add support for spacing-offset

include/mapnik/markers_placements/basic.hpp

@@ -42,6 +42,7 @@ struct markers_placement_params
     box2d<double> size;
     agg::trans_affine tr;
     double spacing;
+    double spacing_offset;
     double max_error;
     bool allow_overlap;
     bool avoid_edges;

include/mapnik/markers_placements/line.hpp

@@ -43,10 +43,12 @@ public:
         : point_placement(locator, detector, params),
             first_point_(true),
             spacing_(0.0),
+            spacing_offset_(NAN),
             marker_width_((params.size * params.tr).width()),
             path_(locator)
     {
         spacing_ = params.spacing < 1 ? 100 : params.spacing;
+        spacing_offset_ = params.spacing_offset;
     }
 
     void rewind()
@@ -77,7 +79,7 @@ public:
                 return false;
             }
             first_point_ = false;
-            move = spacing_ / 2.0;
+            move = std::isnan(spacing_offset_) ? spacing_ / 2.0 : spacing_offset_;
         }
 
         while (path_.forward(move))
@@ -113,6 +115,7 @@ public:
 private:
     bool first_point_;
     double spacing_;
+    double spacing_offset_;
     double marker_width_;
     vertex_cache path_;
 };

include/mapnik/symbolizer_default_values.hpp

@@ -185,6 +185,13 @@ struct symbolizer_default<value_double, keys::spacing>
     static value_double value() { return 100.0; }
 };
 
+// spacing-offset
+template <>
+struct symbolizer_default<value_double, keys::spacing_offset>
+{
+    static value_double value() { return NAN; }
+};
+
 // max-error
 template <>
 struct symbolizer_default<value_double, keys::max_error>

include/mapnik/symbolizer_keys.hpp

@@ -52,6 +52,7 @@ enum class keys : std::uint8_t
     line_rasterizer,
     image_transform,
     spacing,
+    spacing_offset,
     max_error,
     allow_overlap,
     ignore_placement,

src/load_map.cpp

@@ -1124,6 +1124,7 @@ void map_parser::parse_markers_symbolizer(rule & rule, xml_node const& node)
         set_symbolizer_property<symbolizer_base,double>(sym, keys::opacity, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::fill_opacity, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::spacing, node);
+        set_symbolizer_property<symbolizer_base,double>(sym, keys::spacing_offset, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::max_error, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::offset, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::width, node);

src/renderer_common/render_markers_symbolizer.cpp

@@ -225,6 +225,7 @@ markers_dispatch_params::markers_dispatch_params(box2d<double> const& size,
         size,
         tr,
         get<value_double, keys::spacing>(sym, feature, vars),
+        get<value_double, keys::spacing_offset>(sym, feature, vars),
         get<value_double, keys::max_error>(sym, feature, vars),
         get<value_bool, keys::allow_overlap>(sym, feature, vars),
         get<value_bool, keys::avoid_edges>(sym, feature, vars),

src/symbolizer_keys.cpp

@@ -80,6 +80,7 @@ static const property_meta_type key_meta[const_max_key] =
                         property_types::target_double },
     property_meta_type{ "transform", nullptr, property_types::target_transform },
     property_meta_type{ "spacing", nullptr, property_types::target_double },
+    property_meta_type{ "spacing-offset", nullptr, property_types::target_double },
     property_meta_type{ "max-error", nullptr, property_types::target_double },
     property_meta_type{ "allow-overlap", nullptr, property_types::target_bool },
     property_meta_type{ "ignore-placement",  nullptr, property_types::target_bool },

test/unit/symbolizer/marker_placement_vertex_last.cpp

@@ -23,7 +23,7 @@ SECTION("empty geometry") {
     mapnik::markers_placement_params params {
         mapnik::box2d<double>(0, 0, 10, 10),
         agg::trans_affine(),
-        0, 0, false, false, DIRECTION_AUTO, 1.0 };
+        0, NAN, 0, false, false, DIRECTION_AUTO, 1.0 };
 
     placement_type placement(va, detector, params);
 
@@ -45,7 +45,7 @@ SECTION("point") {
     mapnik::markers_placement_params params {
         mapnik::box2d<double>(0, 0, 10, 10),
         agg::trans_affine(),
-        0, 0, false, false, DIRECTION_AUTO, 1.0 };
+        0, NAN, 0, false, false, DIRECTION_AUTO, 1.0 };
 
     placement_type placement(va, detector, params);
 
@@ -75,7 +75,7 @@ SECTION("line string") {
     mapnik::markers_placement_params params {
         mapnik::box2d<double>(0, 0, 10, 10),
         agg::trans_affine(),
-        0, 0, false, false, DIRECTION_AUTO, 1.0 };
+        0, NAN, 0, false, false, DIRECTION_AUTO, 1.0 };
 
     placement_type placement(va, detector, params);
 
@@ -109,7 +109,7 @@ SECTION("polygon") {
     mapnik::markers_placement_params params {
         mapnik::box2d<double>(0, 0, 10, 10),
         agg::trans_affine(),
-        0, 0, false, false, DIRECTION_AUTO, 1.0 };
+        0, NAN, 0, false, false, DIRECTION_AUTO, 1.0 };
 
     placement_type placement(va, detector, params);
 

test/unit/symbolizer/markers_point_placement.cpp

@@ -23,7 +23,7 @@ SECTION("empty geometry") {
     mapnik::markers_placement_params params {
         mapnik::box2d<double>(0, 0, 10, 10),
         agg::trans_affine(),
-        0, 0, false, false, DIRECTION_AUTO, 1.0 };
+        0, NAN, 0, false, false, DIRECTION_AUTO, 1.0 };
 
     placement_type placement(va, detector, params);
 
@@ -45,7 +45,7 @@ SECTION("point") {
     mapnik::markers_placement_params params {
         mapnik::box2d<double>(0, 0, 10, 10),
         agg::trans_affine(),
-        0, 0, false, false, DIRECTION_AUTO, 1.0 };
+        0, NAN, 0, false, false, DIRECTION_AUTO, 1.0 };
 
     placement_type placement(va, detector, params);
 
@@ -75,7 +75,7 @@ SECTION("line string") {
     mapnik::markers_placement_params params {
         mapnik::box2d<double>(0, 0, 10, 10),
         agg::trans_affine(),
-        0, 0, false, false, DIRECTION_AUTO, 1.0 };
+        0, NAN, 0, false, false, DIRECTION_AUTO, 1.0 };
 
     placement_type placement(va, detector, params);
 
@@ -105,7 +105,7 @@ SECTION("line string zero length") {
     mapnik::markers_placement_params params {
         mapnik::box2d<double>(0, 0, 10, 10),
         agg::trans_affine(),
-        0, 0, false, false, DIRECTION_AUTO, 1.0 };
+        0, NAN, 0, false, false, DIRECTION_AUTO, 1.0 };
 
     placement_type placement(va, detector, params);
 
@@ -119,4 +119,4 @@ SECTION("line string zero length") {
     CHECK( !placement.get_point(x, y, angle, true) );
 }
 
-}
+}