[Freeciv-Dev] (PR#4718) topology cleanup for client autocenter code

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

The code for centering the mapview when the client first connects has 
lots of fallbacks.

Currently the second-to-last fallback is to iterate outwards around the 
center position on the map to find any known tile, and center on that.

The last fallback is just to center the mapview on the center tile of 
the map.

The problem is (map.xsize/2, map.ysize/2) is not the center map position 
of the map under gen-topologies: it is a native position.  And 
iterate_outward can't take map.xsize/2, map.ysize/2 as its dimensions 
since these are native, not map, dimensions.

The solution is pretty easy; just use native_to_map_pos to do the 
conversion and whole_map_iterate instead of iterate_outwards.

An alternative is to have functions to return the dimensions of the map 
in map coordinates.  But these functions generally have little use and 
are best avoided IMO.

jason

Index: client/climisc.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/client/climisc.c,v
retrieving revision 1.119
diff -u -r1.119 climisc.c
--- client/climisc.c    2003/07/28 04:00:29     1.119
+++ client/climisc.c    2003/07/29 17:08:09
@@ -359,20 +359,28 @@
     assert(punit != NULL);
     center_tile_mapcanvas(punit->x, punit->y);
   } else {
-    /* Just any known tile will do; search near the middle first. */
-    iterate_outward(map.xsize / 2, map.ysize / 2,
-                   MAX(map.xsize / 2, map.ysize / 2), x, y) {
+    int map_x, map_y, center_map_x, center_map_y, dist = -1;
+
+    /* Find the center position on the map. */
+    native_to_map_pos(&map_x, &map_y, map.xsize / 2, map.ysize / 2);
+    center_map_x = map_x;
+    center_map_y = map_y;
+
+    /* Look for any known tile - preferably close to the map center.  The
+     * default is the map center. */
+    whole_map_iterate(x, y) {
       if (tile_get_known(x, y) != TILE_UNKNOWN) {
-       center_tile_mapcanvas(x, y);
-       goto OUT;
+       int mydist = sq_map_distance(x, y, center_map_x, center_map_y);
+
+       if (dist == -1 || mydist < dist) {
+         dist = mydist;
+         map_x = x;
+         map_y = y;
+       }
       }
-    }
-    iterate_outward_end;
-    /* If we get here we didn't find a known tile.
-       Refresh a random place to clear the intro gfx. */
-    center_tile_mapcanvas(map.xsize / 2, map.ysize / 2);
-  OUT:
-    ;                          /* do nothing */
+    } whole_map_iterate_end;
+
+    center_tile_mapcanvas(map_x, map_y);
   }
 }