St_AsMVTGeom: Avoid type changes due to validation

References #4181
Closes https://github.com/postgis/postgis/pull/304/

git-svn-id: http://svn.osgeo.org/postgis/trunk@16831 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/NEWS b/NEWS
index aac36ed56dca62db80171942f3fb9d10ad9f4b07..9cc164ffd18bf5e990b43bc6e9ab4f298f946c67 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,7 @@ PostGIS 3.0.0
   - #4176, ST_Intersects supports GEOMETRYCOLLECTION (Darafei Praliaskouski)
   - #4177, Postgres 12 disallows variable length arrays in C (Laurenz Albe)
   - #4160, Use qualified names in topology extension install (Raúl Marín)
+  - #4181, St_AsMVTGeom: Avoid type changes due to validation (Raúl Marín)
 
 PostGIS 2.5.0rc1
 2018/08/19

diff --git a/postgis/mvt.c b/postgis/mvt.c
index 9ebc61882fd7e605b9d930e9cd6c79a303b04fa5..8468b05a76444e71a1737b047d39ebeea25f2b50 100644 (file)
--- a/postgis/mvt.c
+++ b/postgis/mvt.c
@@ -921,14 +921,24 @@ LWGEOM *mvt_geom(LWGEOM *lwgeom, const GBOX *gbox, uint32_t extent, uint32_t buf
        if (lwgeom == NULL || lwgeom_is_empty(lwgeom))
                return NULL;
 
-       /* if polygon(s) make valid and force clockwise as per MVT spec */
+
        if (lwgeom->type == POLYGONTYPE ||
                lwgeom->type == MULTIPOLYGONTYPE ||
                lwgeom->type == COLLECTIONTYPE)
        {
+               /* Force validation as per MVT spec */
                lwgeom = lwgeom_make_valid(lwgeom);
-               /* In image coordinates CW actually comes out a CCW, so */
-               /* we also reverse. ¯\_(ツ)_/¯ */
+
+               /* Drop type changes tp play nice with MVT renderers */
+               if (!(lwgeom->type == POLYGONTYPE ||
+                       lwgeom->type == MULTIPOLYGONTYPE ||
+                       lwgeom->type == COLLECTIONTYPE))
+               {
+                       lwgeom_free(lwgeom);
+                       return NULL;
+               }
+
+               /* In image coordinates CW actually comes out a CCW, so we reverse */
                lwgeom_force_clockwise(lwgeom);
                lwgeom_reverse_in_place(lwgeom);
        }

diff --git a/regress/mvt.sql b/regress/mvt.sql
index 7b9b4e222cdc823f4efbba8fb9c0dee3a4b9cce1..dcc237a79bc724eb136220e25f3257b62b6e73b1 100644 (file)
--- a/regress/mvt.sql
+++ b/regress/mvt.sql
@@ -257,6 +257,14 @@ SELECT 'PG43 - OFF', ST_AsText(ST_AsMVTGeom(
        ST_MakeBox2D(ST_Point(0, 0), ST_Point(100, 100)),
        10, 0, false));
 
+-- Geometry type change
+SELECT 'PG44', ST_AsEWKT(ST_AsMVTGeom(
+       'SRID=3857;MULTIPOLYGON(((-8238038.43842083 4974073.00356281,-8238058.59985694 4974035.91194892,-8238046.74211362 4974077.68076013,-8238038.43842083 4974073.00356281)))'::geometry,
+       'SRID=3857;POLYGON((-8242969.13027341 4975133.29702555,-8242969.13027341 4970241.3272153,-8238077.16046316 4970241.3272153,-8238077.16046316 4975133.29702555,-8242969.13027341 4975133.29702555))'::geometry,
+       4096,
+       16,
+       true));
+
 -- geometry encoding tests
 SELECT 'TG1', encode(ST_AsMVT(q, 'test', 4096, 'geom'), 'base64') FROM (SELECT 1 AS c1,
        ST_AsMVTGeom(ST_GeomFromText('POINT(25 17)'),
@@ -485,4 +493,4 @@ SELECT 'FI9', encode(ST_AsMVT(q, 'test', 4096, 'geom', 'c1'), 'base64') FROM (
        SELECT 1::double precision AS c1, 'abcd'::text AS c2, 20::integer as c1,
        ST_AsMVTGeom(ST_GeomFromText('POINT(25 17)'),
                ST_MakeBox2D(ST_Point(0, 0), ST_Point(4096, 4096)), 4096, 0, false) AS geom
-) AS q;
\ No newline at end of file
+) AS q;

diff --git a/regress/mvt_expected b/regress/mvt_expected
index 75b6cb95d9b80f16ef929777e301ce35e8d23657..6b711466b7fcbb62e2b6c3cb991f683de66eae85 100644 (file)
--- a/regress/mvt_expected
+++ b/regress/mvt_expected
@@ -46,6 +46,7 @@ PG42 - ON |LINESTRING(0 10,0 0,1 0)
 PG42 - OFF|LINESTRING(0 10,0 0,1 0)
 PG43 - ON |MULTIPOLYGON(((5 5,0 0,10 0,5 5)),((0 10,5 5,10 10,0 10)))
 PG43 - OFF|MULTIPOLYGON(((5 5,-1 -1,11 -1,5 5)),((5 5,11 11,-1 11,5 5)))
+PG44|
 TG1|GiEKBHRlc3QSDBICAAAYASIECTLePxoCYzEiAigBKIAgeAI=
 TG2|GiMKBHRlc3QSDhICAAAYASIGETLePwIBGgJjMSICKAEogCB4Ag==
 TG3|GiYKBHRlc3QSERICAAAYAiIJCQCAQArQD88PGgJjMSICKAEogCB4Ag==