public static void setDrawingArea(int h, int j, int w, int l) {
		if (j < 0)
			j = 0;
		if (l < 0)
			l = 0;
		if (w > width)
			w = width;
		if (h > height)
			h = height;
		topX = j;
		topY = l;
		bottomX = w;
		bottomY = h;
		centerX = bottomX - 1;
		viewportCentreX = bottomX / 2;
		viewportCentreY = bottomY / 2;
	}