Add marker-multi-policy parameter

This is to support user-configurable rendering behavior for
multi-geometries when using either point or interior placement
See #1573 and #1555

CHANGELOG.md

@@ -9,6 +9,8 @@ For a complete change history, see the git log.
 
 ## Unreleased
 
+- Added support for controlling rendering behavior of markers on multi-geometries `marker-multi-policy` (#1555,#1573)
+
 - Add DebugSymbolizer (#1366)
 
 

bindings/python/mapnik_markers_symbolizer.cpp

@@ -89,6 +89,12 @@ void export_markers_symbolizer()
         .value("LINE_PLACEMENT",mapnik::MARKER_LINE_PLACEMENT)
         ;
 
+    mapnik::enumeration_<mapnik::marker_multi_policy_e>("marker_multi_policy")
+        .value("EACH",mapnik::MARKER_EACH_MULTI)
+        .value("WHOLE",mapnik::MARKER_WHOLE_MULTI)
+        .value("LARGEST",mapnik::MARKER_LARGEST_MULTI)
+        ;
+
     class_<markers_symbolizer>("MarkersSymbolizer",
                                init<>("Default Markers Symbolizer - circle"))
         .def (init<mapnik::path_expression_ptr>("<path expression ptr>"))
@@ -143,6 +149,10 @@ void export_markers_symbolizer()
                       &markers_symbolizer::get_marker_placement,
                       &markers_symbolizer::set_marker_placement,
                       "Set/get the marker placement")
+        .add_property("multi_policy",
+                      &markers_symbolizer::get_marker_multi_policy,
+                      &markers_symbolizer::set_marker_multi_policy,
+                      "Set/get the marker multi geometry rendering policy")
         .add_property("comp_op",
                       &markers_symbolizer::comp_op,
                       &markers_symbolizer::set_comp_op,

include/mapnik/geom_util.hpp

@@ -329,6 +329,70 @@ bool centroid(PathType & path, double & x, double & y)
     return true;
 }
 
+// Compute centroid over a set of paths
+template <typename Iter>
+bool centroid_geoms(Iter start, Iter end, double & x, double & y)
+{
+  double x0 = 0.0;
+  double y0 = 0.0;
+  double x1 = 0.0;
+  double y1 = 0.0;
+  double start_x = x0;
+  double start_y = y0;
+
+  bool empty = true;
+
+  double atmp = 0.0;
+  double xtmp = 0.0;
+  double ytmp = 0.0;
+  unsigned count = 1;
+
+  while (start!=end)
+  {
+    typename Iter::value_type & path = *start++;
+    path.rewind(0);
+    unsigned command = path.vertex(&x0, &y0);
+    if (command == SEG_END) continue;
+    empty = false;
+
+    while (SEG_END != (command = path.vertex(&x1, &y1)))
+    {
+        double dx0 = x0 - start_x;
+        double dy0 = y0 - start_y;
+        double dx1 = x1 - start_x;
+        double dy1 = y1 - start_y;
+        double ai = dx0 * dy1 - dx1 * dy0;
+        atmp += ai;
+        xtmp += (dx1 + dx0) * ai;
+        ytmp += (dy1 + dy0) * ai;
+        x0 = x1;
+        y0 = y1;
+        ++count;
+    }
+  }
+
+  if ( empty ) return false;
+
+  if (count <= 2) {
+      x = (start_x + x0) * 0.5;
+      y = (start_y + y0) * 0.5;
+      return true;
+  }
+
+  if (atmp != 0)
+  {
+      x = (xtmp/(3*atmp)) + start_x;
+      y = (ytmp/(3*atmp)) + start_y;
+  }
+  else
+  {
+      x = x0;
+      y = y0;
+  }
+
+  return true;
+}
+
 template <typename PathType>
 bool hit_test(PathType & path, double x, double y, double tol)
 {

include/mapnik/marker_helpers.hpp

@@ -398,6 +398,68 @@ void setup_transform_scaling(agg::trans_affine & tr, box2d<double> const& bbox,
     }
 }
 
+// Apply markers to a feature with multiple geometries
+template <typename Converter>
+void apply_markers_multi(feature_impl & feature, Converter& converter, markers_symbolizer const& sym)
+{
+  std::size_t geom_count = feature.paths().size();
+  if (geom_count == 1)
+  {
+      converter.apply(feature.paths()[0]);
+  }
+  else if (geom_count > 1)
+  {
+      marker_multi_policy_e multi_policy = sym.get_marker_multi_policy();
+      marker_placement_e placement = sym.get_marker_placement();
+      if (placement == MARKER_POINT_PLACEMENT &&
+           multi_policy == MARKER_WHOLE_MULTI)
+      {
+          double x, y;
+          if (label::centroid_geoms(feature.paths().begin(), feature.paths().end(), x, y))
+          {
+              geometry_type pt(Point);
+              pt.move_to(x, y);
+              // unset any clipping since we're now dealing with a point
+              converter.template unset<clip_poly_tag>();
+              converter.apply(pt);
+          }
+      }
+      else if ((placement == MARKER_POINT_PLACEMENT || placement == MARKER_INTERIOR_PLACEMENT) &&
+                multi_policy == MARKER_LARGEST_MULTI)
+      {
+          // Only apply to path with largest envelope area
+          // TODO: consider using true area for polygon types
+          double maxarea = 0;
+          geometry_type* largest = 0;
+          BOOST_FOREACH(geometry_type & geom, feature.paths())
+          {
+              const box2d<double>& env = geom.envelope();
+              double area = env.width() * env.height();
+              if (area > maxarea)
+              {
+                  maxarea = area;
+                  largest = &geom;
+              }
+          }
+          if (largest)
+          {
+              converter.apply(*largest);
+          }
+      }
+      else
+      {
+          if (multi_policy != MARKER_EACH_MULTI && placement != MARKER_POINT_PLACEMENT)
+          {
+              MAPNIK_LOG_WARN(marker_symbolizer) << "marker_multi_policy != 'each' has no effect with marker_placement != 'point'";
+          }
+          BOOST_FOREACH(geometry_type & path, feature.paths())
+          {
+            converter.apply(path);
+          }
+      }
+  }
+}
+
 }
 
 #endif //MAPNIK_MARKER_HELPERS_HPP

include/mapnik/markers_symbolizer.hpp

@@ -46,6 +46,15 @@ enum marker_placement_enum {
 
 DEFINE_ENUM( marker_placement_e, marker_placement_enum );
 
+enum marker_multi_policy_enum {
+    MARKER_EACH_MULTI, // each component in a multi gets its marker
+    MARKER_WHOLE_MULTI, // consider all components of a multi as a whole
+    MARKER_LARGEST_MULTI, // only the largest component of a multi gets a marker
+    marker_multi_policy_enum_MAX
+};
+
+DEFINE_ENUM( marker_multi_policy_e, marker_multi_policy_enum );
+
 struct MAPNIK_DECL markers_symbolizer :
         public symbolizer_with_image, public symbolizer_base
 {
@@ -74,6 +83,8 @@ public:
     boost::optional<stroke> get_stroke() const;
     void set_marker_placement(marker_placement_e marker_p);
     marker_placement_e get_marker_placement() const;
+    void set_marker_multi_policy(marker_multi_policy_e marker_p);
+    marker_multi_policy_e get_marker_multi_policy() const;
 private:
     expression_ptr width_;
     expression_ptr height_;
@@ -86,6 +97,7 @@ private:
     boost::optional<float> opacity_;
     boost::optional<stroke> stroke_;
     marker_placement_e marker_p_;
+    marker_multi_policy_e marker_mp_;
 };
 
 }

include/mapnik/vertex_converters.hpp

@@ -347,6 +347,16 @@ struct vertex_converter : private boost::noncopyable
             disp_.vec_[index]=1;
     }
 
+    template <typename Conv>
+    void unset()
+    {
+        typedef typename boost::mpl::find<conv_types,Conv>::type iter;
+        typedef typename boost::mpl::end<conv_types>::type end;
+        std::size_t index = boost::mpl::distance<iter,end>::value - 1;
+        if (index < disp_.vec_.size())
+            disp_.vec_[index]=0;
+    }
+
 
     detail::dispatcher<args_type,conv_types> disp_;
 };

src/agg/process_markers_symbolizer.cpp

@@ -26,6 +26,7 @@
 #include <mapnik/agg_rasterizer.hpp>
 
 #include <mapnik/debug.hpp>
+#include <mapnik/feature.hpp>
 #include <mapnik/geom_util.hpp>
 #include <mapnik/expression_evaluator.hpp>
 #include <mapnik/vertex_converters.hpp>
@@ -136,10 +137,7 @@ void agg_renderer<T>::process(markers_symbolizer const& sym,
                     }
                     converter.template set<transform_tag>(); //always transform
                     if (sym.smooth() > 0.0) converter.template set<smooth_tag>(); // optional smooth converter
-                    BOOST_FOREACH(geometry_type & geom, feature.paths())
+                    apply_markers_multi(feature, converter, sym);
-                    {
-                        converter.apply(geom);
-                    }
                 }
                 else
                 {
@@ -172,10 +170,7 @@ void agg_renderer<T>::process(markers_symbolizer const& sym,
                     }
                     converter.template set<transform_tag>(); //always transform
                     if (sym.smooth() > 0.0) converter.template set<smooth_tag>(); // optional smooth converter
-                    BOOST_FOREACH(geometry_type & geom, feature.paths())
+                    apply_markers_multi(feature, converter, sym);
-                    {
-                        converter.apply(geom);
-                    }
                 }
             }
             else // raster markers
@@ -207,11 +202,7 @@ void agg_renderer<T>::process(markers_symbolizer const& sym,
                 }
                 converter.template set<transform_tag>(); //always transform
                 if (sym.smooth() > 0.0) converter.template set<smooth_tag>(); // optional smooth converter
-
+                apply_markers_multi(feature, converter, sym);
-                BOOST_FOREACH(geometry_type & geom, feature.paths())
-                {
-                    converter.apply(geom);
-                }
             }
         }
     }

src/cairo_renderer.cpp

@@ -1706,10 +1706,7 @@ void cairo_renderer_base::process(markers_symbolizer const& sym,
                     }
                     converter.set<transform_tag>(); //always transform
                     if (sym.smooth() > 0.0) converter.set<smooth_tag>(); // optional smooth converter
-                    BOOST_FOREACH(geometry_type & geom, feature.paths())
+                    apply_markers_multi(feature, converter, sym);
-                    {
-                        converter.apply(geom);
-                    }
                 }
                 else
                 {
@@ -1734,10 +1731,7 @@ void cairo_renderer_base::process(markers_symbolizer const& sym,
                     }
                     converter.set<transform_tag>(); //always transform
                     if (sym.smooth() > 0.0) converter.set<smooth_tag>(); // optional smooth converter
-                    BOOST_FOREACH(geometry_type & geom, feature.paths())
+                    apply_markers_multi(feature, converter, sym);
-                    {
-                        converter.apply(geom);
-                    }
                 }
             }
             else // raster markers
@@ -1767,10 +1761,7 @@ void cairo_renderer_base::process(markers_symbolizer const& sym,
                     }
                     converter.set<transform_tag>(); //always transform
                     if (sym.smooth() > 0.0) converter.set<smooth_tag>(); // optional smooth converter
-                    BOOST_FOREACH(geometry_type & geom, feature.paths())
+                    apply_markers_multi(feature, converter, sym);
-                    {
-                        converter.apply(geom);
-                    }
                 }
             }
         }

src/grid/process_markers_symbolizer.cpp

@@ -163,10 +163,7 @@ void grid_renderer<T>::process(markers_symbolizer const& sym,
                     }
                     converter.template set<transform_tag>(); //always transform
                     if (sym.smooth() > 0.0) converter.template set<smooth_tag>(); // optional smooth converter
-                    BOOST_FOREACH(geometry_type & geom, feature.paths())
+                    apply_markers_multi(feature, converter, sym);
-                    {
-                        converter.apply(geom);
-                    }
                 }
                 else
                 {
@@ -208,10 +205,7 @@ void grid_renderer<T>::process(markers_symbolizer const& sym,
                     }
                     converter.template set<transform_tag>(); //always transform
                     if (sym.smooth() > 0.0) converter.template set<smooth_tag>(); // optional smooth converter
-                    BOOST_FOREACH(geometry_type & geom, feature.paths())
+                    apply_markers_multi(feature, converter, sym);
-                    {
-                        converter.apply(geom);
-                    }
                 }
             }
             else // raster markers
@@ -256,10 +250,7 @@ void grid_renderer<T>::process(markers_symbolizer const& sym,
                 }
                 converter.template set<transform_tag>(); //always transform
                 if (sym.smooth() > 0.0) converter.template set<smooth_tag>(); // optional smooth converter
-                BOOST_FOREACH(geometry_type & geom, feature.paths())
+                apply_markers_multi(feature, converter, sym);
-                {
-                    converter.apply(geom);
-                }
             }
         }
     }

src/load_map.cpp

@@ -1027,6 +1027,10 @@ void map_parser::parse_markers_symbolizer(rule & rule, xml_node const& node)
 
         marker_placement_e placement = node.get_attr<marker_placement_e>("placement",sym.get_marker_placement());
         sym.set_marker_placement(placement);
+
+        marker_multi_policy_e mpolicy = node.get_attr<marker_multi_policy_e>("multi-policy",sym.get_marker_multi_policy());
+        sym.set_marker_multi_policy(mpolicy);
+
         parse_symbolizer_base(sym, node);
         rule.append(sym);
     }

src/markers_symbolizer.cpp

@@ -37,6 +37,15 @@ static const char * marker_placement_strings[] = {
 
 IMPLEMENT_ENUM( marker_placement_e, marker_placement_strings )
 
+static const char * marker_multi_policy_strings[] = {
+    "each",
+    "whole",
+    "largest",
+    ""
+};
+
+IMPLEMENT_ENUM( marker_multi_policy_e, marker_multi_policy_strings )
+
 markers_symbolizer::markers_symbolizer()
     : symbolizer_with_image(parse_path("shape://ellipse")),
       symbolizer_base(),
@@ -46,7 +55,10 @@ markers_symbolizer::markers_symbolizer()
       allow_overlap_(false),
       spacing_(100.0),
       max_error_(0.2),
-      marker_p_(MARKER_POINT_PLACEMENT) { }
+      marker_p_(MARKER_POINT_PLACEMENT),
+      // TODO: consider defaulting to MARKER_WHOLE_MULTI,
+      //       for backward compatibility with 2.0.0
+      marker_mp_(MARKER_EACH_MULTI) { }
 
 markers_symbolizer::markers_symbolizer(path_expression_ptr const& filename)
     : symbolizer_with_image(filename),
@@ -57,7 +69,10 @@ markers_symbolizer::markers_symbolizer(path_expression_ptr const& filename)
       allow_overlap_(false),
       spacing_(100.0),
       max_error_(0.2),
-      marker_p_(MARKER_POINT_PLACEMENT) { }
+      marker_p_(MARKER_POINT_PLACEMENT),
+      // TODO: consider defaulting to MARKER_WHOLE_MULTI,
+      //       for backward compatibility with 2.0.0
+      marker_mp_(MARKER_EACH_MULTI) { }
 
 markers_symbolizer::markers_symbolizer(markers_symbolizer const& rhs)
     : symbolizer_with_image(rhs),
@@ -71,7 +86,8 @@ markers_symbolizer::markers_symbolizer(markers_symbolizer const& rhs)
       fill_(rhs.fill_),
       fill_opacity_(rhs.fill_opacity_),
       stroke_(rhs.stroke_),
-      marker_p_(rhs.marker_p_) {}
+      marker_p_(rhs.marker_p_),
+      marker_mp_(rhs.marker_mp_) {}
 
 void markers_symbolizer::set_ignore_placement(bool ignore_placement)
 {
@@ -173,4 +189,14 @@ marker_placement_e markers_symbolizer::get_marker_placement() const
     return marker_p_;
 }
 
+void markers_symbolizer::set_marker_multi_policy(marker_multi_policy_e marker_mp)
+{
+    marker_mp_ = marker_mp;
+}
+
+marker_multi_policy_e markers_symbolizer::get_marker_multi_policy() const
+{
+    return marker_mp_;
+}
+
 }

src/save_map.cpp

@@ -311,6 +311,10 @@ public:
         {
             set_attr( sym_node, "placement", sym.get_marker_placement() );
         }
+        if ( sym.get_marker_multi_policy() != dfl.get_marker_multi_policy() || explicit_defaults_ )
+        {
+            set_attr( sym_node, "multi-policy", sym.get_marker_multi_policy() );
+        }
         if (sym.get_image_transform())
         {
             std::string tr_str = sym.get_image_transform_string();

src/xml_tree.cpp

@@ -486,6 +486,7 @@ compile_get_attr(std::string);
 compile_get_attr(filter_mode_e);
 compile_get_attr(point_placement_e);
 compile_get_attr(marker_placement_e);
+compile_get_attr(marker_multi_policy_e);
 compile_get_attr(pattern_alignment_e);
 compile_get_attr(line_rasterizer_e);
 compile_get_attr(colorizer_mode);

tests/cpp_tests/label_algo_test.cpp

@@ -31,6 +31,9 @@ int main( int, char*[] )
     BOOST_TEST( x == 25 );
     BOOST_TEST( y == 25 );
     
+    // TODO - centroid and interior should be equal but they appear not to be (check largest)
+    // MULTIPOLYGON(((-52 40,-60 32,-68 40,-60 48,-52 40)),((-60 50,-80 30,-100 49.9999999999999,-80.0000000000001 70,-60 50)),((-52 60,-60 52,-68 60,-60 68,-52 60)))
+
     if (!::boost::detail::test_errors()) {
         std::clog << "C++ label algorithms: \x1b[1;32m✓ \x1b[0m\n";
 #if BOOST_VERSION >= 104600

tests/python_tests/object_test.py

@@ -209,6 +209,7 @@ def test_markers_symbolizer():
     eq_(p.fill_opacity,None)
     eq_(p.filename,'shape://ellipse')
     eq_(p.placement,mapnik.marker_placement.POINT_PLACEMENT)
+    eq_(p.multi_policy,mapnik.marker_multi_policy.EACH)
     eq_(p.fill,None)
     eq_(p.ignore_placement,False)
     eq_(p.spacing,100)
@@ -239,10 +240,14 @@ def test_markers_symbolizer():
     p.allow_overlap = True
     p.opacity = 0.5
     p.fill_opacity = 0.5
+    p.placement = mapnik.marker_placement.LINE_PLACEMENT
+    p.multi_policy = mapnik.marker_multi_policy.WHOLE
 
     eq_(p.allow_overlap, True)
     eq_(p.opacity, 0.5)
     eq_(p.fill_opacity, 0.5)
+    eq_(p.multi_policy,mapnik.marker_multi_policy.WHOLE)
+    eq_(p.placement,mapnik.marker_placement.LINE_PLACEMENT)
 
     #https://github.com/mapnik/mapnik/issues/1285
     #https://github.com/mapnik/mapnik/issues/1427

tests/visual_tests/data/marker-multi-policy.csv

@@ -0,0 +1,3 @@
+i|wkt
+1|MULTIPOLYGON(((-10 -50,-21.7157287525381 -78.2842712474619,-49.9999999999999 -90,-78.2842712474618 -78.284271247462,-90 -50.0000000000001,-78.284271247462 -21.7157287525382,-50.0000000000002 -10,-21.7157287525383 -21.7157287525379,-10 -50)),((90 -50,78.2842712474619 -78.2842712474619,50.0000000000001 -90,21.7157287525382 -78.284271247462,10 -50.0000000000001,21.715728752538 -21.7157287525382,49.9999999999998 -10,78.2842712474617 -21.7157287525379,90 -50)),((90 50,50.0000000000001 10,10 49.9999999999999,49.9999999999998 90,90 50)))
+2|MULTIPOLYGON(((-52 40,-60 32,-68 40,-60 48,-52 40)),((-60 50,-80 30,-100 49.9999999999999,-80.0000000000001 70,-60 50)),((-52 60,-60 52,-68 60,-60 68,-52 60)))

tests/visual_tests/styles/marker-multi-policy.xml

@@ -0,0 +1,36 @@
+<Map maximum-extent="-100,-100,100,100">
+<Style name="each">
+  <Rule>
+    <Filter>[i] = 1</Filter>
+    <MarkersSymbolizer placement="point" fill="red" width="30" allow-overlap="true"/>
+  </Rule>
+</Style>
+<Style name="whole">
+  <Rule>
+    <Filter>[i] = 1</Filter>
+    <MarkersSymbolizer placement="point" multi-policy="whole" fill="yellow" width="20" allow-overlap="true"/>
+  </Rule>
+</Style>
+<Style name="largest">
+  <Rule>
+    <Filter>[i] = 2</Filter>
+    <MarkersSymbolizer placement="point" multi-policy="largest" fill="blue" width="10" allow-overlap="true"/>
+  </Rule>
+</Style>
+<Style name="boundary">
+  <Rule>
+    <LineSymbolizer />
+  </Rule>
+</Style>
+<Layer name="multi">
+    <StyleName>boundary</StyleName>
+    <StyleName>each</StyleName>
+    <StyleName>whole</StyleName>
+    <StyleName>largest</StyleName>
+    <Datasource>
+       <Parameter name="type">csv</Parameter>
+       <Parameter name="file">../data/marker-multi-policy.csv</Parameter>
+       <Parameter name="separator">|</Parameter>
+    </Datasource>
+  </Layer>
+</Map>

tests/visual_tests/test.py

@@ -27,6 +27,7 @@ files = [
     {'name': "lines-2", 'sizes': sizes_few_square},
     {'name': "lines-3", 'sizes': sizes_few_square},
     {'name': "lines-shield", 'sizes': sizes_few_square},
+    {'name': "marker-multi-policy", 'sizes':[(600,400)]},
     {'name': "simple-E"},
     {'name': "simple-NE"},
     {'name': "simple-NW"},