in.c
@@ -1815,6 +1815,11 @@ CREATE OR REPLACE FUNCTION ST_SetPoint(geometry, integer, geometry)
        AS 'MODULE_PATHNAME', 'LWGEOM_setpoint_linestring'
        LANGUAGE 'C' IMMUTABLE STRICT;
 
+-- Availability: 1.5.0
+CREATE OR REPLACE FUNCTION ST_MakeEnvelope(float8, float8, float8, float8, integer)
+       RETURNS geometry
+       AS 'MODULE_PATHNAME', 'ST_MakeEnvelope'
+       LANGUAGE 'C' IMMUTABLE STRICT;
 
 -- Deprecation in 1.2.3
 CREATE OR REPLACE FUNCTION MakePolygon(geometry, geometry[])