first pass at a lower level set of clipping tests that avoid complexity of wkt and vertex converters - refs #1699

tests/cpp_tests/clipping_test.cpp

@@ -0,0 +1,123 @@
+
+// mapnik
+#include <mapnik/geometry.hpp>
+#include <mapnik/util/conversions.hpp>
+
+// boost
+#include <boost/detail/lightweight_test.hpp>
+#include <boost/algorithm/string.hpp>
+#include <boost/foreach.hpp>
+
+// stl
+#include <exception>
+#include <iostream>
+#include <fstream>
+#include <vector>
+
+// agg
+#include "agg_conv_clip_polygon.h"
+#include "agg_conv_clip_polyline.h"
+//#include "agg_path_storage.h"
+//#include "agg_conv_clipper.h"
+
+
+template <typename T>
+std::string dump_path(T & path)
+{
+    unsigned cmd = 1;
+    double x = 0;
+    double y = 0;
+    unsigned idx = 0;
+    std::ostringstream s;
+    path.rewind(0);
+    while ((cmd = path.vertex(&x, &y)) != mapnik::SEG_END)
+    {
+        if (idx > 0) s << ",";
+        s << x << " " << y << " " << cmd;
+        idx++;
+    }
+    return s.str();
+}
+
+std::string clip_line(mapnik::box2d<double> const& bbox,
+                      mapnik::geometry_type & geom)
+{
+    typedef agg::conv_clip_polyline<mapnik::geometry_type> line_clipper;
+    line_clipper clipped(geom);
+    clipped.clip_box(bbox.minx(),bbox.miny(),bbox.maxx(),bbox.maxy());
+    return dump_path(clipped);
+}
+
+void parse_geom(mapnik::geometry_type & geom,
+                std::string const& geom_string) {
+    std::vector<std::string> vertices;
+    boost::split(vertices, geom_string, boost::is_any_of(","));
+    BOOST_FOREACH(std::string const& vert, vertices)
+    {
+        std::vector<std::string> commands;
+        boost::split(commands, vert, boost::is_any_of(" "));
+        if (commands.size() != 3)
+        {
+            throw std::runtime_error(std::string("could not parse geometry '") + geom_string + "'");
+        }
+        double x = 0;
+        double y = 0;
+        int c = 0;
+        if (mapnik::util::string2double(commands[0],x)
+            && mapnik::util::string2double(commands[1],y)
+            && mapnik::util::string2int(commands[2],c))
+        {
+            geom.push_vertex(x,y,(mapnik::CommandType)c);
+        }
+        else
+        {
+            throw std::runtime_error(std::string("could not parse geometry '") + geom_string + "'");
+        }
+    }
+}
+
+int main( int, char*[] )
+{
+    try {
+        std::string filename("tests/cpp_tests/data/cases.txt");
+        std::ifstream stream(filename.c_str(),std::ios_base::in | std::ios_base::binary);
+        if (!stream.is_open())
+            throw std::runtime_error("could not open: '" + filename + "'");
+    
+        std::string csv_line;
+        while(std::getline(stream,csv_line,'\n'))
+        {
+            if (csv_line.empty() || csv_line[0] == '#') continue;
+            std::vector<std::string> parts;
+            boost::split(parts, csv_line, boost::is_any_of(";"));
+            // first part is clipping box
+            mapnik::box2d<double> bbox;
+            if (!bbox.from_string(parts[0])) {
+                throw std::runtime_error(std::string("could not parse bbox '") + parts[0] + "'");
+            }
+            // second part is input geometry
+            mapnik::geometry_type geom;
+            parse_geom(geom,parts[1]);
+            //std::clog << dump_path(geom) << "\n";
+            // third part is expected, clipped geometry
+            BOOST_TEST_EQ(clip_line(bbox,geom),parts[2]);
+        }
+        stream.close();
+    }
+    catch (std::exception const& ex)
+    {
+        std::cerr << ex.what() << "\n";
+    }
+
+    if (!::boost::detail::test_errors())
+    {
+        std::clog << "C++ clipping: \x1b[1;32m✓ \x1b[0m\n";
+#if BOOST_VERSION >= 104600
+        ::boost::detail::report_errors_remind().called_report_errors_function = true;
+#endif
+    }
+    else
+    {
+        return ::boost::report_errors();
+    }
+}

tests/cpp_tests/data/cases.txt

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+# testcase format is:
+# <bbox>;<input geometry>;<expected clipped geometry>
+# SEG_END=0 SEG_MOVETO = 1 SEG_LINETO = 2 SEG_CLOSE = (0x40 | 0x0f)
+50,50,150,150;0 0 1,200 200 2;50 50 1,150 150 2
+50,50,150,150;50 50 1,150 50 2,150 150 2,50 150 2,50 50 2;50 50 1,150 50 2,150 150 2,50 150 2,50 50 2
+# TODO - should the close path be kept after clipping?
+50,50,150,150;50 50 1,150 50 2,150 150 2,50 150 2,50 50 2,0 0 79;50 50 1,150 50 2,150 150 2,50 150 2,50 50 2, 0 0 79