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https://github.com/JGRennison/OpenTTD-patches.git
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74 lines
2.4 KiB
C
74 lines
2.4 KiB
C
/* $Id$ */
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/*
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* This file is part of OpenTTD.
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* 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.
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* 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.
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* 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/>.
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*/
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/** @file zoom_func.h Functions related to zooming. */
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#ifndef ZOOM_FUNC_H
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#define ZOOM_FUNC_H
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#include "zoom_type.h"
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extern ZoomLevel _saved_scrollpos_zoom;
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/**
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* Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL)
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* When shifting right, value is rounded up
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* @param value value to shift
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* @param zoom zoom level to shift to
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* @return shifted value
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*/
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static inline int ScaleByZoom(int value, ZoomLevel zoom)
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{
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if (zoom == ZOOM_LVL_NORMAL) return value;
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int izoom = zoom - ZOOM_LVL_NORMAL;
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return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : (value + (1 << -izoom) - 1) >> -izoom;
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}
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/**
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* Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL)
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* When shifting right, value is rounded up
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* @param value value to shift
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* @param zoom zoom level to shift to
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* @return shifted value
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*/
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static inline int UnScaleByZoom(int value, ZoomLevel zoom)
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{
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if (zoom == ZOOM_LVL_NORMAL) return value;
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int izoom = zoom - ZOOM_LVL_NORMAL;
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return (zoom > ZOOM_LVL_NORMAL) ? (value + (1 << izoom) - 1) >> izoom : value << -izoom;
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}
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/**
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* Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL)
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* @param value value to shift
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* @param zoom zoom level to shift to
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* @return shifted value
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*/
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static inline int ScaleByZoomLower(int value, ZoomLevel zoom)
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{
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if (zoom == ZOOM_LVL_NORMAL) return value;
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int izoom = zoom - ZOOM_LVL_NORMAL;
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return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : value >> -izoom;
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}
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/**
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* Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL)
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* @param value value to shift
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* @param zoom zoom level to shift to
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* @return shifted value
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*/
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static inline int UnScaleByZoomLower(int value, ZoomLevel zoom)
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{
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if (zoom == ZOOM_LVL_NORMAL) return value;
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int izoom = zoom - ZOOM_LVL_NORMAL;
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return (zoom > ZOOM_LVL_NORMAL) ? value >> izoom : value << -izoom;
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}
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#endif /* ZOOM_FUNC_H */
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