Import combined Enhanced viewport: zoom out, overlays & tooltips (r53_27127) patch

https://www.tt-forums.net/viewtopic.php?f=33&t=53394

src/smallmap_gui.h

@@ -20,9 +20,34 @@
 #include "linkgraph/linkgraph_gui.h"
 #include "widgets/smallmap_widget.h"
 
+static const int NUM_NO_COMPANY_ENTRIES = 4; ///< Number of entries in the owner legend that are not companies.
+
+/** Mapping of tile type to importance of the tile (higher number means more interesting to show). */
+static const byte _tiletype_importance[] = {
+	2, // MP_CLEAR
+	8, // MP_RAILWAY
+	7, // MP_ROAD
+	5, // MP_HOUSE
+	2, // MP_TREES
+	9, // MP_STATION
+	2, // MP_WATER
+	1, // MP_VOID
+	6, // MP_INDUSTRY
+	8, // MP_TUNNELBRIDGE
+	2, // MP_OBJECT
+	0,
+};
+
 /* set up the cargos to be displayed in the smallmap's route legend */
 void BuildLinkStatsLegend();
 
+struct TunnelBridgeToMap {
+	TileIndex from_tile;
+	TileIndex to_tile;
+	uint8 colour;
+};
+typedef SmallVector<TunnelBridgeToMap, 64> TunnelBridgeToMapVector;
+
 void BuildIndustriesLegend();
 void ShowSmallMap();
 void BuildLandLegend();
@@ -147,7 +172,6 @@ protected:
 		return Company::IsValidID(_local_company) ? 1U << _local_company : 0xffffffff;
 	}
 
-	void RebuildColourIndexIfNecessary();
 	uint GetNumberRowsLegend(uint columns) const;
 	void SelectLegendItem(int click_pos, LegendAndColour *legend, int end_legend_item, int begin_legend_item = 0);
 	void SwitchMapType(SmallMapType map_type);
@@ -176,6 +200,8 @@ public:
 	SmallMapWindow(WindowDesc *desc, int window_number);
 	virtual ~SmallMapWindow() { delete this->overlay; }
 
+	static void RebuildColourIndexIfNecessary();
+
 	void SmallMapCenterOnCurrentPos();
 	Point GetStationMiddle(const Station *st) const;