/* Zooms a viewport in a window in or out

 * No button handling or what so ever */

bool DoZoomInOutWindow(ZoomStateChange how, Window *w)

{

	ViewPort *vp;

	assert(w != NULL);

	vp = w->viewport;

	switch (how) {

		case ZOOM_NONE:

			/* On initialisation of the viewport we don't do anything. */

			break;

		case ZOOM_IN:

			if (vp->zoom == ZOOM_LVL_MIN) return false;

			vp->zoom = (ZoomLevel)((int)vp->zoom - 1);

			vp->virtual_width >>= 1;

			vp->virtual_height >>= 1;

			w->viewport->scrollpos_x += vp->virtual_width >> 1;

			w->viewport->scrollpos_y += vp->virtual_height >> 1;

			w->viewport->dest_scrollpos_x = w->viewport->scrollpos_x;

			w->viewport->dest_scrollpos_y = w->viewport->scrollpos_y;

			break;

		case ZOOM_OUT:

			if (vp->zoom == ZOOM_LVL_MAX) return false;

			vp->zoom = (ZoomLevel)((int)vp->zoom + 1);

			w->viewport->scrollpos_x -= vp->virtual_width >> 1;

			w->viewport->scrollpos_y -= vp->virtual_height >> 1;

			w->viewport->dest_scrollpos_x = w->viewport->scrollpos_x;

			w->viewport->dest_scrollpos_y = w->viewport->scrollpos_y;

			vp->virtual_width <<= 1;

			vp->virtual_height <<= 1;

			break;

	}

	if (vp != NULL) { // the vp can be null when how == ZOOM_NONE

		vp->virtual_left = w->viewport->scrollpos_x;

		vp->virtual_top = w->viewport->scrollpos_y;

	}

	/* Update the windows that have zoom-buttons to perhaps disable their buttons */

	w->InvalidateData();

	return true;

}

void ZoomInOrOutToCursorWindow(bool in, Window *w)

{

	assert(w != NULL);

	if (_game_mode != GM_MENU) {

		ViewPort *vp = w->viewport;

		if ((in && vp->zoom == ZOOM_LVL_MIN) || (!in && vp->zoom == ZOOM_LVL_MAX)) return;

		Point pt = GetTileZoomCenterWindow(in, w);

		if (pt.x != -1) {

			ScrollWindowTo(pt.x, pt.y, -1, w, true);

			DoZoomInOutWindow(in ? ZOOM_IN : ZOOM_OUT, w);