[Freeciv-Dev] Re: get_canvas_xy unification (PR#1054)

["Ross W. Wetmore" <rwetmore@xxxxxxxxxxxx>]

This function is better split into two functions, one a map to gui/canvas
coordinates, and the second a scaling/clipping of the canvas coordinates.

There is a minor bug in the map (pre-)normalization step.

Cheers,
RossW
=====

At 07:14 PM 01/11/04 -0800, jdorje@xxxxxxxxxxxxxxxxxxxxx wrote:
>The attached patch makes a new common function, base_get_canvas_xy,
>which is called by get_canvas_xy for each GUI platform.
>
>There are several advantages to this: it reduces overall code,
>consolidates places where changes will have to be made in the GUI, and
>provides isometric-view capabilities to this function for all GUI's.
>
>get_canvas_xy is kept around because the variables needed by
>base_get_canvas_xy are not common.  But they should be.  I would propose
>a naming system that is a cross between the win32 and gtk current
>systems: map_view_x0/map_view_y0 for the top-left window corner,
>map_win_width/map_win_height for the canvas width and height.  Currently
>map_canvas_store_twidth/map_canvas_store_theight are used for the canvas
>width in tiles; these are misnamed but I'm not sure what would be better
>(map_win_twidth/map_win_theight, perhaps?).  This patch is a big step
>toward an eventual total unification.
>
>Platforms tested: gtk
>Untested: xaw (I'll test shortly), win32, mui
>Unaffected: beos
>
>jason? rc
>? diff
>? old
>? topology
>Index: client/mapview_common.c
>===================================================================
>RCS file: /home/freeciv/CVS/freeciv/client/mapview_common.c,v
>retrieving revision 1.1
>diff -u -r1.1 mapview_common.c
>--- client/mapview_common.c    2001/10/30 12:11:43     1.1
>+++ client/mapview_common.c    2001/11/05 03:04:10
>@@ -21,6 +21,7 @@
> #include "mapview_g.h"
> 
> #include "mapview_common.h"
>+#include "tilespec.h"
> 
> /**************************************************************************
>  Refreshes a single tile on the map canvas.
>@@ -77,5 +78,67 @@
>     return COLOR_STD_RED;
>   } else {
>     return COLOR_STD_WHITE;
>+  }
>+}
>+
>+int base_get_canvas_xy(int map_x, int map_y,
>+                     int *canvas_x, int *canvas_y,
>+                     int map_view_x0, int map_view_y0,
>+                     int canvas_width, int canvas_height)
>+{
>+  if (is_isometric) {
>+    /* canvas_x,canvas_y is the top corner of the actual tile, not the
pixmap.
>+       This function also handles non-adjusted tile coords (like -1, -2)
as if
>+       they were adjusted.  You might want to first take a look at the
simpler
>+       city_get_canvas() for basic understanding. */
>+    int diff_xy;
>+    int diff_x, diff_y;
>+
>+    map_x %= map.xsize;

I believe you want to insure this value is in the range [0:xsize-1].

If you are passing normal coordinates, you don't need this. If you are
not it should be corrected.