[Freeciv-Dev] Re: (PR#3924) Bugfix for map/canvas coordination functions

["a-l@xxxxxxx" <a-l@xxxxxxx>]

On Thu, 3 Apr 2003 08:23:25 -0800
"Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx> wrote:

> Please use the DIVIDE macro instead of manually checking for the 
> negative case.

Sorry, assembly habit. New patch is also verified.


Arnstein

--- cvs-Apr-02/client/mapview_common.c  Thu Apr  3 15:38:37 2003
+++ bugfix-map-canvas/client/mapview_common.c   Thu Apr  3 20:32:04 2003
@@ -214,7 +214,7 @@
                                    + mapview_canvas.tile_width)) {
       *canvas_x = map_x + map.xsize - mapview_canvas.map_x0;
     } else {
-      *canvas_x = -1;
+      *canvas_x = map_x - mapview_canvas.map_x0;
     }
 
     *canvas_y = map_y - mapview_canvas.map_y0;
@@ -235,6 +235,8 @@
 **************************************************************************/
 bool canvas_to_map_pos(int *map_x, int *map_y, int canvas_x, int canvas_y)
 {
+  const int W = NORMAL_TILE_WIDTH, H = NORMAL_TILE_HEIGHT;
+
   if (is_isometric) {
     /* The basic operation here is a simple pi/4 rotation; however, we
      * have to first scale because the tiles have different width and
@@ -261,13 +263,11 @@
      *
      * For another example of this math, see canvas_pos_to_city_pos().
      */
-    const int W = NORMAL_TILE_WIDTH, H = NORMAL_TILE_HEIGHT;
-
     *map_x = DIVIDE(canvas_x * H + canvas_y * W, W * H);
     *map_y = DIVIDE(canvas_y * W - canvas_x * H, W * H);
   } else {                     /* is_isometric */
-    *map_x = canvas_x / NORMAL_TILE_WIDTH;
-    *map_y = canvas_y / NORMAL_TILE_HEIGHT;
+    *map_x = DIVIDE(canvas_x, W);
+    *map_y = DIVIDE(canvas_y, H);
   }
 
   *map_x += mapview_canvas.map_x0;