feat: Segmentize for GeosCapi geometries.

History.md

@@ -6,6 +6,7 @@
 * Fix Naming/VariableNumber from rubocop_todos. (@haroon26) #351
 * Fix Lint/MissingSuper from rubocop_todos. (@haroon26) #352
 * Drop support for Ruby 2.6. (@seuros) #353
+* Add `segmentize` method to CAPI geometires (@arkirchner) #364
 
 **Bug Fixes**
 

ext/geos_c_impl/extconf.rb

@@ -45,6 +45,7 @@ def create_dummy_makefile
   have_func("GEOSPreparedDisjoint_r", "geos_c.h")
   have_func("GEOSUnaryUnion_r", "geos_c.h")
   have_func("GEOSCoordSeq_isCCW_r", "geos_c.h")
+  have_func("GEOSDensify", "geos_c.h")
   have_func("rb_memhash", "ruby.h")
   have_func("rb_gc_mark_movable", "ruby.h")
 end

ext/geos_c_impl/geometry.c

@@ -740,6 +740,27 @@ method_geometry_buffer(VALUE self, VALUE distance)
   return result;
 }
 
+#ifdef RGEO_GEOS_SUPPORTS_DENSIFY
+static VALUE
+method_geometry_segmentize(VALUE self, VALUE max_segment_length)
+{
+  VALUE result;
+  RGeo_GeometryData* self_data;
+  const GEOSGeometry* self_geom;
+  VALUE factory;
+
+  result = Qnil;
+  self_data = RGEO_GEOMETRY_DATA_PTR(self);
+  self_geom = self_data->geom;
+  if (self_geom) {
+    factory = self_data->factory;
+    result = rgeo_wrap_geos_geometry(
+      factory, GEOSDensify(self_geom, rb_num2dbl(max_segment_length)), Qnil);
+  }
+  return result;
+}
+#endif
+
 static VALUE
 method_geometry_buffer_with_style(VALUE self,
                                   VALUE distance,
@@ -1308,6 +1329,10 @@ rgeo_init_geos_geometry()
     geos_geometry_methods, "make_valid", method_geometry_make_valid, 0);
   rb_define_method(
     geos_geometry_methods, "polygonize", method_geometry_polygonize, 0);
+#ifdef RGEO_GEOS_SUPPORTS_DENSIFY
+  rb_define_method(
+    geos_geometry_methods, "segmentize", method_geometry_segmentize, 1);
+#endif
 }
 
 RGEO_END_C

ext/geos_c_impl/preface.h

@@ -23,6 +23,9 @@
 #ifdef HAVE_GEOSCOORDSEQ_ISCCW_R
 #define RGEO_GEOS_SUPPORTS_ISCCW
 #endif
+#ifdef HAVE_GEOSDENSIFY
+#define RGEO_GEOS_SUPPORTS_DENSIFY
+#endif
 #ifdef HAVE_RB_GC_MARK_MOVABLE
 #define mark rb_gc_mark_movable
 #else

test/geos_capi/line_string_test.rb

@@ -7,9 +7,11 @@
 # -----------------------------------------------------------------------------
 
 require_relative "../test_helper"
+require_relative "./skip_capi"
 
 class GeosLineStringTest < Minitest::Test # :nodoc:
   include RGeo::Tests::Common::LineStringTests
+  prepend SkipCAPI
 
   def setup
     skip "CAPI not supported" unless RGeo::Geos.capi_supported?
@@ -52,4 +54,17 @@ def test_polygonize_dangle
 
     assert_equal expected, input.polygonize
   end
+
+  def test_segmentize
+    skip_geos_version_less_then("3.10")
+
+    input = @factory.parse_wkt("LINESTRING(0 0, 0 10)")
+    expected = @factory.parse_wkt("LINESTRING (0 0, 0 5, 0 10)")
+
+    assert_equal expected, input.segmentize(5)
+
+    assert_raises(TypeError, "no implicit conversion to float from string") { input.segmentize("a") }
+    assert_raises(TypeError, "no implicit conversion to float from nil") { input.segmentize(nil) }
+    assert_raises(RGeo::Error::InvalidGeometry, "Tolerance must be positive") { input.segmentize(0) }
+  end
 end

test/geos_capi/polygon_test.rb

@@ -179,4 +179,17 @@ def test_polygonize
 
     assert_equal expected, input.polygonize
   end
+
+  def test_segmentize
+    skip_geos_version_less_then("3.10")
+
+    input = @factory.parse_wkt("POLYGON ((0 0, 10 0, 10 10, 0 10, 0 0))")
+    expected = @factory.parse_wkt("POLYGON ((0 0, 5 0, 10 0, 10 5, 10 10, 5 10, 0 10, 0 5, 0 0))")
+
+    assert_equal expected, input.segmentize(5)
+
+    assert_raises(TypeError, "no implicit conversion to float from string") { input.segmentize("a") }
+    assert_raises(TypeError, "no implicit conversion to float from nil") { input.segmentize(nil) }
+    assert_raises(RGeo::Error::InvalidGeometry, "Tolerance must be positive") { input.segmentize(0) }
+  end
 end

test/geos_capi/skip_capi.rb

@@ -5,4 +5,10 @@ def setup
     skip "Needs GEOS CAPI." unless RGeo::Geos.capi_supported?
     super
   end
+
+  def skip_geos_version_less_then(version)
+    return if Gem::Version.new(RGeo::Geos.version) >= Gem::Version.new(version)
+
+    skip "Needs GEOS version #{version} or later."
+  end
 end