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new file 100644
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/* $Id$ */
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/** @file zoom.hpp */
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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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