+ * Draw the grid lines.
+ */
+ draw_line(dr, BORDER + x*TILE_SIZE, BORDER + y*TILE_SIZE,
+ BORDER + (x+1)*TILE_SIZE, BORDER + y*TILE_SIZE, COL_GRID);
+ draw_line(dr, BORDER + x*TILE_SIZE, BORDER + y*TILE_SIZE,
+ BORDER + x*TILE_SIZE, BORDER + (y+1)*TILE_SIZE, COL_GRID);
+
+ /*