[Freeciv-Dev] Re: remove nearest_real_pos uses (PR#1211)

[jdorje@xxxxxxxxxxxxxxxxxxxxx]

Raimar Falke wrote:

> On Mon, Jan 07, 2002 at 02:39:16AM -0800, jdorje@xxxxxxxxxxxxxxxxxxxxx wrote:
> > If this patch is applied, the only remaining nearest_real_pos use will 
> > be in map_pos_to_canvas_pos in mapview_common.  If one of these places 
> > does need to use nearest_real_pos (which seems inconceivable), a comment 
> > should be added explaining why.
> Can't nearest_real_pos then be moved into mapview_common? So nobody
> can use this "dangerous tool". However this would spread topology
> knowledge (which is also bad). What about just ignoring clicks which
> are outside the map?
nearest_real_pos contains topology information, and so should remain in 
map.[ch] (or map_topology.[ch]).  This has been the a large part of the 
point of most of my changes over recent months.
Ignoring clicks that are outside the map is quite reasonable, but will 
change the behavior of the program.  This actually does more than affect 
the centering of the mapview; it causes any unreal click to be converted 
to a real one.  This has many effects, some good but most not.  A short 
sampling:
  - Clicking on an unreal tile to center the map centers on the 
nearest_real_pos.
  - Moving the mouse over an unreal tile while in goto mode gotos to 
the nearest_real_pos.
  - Center-clicking an an unreal tile pops up the tile information for 
the nearest_real_pos.
  - Activating the city grid ('t') and shift-clicking on an unreal tile 
counts as shift-clicking on the nearest_real_pos.
These effects can be fixed by returning the realness of the position, as 
Ross has proposed, or by doing the same without calling nearest_real_pos 
(in which case we rely on it to be called on a case-by-case behavior 
later).  But not calling nearest_real_pos would change the behavior of 
_all_ mouse clicks for _all_ GUI's, which is a non-trivial change.

I agree it is reasonable to move SAFE_MAPSTEP into tilespec.c, and will 
make things safer.
jason