Add viaroute suport for new API

src/engine/guidance/assemble_overview.cpp

@@ -0,0 +1,99 @@
+#ifndef ENGINE_GUIDANCE_ASSEMBLE_OVERVIEW_HPP
+#define ENGINE_GUIDANCE_ASSEMBLE_OVERVIEW_HPP
+
+#include "engine/guidance/leg_geometry.hpp"
+#include "engine/douglas_peucker.hpp"
+#include "util/tiles.hpp"
+
+#include <vector>
+#include <tuple>
+
+namespace osrm
+{
+namespace engine
+{
+namespace guidance
+{
+namespace
+{
+
+unsigned calculateOverviewZoomLevel(const std::vector<LegGeometry> &leg_geometries)
+{
+    int min_lon = std::numeric_limits<int>::max();
+    int min_lat = std::numeric_limits<int>::max();
+    int max_lon = -std::numeric_limits<int>::max();
+    int max_lat = -std::numeric_limits<int>::max();
+
+    for (const auto &leg_geometry : leg_geometries)
+    {
+        for (const auto coord : leg_geometry.locations)
+        {
+            min_lon = std::min(min_lon, coord.lon);
+            max_lon = std::max(max_lon, coord.lon);
+            min_lat = std::min(min_lat, coord.lat);
+            max_lat = std::max(max_lat, coord.lat);
+        }
+    }
+
+    return util::tiles::getBBMaxZoomTile(min_lon, min_lat, max_lon, max_lat).z;
+}
+
+std::vector<util::FixedPointCoordinate> simplifyGeometry(const std::vector<LegGeometry> &leg_geometries, const unsigned zoom_level)
+{
+    std::vector<util::FixedPointCoordinate> overview_geometry;
+    auto leg_index = 0UL;
+    for (const auto geometry : leg_geometries)
+    {
+        auto simplified_geometry =
+            douglasPeucker(geometry.locations.begin(), geometry.locations.end(), zoom_level);
+        // not the last leg
+        if (leg_index < leg_geometries.size() - 1)
+        {
+            simplified_geometry.pop_back();
+        }
+        overview_geometry.insert(overview_geometry.end(), simplified_geometry.begin(),
+                                 simplified_geometry.end());
+    }
+    return overview_geometry;
+}
+}
+
+std::vector<util::FixedPointCoordinate>
+assembleOverview(const std::vector<LegGeometry> &leg_geometries, const bool use_simplification)
+{
+    if (use_simplification)
+    {
+        const auto zoom_level = calculateOverviewZoomLevel(leg_geometries);
+        return simplifyGeometry(leg_geometries, zoom_level);
+    }
+    BOOST_ASSERT(!use_simplification);
+
+    auto overview_size = std::accumulate(leg_geometries.begin(), leg_geometries.end(), 0,
+                                         [](const std::size_t sum, const LegGeometry &leg_geometry)
+                                         {
+                                             return sum + leg_geometry.locations.size();
+                                         }) -
+                         leg_geometries.size() + 1;
+    std::vector<util::FixedPointCoordinate> overview_geometry;
+    overview_geometry.reserve(overview_size);
+
+    auto leg_index = 0UL;
+    for (const auto geometry : leg_geometries)
+    {
+        auto begin = geometry.locations.begin();
+        auto end = geometry.locations.end();
+        if (leg_index < leg_geometries.size() - 1)
+        {
+            end = std::prev(end);
+        }
+        overview_geometry.insert(overview_geometry.end(), begin, end);
+    }
+
+    return overview_geometry;
+}
+
+} // namespace guidance
+} // namespace engine
+} // namespace osrm
+
+#endif