Added support for the use of tile_map_edge_buffer when using WMS with…

… tiled=true vendor specific parameter (WMS-C)

This is a rebase of #5199
on top of latest main, with the addition of a test.

Comments of #5199 (comment)
have been only adressed by adding appropriate TODOs in the code.

Co-authored-by: deduikertjes <deduikertjes@xs4all.nl>

mapwms.cpp

@@ -867,6 +867,7 @@ int msWMSLoadGetMapParams(mapObj *map, int nVersion,
   const char *request = NULL;
   int status = 0;
   const char *layerlimit = NULL;
+  bool tiled = false;
 
   const char *sldenabled=NULL;
   const char *sld_url=NULL;
@@ -1172,6 +1173,10 @@ int msWMSLoadGetMapParams(mapObj *map, int nVersion,
     else if (strcasecmp(names[i], "BBOX_PIXEL_IS_POINT") == 0) {
       bbox_pixel_is_point = (strcasecmp(values[i], "TRUE") == 0);
     }
+    /* Vendor specific TILED (WMS-C) */
+    else if (strcasecmp(names[i], "TILED") == 0) {
+      tiled = (strcasecmp(values[i], "TRUE") == 0);
+    }
     /* Vendor-specific FILTER, added in RFC-118 */
     else if (strcasecmp(names[i], "FILTER") == 0) {
       filter = values[i];
@@ -1239,6 +1244,50 @@ int msWMSLoadGetMapParams(mapObj *map, int nVersion,
     adjust_extent = true;
   }
 
+  if (tiled) {
+    const char *value;
+    hashTableObj *meta = &(map->web.metadata);
+    int map_edge_buffer = 0;
+
+    if ((value = msLookupHashTable(meta, "tile_map_edge_buffer")) != NULL) {
+        map_edge_buffer = atoi(value);
+    }
+    if (map_edge_buffer > 0) {
+      /* adjust bbox and width and height to the buffer */
+      const double buffer_x = map_edge_buffer * (map->extent.maxx - map->extent.minx) / (double)map->width;
+      const double buffer_y = map_edge_buffer * (map->extent.maxy - map->extent.miny) / (double)map->height;
+
+      // TODO: we should probably clamp the extent to avoid going outside of -180,-90,180,90 for geographic CRS for example
+      map->extent.minx -= buffer_x;
+      map->extent.maxx += buffer_x;
+      map->extent.miny -= buffer_y;
+      map->extent.maxy += buffer_y;
+
+      map->width += 2 * map_edge_buffer;
+      map->height += 2 * map_edge_buffer;
+
+      if( map_edge_buffer > 0 ) {
+        char tilebufferstr[64];
+
+        /* Write the tile buffer to a string */
+        snprintf(tilebufferstr, sizeof(tilebufferstr), "-%d", map_edge_buffer);
+
+        /* Hm, the labelcache buffer is set... */
+        if((value = msLookupHashTable(meta, "labelcache_map_edge_buffer")) != NULL) {
+          /* If it's too small, replace with a bigger one */
+          if( map_edge_buffer > abs(atoi(value)) ) {
+            msRemoveHashTable(meta, "labelcache_map_edge_buffer");
+            msInsertHashTable(meta, "labelcache_map_edge_buffer", tilebufferstr);
+          }
+        }
+        /* No labelcache buffer value? Then we use the tile buffer. */
+        else {
+          msInsertHashTable(meta, "labelcache_map_edge_buffer", tilebufferstr);
+        }
+      }
+    }
+  }
+
   /*
   ** If any select layers have a default time, we will apply the default
   ** time value even if no TIME request was in the url.
@@ -3718,6 +3767,46 @@ int msWMSGetMap(mapObj *map, int nVersion, char **names, char **values, int nume
     img = msDrawMap(map, drawquerymap);
   }
 
+/* see if we have tiled = true and a buffer */
+  /* if so, clip the image */
+  for (int i=0; i<numentries; i++) {
+    if (strcasecmp(names[i], "TILED") == 0 && strcasecmp(values[i], "TRUE") == 0) {
+      hashTableObj *meta = &(map->web.metadata);
+      const char *value;
+
+      if ((value = msLookupHashTable(meta, "tile_map_edge_buffer")) != NULL) {
+        const int map_edge_buffer = atoi(value);
+        if ( map_edge_buffer > 0 ) {
+          /* we have to clip the image */
+
+          // TODO: we could probably avoid the use of an intermediate image
+          // by playing with the rasterBufferObj's data->rgb.pixels and data->rgb.row_stride values.
+          rendererVTableObj* renderer = MS_MAP_RENDERER(map);
+          rasterBufferObj imgBuffer;
+          if( renderer->getRasterBufferHandle((imageObj*)img,&imgBuffer) != MS_SUCCESS )
+          {
+              msFreeImage(img);
+              return MS_FAILURE;
+          }
+
+          int width = map->width - map_edge_buffer - map_edge_buffer;
+          int height = map->height - map_edge_buffer - map_edge_buffer;
+          imageObj* tmp = msImageCreate( width, height, map->outputformat, NULL, NULL, map->resolution, map->defresolution, NULL);
+
+          if((MS_FAILURE == renderer->mergeRasterBuffer(tmp,&imgBuffer,1.0,map_edge_buffer, map_edge_buffer,0, 0, width, height ))) {
+            msFreeImage(tmp);
+            msFreeImage(img);
+            img = NULL;
+          } else {
+            msFreeImage(img);
+            img = tmp;
+          }
+        }
+      }
+      break;
+    }
+  }
+
   if (img == NULL)
     return msWMSException(map, nVersion, NULL, wms_exception_format);
 

msautotest/wxs/wms_tiled.map

@@ -0,0 +1,80 @@
+#
+# Test WMS-C TILED=TRUE
+#
+# REQUIRES: INPUT=GDAL OUTPUT=PNG SUPPORTS=WMS
+
+# RUN_PARMS: wms_tiled_tiled_disabled.png [MAPSERV] QUERY_STRING="map=[MAPFILE]&VERSION=1.3.0&REQUEST=GetMap&CRS=EPSG%3A4326&BBOX=44.1,-65.755,47.3,-58.375&WIDTH=400&HEIGHT=400&LAYERS=popplace&STYLES=&FORMAT=image%2Fpng" > [RESULT_DEMIME]
+
+# RUN_PARMS: wms_tiled_tiled_enabled.png [MAPSERV] QUERY_STRING="map=[MAPFILE]&VERSION=1.3.0&REQUEST=GetMap&CRS=EPSG%3A4326&BBOX=44.1,-65.755,47.3,-58.375&WIDTH=400&HEIGHT=400&LAYERS=popplace&STYLES=&FORMAT=image%2Fpng&TILED=TRUE" > [RESULT_DEMIME]
+
+MAP
+
+NAME WMS_TILED
+STATUS ON
+SIZE 400 300
+UNITS DD
+IMAGECOLOR 255 255 255
+SHAPEPATH ./data
+SYMBOLSET etc/symbols.sym
+FONTSET etc/fonts.txt
+
+OUTPUTFORMAT
+  NAME GDPNG
+  DRIVER "GD/PNG"
+  MIMETYPE "image/png"
+  EXTENSION "png"
+END
+
+
+#
+# Start of web interface definition
+#
+WEB
+
+ IMAGEPATH "/tmp/ms_tmp/"
+ IMAGEURL "/ms_tmp/"
+
+  METADATA
+    "wms_title"		   "Test simple wms"
+    "wms_onlineresource"   "http://localhost/path/to/wms_simple?"
+    "wms_srs"		   "EPSG:42304 EPSG:42101 EPSG:4269 EPSG:4326"
+    "ows_schemas_location" "http://ogc.dmsolutions.ca"
+    "wms_sld_enabled"      "false"
+    "ows_enable_request" "*" 
+    "tile_map_edge_buffer" "50"
+  END
+END
+
+PROJECTION
+   "init=epsg:4326"
+END
+
+
+#
+# Start of layer definitions
+#
+
+
+LAYER
+  NAME popplace
+  DATA popplace
+  METADATA
+    "wms_title"         "popplace"
+    "wms_description"   "Cities of I.P.E."
+  END
+  TYPE POINT
+  STATUS ON
+  PROJECTION
+    "init=./data/epsg2:42304"
+  END
+  DUMP TRUE
+  CLASS
+    SYMBOL 2
+    SIZE 40
+    NAME "Cities"
+    COLOR 0 0 0
+  END
+END # Layer
+
+
+END # Map File