add support for drawing all geometry verticies with debug symbolizer mode=vertex and expose in python - closes #1848

bindings/python/mapnik_python.cpp

@@ -62,6 +62,7 @@ void export_polygon_pattern_symbolizer();
 void export_raster_symbolizer();
 void export_text_placement();
 void export_shield_symbolizer();
+void export_debug_symbolizer();
 void export_font_engine();
 void export_projection();
 void export_proj_transform();
@@ -463,6 +464,7 @@ BOOST_PYTHON_MODULE(_mapnik)
     export_raster_symbolizer();
     export_text_placement();
     export_shield_symbolizer();
+    export_debug_symbolizer();
     export_font_engine();
     export_projection();
     export_proj_transform();

include/mapnik/debug_symbolizer.hpp

@@ -30,10 +30,25 @@
 namespace mapnik
 {
 
+enum debug_symbolizer_mode_enum {
+    DEBUG_SYM_MODE_COLLISION,
+    DEBUG_SYM_MODE_VERTEX,
+    debug_symbolizer_mode_enum_MAX
+};
+
+DEFINE_ENUM( debug_symbolizer_mode_e, debug_symbolizer_mode_enum );
+
 struct MAPNIK_DECL debug_symbolizer :
         public symbolizer_base
 {
-    debug_symbolizer() : symbolizer_base() {}
+    debug_symbolizer();
+    debug_symbolizer(debug_symbolizer const& rhs);
+    debug_symbolizer_mode_e get_mode() const;
+    void set_mode(debug_symbolizer_mode_e mode);
+
+private:
+    debug_symbolizer_mode_e mode_;
+
 };
 
 }

src/agg/process_debug_symbolizer.cpp

@@ -52,10 +52,37 @@ void agg_renderer<T>::process(debug_symbolizer const& sym,
                               mapnik::feature_impl & feature,
                               proj_transform const& prj_trans)
 {
-    label_collision_detector4::query_iterator itr = detector_->begin(), end = detector_->end();
-    for (;itr!=end; itr++)
+    debug_symbolizer_mode_e mode = sym.get_mode();
+    if (mode == DEBUG_SYM_MODE_COLLISION)
     {
-        draw_rect(pixmap_, itr->box);
+        label_collision_detector4::query_iterator itr = detector_->begin(), end = detector_->end();
+        for (;itr!=end; itr++)
+        {
+            draw_rect(pixmap_, itr->box);
+        }
+    }
+    else if (mode == DEBUG_SYM_MODE_VERTEX)
+    {
+        for (unsigned i=0; i<feature.num_geometries(); ++i)
+        {
+            geometry_type const& geom = feature.get_geometry(i);
+            double x;
+            double y;
+            double z = 0;
+            geom.rewind(0);
+            unsigned cmd = 1;
+            while ((cmd = geom.vertex(&x, &y)) != mapnik::SEG_END)
+            {
+                if (cmd == SEG_CLOSE) continue;
+                prj_trans.backward(x,y,z);
+                t_.forward(&x,&y);
+                pixmap_.setPixel(x,y,0xff0000ff);
+                pixmap_.setPixel(x-1,y-1,0xff0000ff);
+                pixmap_.setPixel(x+1,y+1,0xff0000ff);
+                pixmap_.setPixel(x-1,y+1,0xff0000ff);
+                pixmap_.setPixel(x+1,y-1,0xff0000ff);
+            }
+        }
     }
 }
 

src/build.py

@@ -109,6 +109,7 @@ else: # unix, non-macos
 
 source = Split(
     """
+    debug_symbolizer.cpp
     request.cpp
     well_known_srs.cpp
     params.cpp

src/load_map.cpp

@@ -1531,8 +1531,10 @@ void map_parser::parse_raster_symbolizer(rule & rule, xml_node const & sym)
 void map_parser::parse_debug_symbolizer(rule & rule, xml_node const & sym)
 {
     debug_symbolizer symbol;
-
     parse_symbolizer_base(symbol, sym);
+    debug_symbolizer_mode_e mode =
+        sym.get_attr<debug_symbolizer_mode_e>("mode", DEBUG_SYM_MODE_COLLISION);
+    symbol.set_mode(mode);
     rule.append(symbol);
 }
 

src/xml_tree.cpp

@@ -405,6 +405,7 @@ compile_get_opt_attr(expression_ptr);
 compile_get_attr(std::string);
 compile_get_attr(filter_mode_e);
 compile_get_attr(point_placement_e);
+compile_get_attr(debug_symbolizer_mode_e);
 compile_get_attr(marker_placement_e);
 compile_get_attr(marker_multi_policy_e);
 compile_get_attr(pattern_alignment_e);

tests/data/good_maps/line_symbolizer.xml

@@ -6,7 +6,7 @@
       <LineSymbolizer stroke="white" stroke-gamma="0" stroke-width="10"/>
 
        <!-- small, clean, anti-aliased lines -->
-      <LineSymbolizer stroke="red" stroke-gamma="1" stroke-width=".5"/>
+      <DebugSymbolizer mode="vertex"/>
 
     </Rule>  
   </Style>

tests/python_tests/object_test.py

@@ -14,6 +14,10 @@ def setup():
     # from another directory we need to chdir()
     os.chdir(execution_path('.'))
 
+def test_debug_symbolizer():
+    s = mapnik.DebugSymbolizer()
+    eq_(s.mode,mapnik.debug_symbolizer_mode.collision)
+
 def test_raster_symbolizer():
     s = mapnik.RasterSymbolizer()
     eq_(s.comp_op,mapnik.CompositeOp.src_over) # note: mode is deprecated