[Freeciv-Dev] Re: unification of tile_visible_mapcanvas

[Jason Dorje Short <vze49r5w@xxxxxxxxxxx>]

bursig@xxxxxxxxx wrote:
> Hi again :)
>
> I repeat my ask this time about tile_visible_mapcanvas(...).
> Leave it on gui side. I don't use get_canvas_xy and freeciv common position 
> system.
There is no real "freeciv common position system".  The 
recently-introduced get_mapview_dimensions is a first step toward such a 
system, though.  All you have to do is implement that function and all 
of these features should work.
> This concern : center_tile_mapcanvas(int col, int row),
>                get_center_tile_mapcanvas(int *pCol, int *pRow),
>                tile_visible_mapcanvas(int col, int row),
>                tile_visible_and_not_on_border_mapcanvas(int col, int row),
>                etc.
This just isn't good :-(.

The general issue is that if gui-SDL differs from all of the other 
clients, it will be much harder to maintain it.
Specifically, gen-topologies will require significant changes in the 
GUI.  To support iso-rectangular maps (like what Civ2 uses) requires 
changes in a whole host of places.  If you implement custom code for 
each of these functions, that makes it _much_ harder to make the 
necessary changes.
Another example is that it takes a lot more work for you to write custom 
code to do the same things the common code does.  For instance, your 
get_mcell_xy is the equivalent of get_map_xy - but it hard-codes a 64x32 
isometric tileset.  All you get in return is a slight speed boost.  This 
is not a good tradeoff.
If you get a chance, you should jump onto IRC - #freeciv on 
irc.openprojects.net - to discuss these issues and how they may be 
resolved for the SDL client.
jason