Merge branch 'master' into boost_1_67

SConstruct

@@ -1275,7 +1275,10 @@ if not preconfigured:
     color_print(4,"Configuring on %s in *%s*..." % (env['PLATFORM'],mode))
 
     cxx_version = call("%s --version" % env["CXX"] ,silent=True)
+    if cxx_version:
         color_print(5, "CXX %s" % cxx_version.decode("utf8"))
+    else:
+        color_print(5, "Could not detect CXX compiler")
 
     env['MISSING_DEPS'] = []
     env['SKIPPED_DEPS'] = []

src/load_map.cpp

@@ -150,6 +150,76 @@ private:
 };
 
 
+struct allow_overlap_visitor
+{
+    bool operator()(point_symbolizer const&)            { return true; }
+    bool operator()(line_symbolizer const&)             { return false; }
+    bool operator()(line_pattern_symbolizer const&)     { return false; }
+    bool operator()(polygon_symbolizer const&)          { return false; }
+    bool operator()(polygon_pattern_symbolizer const&)  { return false; }
+    bool operator()(raster_symbolizer const&)           { return false; }
+    bool operator()(shield_symbolizer const&)           { return false; }
+    bool operator()(text_symbolizer const&)             { return true; }
+    bool operator()(building_symbolizer const&)         { return false; }
+    bool operator()(markers_symbolizer const&)          { return true; }
+    bool operator()(group_symbolizer const&)            { return false; }
+    bool operator()(debug_symbolizer const&)            { return true; } //Requires the quadtree
+    bool operator()(dot_symbolizer const&)              { return false; }
+};
+
+// If all symbolizers declare 'allow_overlap: true' (their placement is independent
+// from already placed symbols), there is no need to check collisions with subsequent
+// symbolizers. To avoid building the quadtree unnecessarily we set
+// the 'ignore_placement' flag
+void map_apply_overlap_optimization(Map &map)
+{
+    bool ignore_placement = true;
+    for (auto const & style : map.styles())
+    {
+        for (auto const & rule : style.second.get_rules())
+        {
+            for (auto const & sym : rule)
+            {
+                struct allow_overlap_visitor visitor;
+                if (util::apply_visitor(visitor, sym))
+                {
+                    symbolizer_base const & sb = sym.get_unchecked<markers_symbolizer>();
+                    auto prop_it = sb.properties.find(keys::allow_overlap);
+                    if (prop_it != sb.properties.end())
+                    {
+                        if (prop_it->second == true)
+                        {
+                            continue;
+                        }
+                    }
+                    ignore_placement = false;
+                    break;
+                }
+            }
+        }
+    }
+
+    if (ignore_placement)
+    {
+        for (auto & style : map.styles())
+        {
+            for (auto & rule : style.second.get_rules_nonconst())
+            {
+                for (auto & sym : rule)
+                {
+                    struct allow_overlap_visitor visitor;
+                    if (util::apply_visitor(visitor, sym))
+                    {
+                        symbolizer_base & sb = sym.get_unchecked<markers_symbolizer>();
+                        sb.properties[keys::ignore_placement] = true;
+                    }
+                }
+            }
+        }
+        MAPNIK_LOG_DEBUG(load_map) << "setting ignore_placement=true due to all rules having allow_overlap=true";
+    }
+}
+
 void load_map(Map & map, std::string const& filename, bool strict, std::string base_path)
 {
     xml_tree tree;
@@ -157,6 +227,7 @@ void load_map(Map & map, std::string const& filename, bool strict, std::string b
     read_xml(filename, tree.root());
     map_parser parser(map, strict, filename);
     parser.parse_map(map, tree.root(), base_path);
+    map_apply_overlap_optimization(map);
 }
 
 void load_map_string(Map & map, std::string const& str, bool strict, std::string base_path)
@@ -172,6 +243,7 @@ void load_map_string(Map & map, std::string const& str, bool strict, std::string
     }
     map_parser parser(map, strict, base_path);
     parser.parse_map(map, tree.root(), base_path);
+    map_apply_overlap_optimization(map);
 }
 
 void map_parser::parse_map(Map & map, xml_node const& node, std::string const& base_path)