[iagno] Factor code a bit.

[Arnaud B. <arnaudb src gnome org>]

commit 3c958b1135f9e527633fd7c454691a98a06b7953
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Wed Jun 5 15:04:07 2019 +0200

    Factor code a bit.
    
    Introduce queue_draw_tile.

 src/game-view.vala | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)
---
diff --git a/src/game-view.vala b/src/game-view.vala
index 2608021..4c56a5f 100644
--- a/src/game-view.vala
+++ b/src/game-view.vala
@@ -572,10 +572,7 @@ private class GameView : Gtk.DrawingArea
                         }
                     });
         }
-        queue_draw_area ((int) (board_x + x * paving_size),
-                         (int) (board_y + y * paving_size),
-                         tile_size,
-                         tile_size);
+        queue_draw_tile (x, y);
     }
 
     private static int get_pixmap (Player color)
@@ -814,19 +811,23 @@ private class GameView : Gtk.DrawingArea
         else
             show_highlight = true;
 
-        queue_draw_area ((int) (board_x + old_highlight_x * paving_size),
-                         (int) (board_y + old_highlight_y * paving_size),
-                         tile_size,
-                         tile_size);
+        queue_draw_tile (old_highlight_x, old_highlight_y);
         if ((old_highlight_x != highlight_x)
          || (old_highlight_y != highlight_y))
-            queue_draw_area ((int) (board_x + highlight_x * paving_size),
-                             (int) (board_y + highlight_y * paving_size),
-                             tile_size,
-                             tile_size);
+            queue_draw_tile (highlight_x, highlight_y);
         return true;
     }
 
+    private void queue_draw_tile (uint8 x, uint8 y)
+        requires (x < game_size)
+        requires (y < game_size)
+    {
+        queue_draw_area (board_x + paving_size * (int) x,
+                         board_y + paving_size * (int) y,
+                         tile_size,
+                         tile_size);
+    }
+
     /*\
     * * Scoreboard
     \*/