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Diffstat (limited to 'src/zoom_func.h')
-rw-r--r-- | src/zoom_func.h | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/src/zoom_func.h b/src/zoom_func.h new file mode 100644 index 000000000..4a4fe83ff --- /dev/null +++ b/src/zoom_func.h @@ -0,0 +1,66 @@ +/* $Id$ */ + +/** @file zoom.hpp */ + +#ifndef ZOOM_FUNC_H +#define ZOOM_FUNC_H + +#include "zoom_type.h" + +extern ZoomLevel _saved_scrollpos_zoom; + +/** + * 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 */ |