Codechange: Make use of Rect Width/Height helpers.

src/bitmap_type.h

@@ -58,8 +58,8 @@ public:
 	void Initialize(const Rect &r)
 	{
 		this->tile = TileXY(r.left, r.top);
-		this->w = r.right - r.left + 1;
-		this->h = r.bottom - r.top + 1;
+		this->w = r.Width();
+		this->h = r.Height();
 		this->data.clear();
 		this->data.resize(Index(w, h));
 	}