--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/zoom.hpp	Wed Jun 13 11:45:14 2007 +0000
@@ -0,0 +1,50 @@
+/* $Id$ */
+
+/** @file zoom.hpp */
+
+#ifndef ZOOM_HPP
+#define ZOOM_HPP
+
+enum ZoomLevel {
+	/* Our possible zoom-levels */
+	ZOOM_LVL_NORMAL = 0,
+	ZOOM_LVL_OUT_2X,
+	ZOOM_LVL_OUT_4X,
+	ZOOM_LVL_OUT_8X,
+	ZOOM_LVL_OUT_16X,
+	ZOOM_LVL_END,
+
+	/* Here we define in which zoom viewports are */
+	ZOOM_LVL_VIEWPORT = ZOOM_LVL_NORMAL,
+	ZOOM_LVL_NEWS     = ZOOM_LVL_NORMAL,
+	ZOOM_LVL_INDUSTRY = ZOOM_LVL_OUT_2X,
+	ZOOM_LVL_TOWN     = ZOOM_LVL_OUT_2X,
+	ZOOM_LVL_AIRCRAFT = ZOOM_LVL_NORMAL,
+	ZOOM_LVL_SHIP     = ZOOM_LVL_NORMAL,
+	ZOOM_LVL_TRAIN    = ZOOM_LVL_NORMAL,
+	ZOOM_LVL_ROADVEH  = ZOOM_LVL_NORMAL,
+	ZOOM_LVL_WORLD_SCREENSHOT = ZOOM_LVL_NORMAL,
+
+	ZOOM_LVL_DETAIL   = ZOOM_LVL_OUT_2X, //! All zoomlevels below or equal to this, will result in details on the screen, like road-work, ...
+
+	ZOOM_LVL_MIN      = ZOOM_LVL_NORMAL,
+	ZOOM_LVL_MAX      = ZOOM_LVL_OUT_16X,
+};
+
+extern ZoomLevel _saved_scrollpos_zoom;
+
+static inline int ScaleByZoom(int value, ZoomLevel zoom)
+{
+	if (zoom == ZOOM_LVL_NORMAL) return value;
+	int izoom = (int)zoom - (int)ZOOM_LVL_NORMAL;
+	return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : value >> izoom;
+}
+
+static inline int UnScaleByZoom(int value, ZoomLevel zoom)
+{
+	if (zoom == ZOOM_LVL_NORMAL) return value;
+	int izoom = (int)zoom - (int)ZOOM_LVL_NORMAL;
+	return (zoom > ZOOM_LVL_NORMAL) ? value >> izoom : value << izoom;
+}
+
+#endif /* ZOOM_HPP */