/* $Id$ */ /* * This file is part of OpenTTD. * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2. * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>. */ /** @file zoom_func.h Functions related to zooming. */ #ifndef ZOOM_FUNC_H #define ZOOM_FUNC_H #include "zoom_type.h" /** * Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL) * When shifting right, value is rounded up * @param value value to shift * @param zoom zoom level to shift to * @return shifted value */ static inline int ScaleByZoom(int value, ZoomLevel zoom) { if (zoom == ZOOM_LVL_NORMAL) return value; int izoom = zoom - ZOOM_LVL_NORMAL; return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : (value + (1 << -izoom) - 1) >> -izoom; } /** * Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL) * When shifting right, value is rounded up * @param value value to shift * @param zoom zoom level to shift to * @return shifted value */ static inline int UnScaleByZoom(int value, ZoomLevel zoom) { if (zoom == ZOOM_LVL_NORMAL) return value; int izoom = zoom - ZOOM_LVL_NORMAL; return (zoom > ZOOM_LVL_NORMAL) ? (value + (1 << izoom) - 1) >> izoom : value << -izoom; } /** * Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL) * @param value value to shift * @param zoom zoom level to shift to * @return shifted value */ static inline int ScaleByZoomLower(int value, ZoomLevel zoom) { if (zoom == ZOOM_LVL_NORMAL) return value; int izoom = zoom - ZOOM_LVL_NORMAL; return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : value >> -izoom; } /** * Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL) * @param value value to shift * @param zoom zoom level to shift to * @return shifted value */ static inline int UnScaleByZoomLower(int value, ZoomLevel zoom) { if (zoom == ZOOM_LVL_NORMAL) return value; int izoom = zoom - ZOOM_LVL_NORMAL; return (zoom > ZOOM_LVL_NORMAL) ? value >> izoom : value << -izoom; } #endif /* ZOOM_FUNC_H */