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/* $Id$ */

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/** @file zoom.hpp */

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#ifndef ZOOM_HPP

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#define ZOOM_HPP

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enum ZoomLevel {

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	/* Our possible zoom-levels */

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	ZOOM_LVL_BEGIN  = 0,

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	ZOOM_LVL_NORMAL = 0,

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	ZOOM_LVL_OUT_2X,

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	ZOOM_LVL_OUT_4X,

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	ZOOM_LVL_OUT_8X,

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	ZOOM_LVL_END,

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	/* Here we define in which zoom viewports are */

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	ZOOM_LVL_VIEWPORT = ZOOM_LVL_NORMAL,

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	ZOOM_LVL_NEWS     = ZOOM_LVL_NORMAL,

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	ZOOM_LVL_INDUSTRY = ZOOM_LVL_OUT_2X,

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	ZOOM_LVL_TOWN     = ZOOM_LVL_OUT_2X,

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	ZOOM_LVL_AIRCRAFT = ZOOM_LVL_NORMAL,

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	ZOOM_LVL_SHIP     = ZOOM_LVL_NORMAL,

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	ZOOM_LVL_TRAIN    = ZOOM_LVL_NORMAL,

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	ZOOM_LVL_ROADVEH  = ZOOM_LVL_NORMAL,

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	ZOOM_LVL_WORLD_SCREENSHOT = ZOOM_LVL_NORMAL,

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	ZOOM_LVL_DETAIL   = ZOOM_LVL_OUT_2X, ///< All zoomlevels below or equal to this, will result in details on the screen, like road-work, ...

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	ZOOM_LVL_MIN      = ZOOM_LVL_NORMAL,

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	ZOOM_LVL_MAX      = ZOOM_LVL_OUT_8X,

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};

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extern ZoomLevel _saved_scrollpos_zoom;

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DECLARE_POSTFIX_INCREMENT(ZoomLevel)

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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_HPP */