Ported Polygon->is_counter_clockwise() and rearranged code in .cpp files

xs/src/ClipperUtils.cpp

@@ -0,0 +1,177 @@
+#include "ClipperUtils.hpp"
+
+namespace Slic3r {
+
+void
+ClipperPolygon_to_Slic3rPolygon(ClipperLib::Polygon &input, Slic3r::Polygon &output)
+{
+    output.points.clear();
+    for (ClipperLib::Polygon::iterator pit = input.begin(); pit != input.end(); ++pit) {
+        output.points.push_back(Slic3r::Point( (*pit).X, (*pit).Y ));
+    }
+}
+
+//-----------------------------------------------------------
+// legacy code from Clipper documentation
+void AddOuterPolyNodeToExPolygons(ClipperLib::PolyNode& polynode, Slic3r::ExPolygons& expolygons)
+{  
+  size_t cnt = expolygons.size();
+  expolygons.resize(cnt + 1);
+  ClipperPolygon_to_Slic3rPolygon(polynode.Contour, expolygons[cnt].contour);
+  expolygons[cnt].holes.resize(polynode.ChildCount());
+  for (int i = 0; i < polynode.ChildCount(); ++i)
+  {
+    ClipperPolygon_to_Slic3rPolygon(polynode.Childs[i]->Contour, expolygons[cnt].holes[i]);
+    //Add outer polygons contained by (nested within) holes ...
+    for (int j = 0; j < polynode.Childs[i]->ChildCount(); ++j)
+      AddOuterPolyNodeToExPolygons(*polynode.Childs[i]->Childs[j], expolygons);
+  }
+}
+ 
+void PolyTreeToExPolygons(ClipperLib::PolyTree& polytree, Slic3r::ExPolygons& expolygons)
+{
+  expolygons.clear();
+  for (int i = 0; i < polytree.ChildCount(); ++i)
+    AddOuterPolyNodeToExPolygons(*polytree.Childs[i], expolygons);
+}
+//-----------------------------------------------------------
+
+void
+Slic3rPolygon_to_ClipperPolygon(Slic3r::Polygon &input, ClipperLib::Polygon &output)
+{
+    output.clear();
+    for (Slic3r::Points::iterator pit = input.points.begin(); pit != input.points.end(); ++pit) {
+        output.push_back(ClipperLib::IntPoint( (*pit).x, (*pit).y ));
+    }
+}
+
+void
+Slic3rPolygons_to_ClipperPolygons(Slic3r::Polygons &input, ClipperLib::Polygons &output)
+{
+    output.clear();
+    for (Slic3r::Polygons::iterator it = input.begin(); it != input.end(); ++it) {
+        ClipperLib::Polygon p;
+        Slic3rPolygon_to_ClipperPolygon(*it, p);
+        output.push_back(p);
+    }
+}
+
+void
+ClipperPolygons_to_Slic3rExPolygons(ClipperLib::Polygons &input, Slic3r::ExPolygons &output)
+{
+    // init Clipper
+    ClipperLib::Clipper clipper;
+    clipper.Clear();
+    
+    // perform union
+    clipper.AddPolygons(input, ClipperLib::ptSubject);
+    ClipperLib::PolyTree* polytree = new ClipperLib::PolyTree();
+    clipper.Execute(ClipperLib::ctUnion, *polytree, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd);  // offset results work with both EvenOdd and NonZero
+    
+    // write to ExPolygons object
+    output.clear();
+    PolyTreeToExPolygons(*polytree, output);
+    
+    delete polytree;
+}
+
+void
+scaleClipperPolygons(ClipperLib::Polygons &polygons, const double scale)
+{
+    for (ClipperLib::Polygons::iterator it = polygons.begin(); it != polygons.end(); ++it) {
+        for (ClipperLib::Polygon::iterator pit = (*it).begin(); pit != (*it).end(); ++pit) {
+            (*pit).X *= scale;
+            (*pit).Y *= scale;
+        }
+    }
+}
+
+void
+offset_ex(Slic3r::Polygons &polygons, Slic3r::ExPolygons &retval, const float delta,
+    double scale, ClipperLib::JoinType joinType, double miterLimit)
+{
+    // read input
+    ClipperLib::Polygons* input = new ClipperLib::Polygons();
+    Slic3rPolygons_to_ClipperPolygons(polygons, *input);
+    
+    // scale input
+    scaleClipperPolygons(*input, scale);
+    
+    // perform offset
+    ClipperLib::Polygons* output = new ClipperLib::Polygons();
+    ClipperLib::OffsetPolygons(*input, *output, (delta*scale), joinType, miterLimit);
+    delete input;
+    
+    // unscale output
+    scaleClipperPolygons(*output, 1/scale);
+    
+    // convert into ExPolygons
+    ClipperPolygons_to_Slic3rExPolygons(*output, retval);
+    delete output;
+}
+
+void
+offset2_ex(Slic3r::Polygons &polygons, Slic3r::ExPolygons &retval, const float delta1,
+    const float delta2, double scale, ClipperLib::JoinType joinType, double miterLimit)
+{
+    // read input
+    ClipperLib::Polygons* input = new ClipperLib::Polygons();
+    Slic3rPolygons_to_ClipperPolygons(polygons, *input);
+    
+    // scale input
+    scaleClipperPolygons(*input, scale);
+    
+    // perform first offset
+    ClipperLib::Polygons* output1 = new ClipperLib::Polygons();
+    ClipperLib::OffsetPolygons(*input, *output1, (delta1*scale), joinType, miterLimit);
+    delete input;
+    
+    // perform second offset
+    ClipperLib::Polygons* output2 = new ClipperLib::Polygons();
+    ClipperLib::OffsetPolygons(*output1, *output2, (delta2*scale), joinType, miterLimit);
+    delete output1;
+    
+    // unscale output
+    scaleClipperPolygons(*output2, 1/scale);
+    
+    // convert into ExPolygons
+    ClipperPolygons_to_Slic3rExPolygons(*output2, retval);
+    delete output2;
+}
+
+void
+diff_ex(Slic3r::Polygons &subject, Slic3r::Polygons &clip, Slic3r::ExPolygons &retval, bool safety_offset)
+{
+    // read input
+    ClipperLib::Polygons* input_subject = new ClipperLib::Polygons();
+    ClipperLib::Polygons* input_clip    = new ClipperLib::Polygons();
+    Slic3rPolygons_to_ClipperPolygons(subject, *input_subject);
+    Slic3rPolygons_to_ClipperPolygons(clip,    *input_clip);
+    
+    // perform safety offset
+    if (safety_offset) {
+        // SafetyOffset(*input_clip);
+    }
+    
+    // init Clipper
+    ClipperLib::Clipper clipper;
+    clipper.Clear();
+    
+    // add polygons
+    clipper.AddPolygons(*input_subject, ClipperLib::ptSubject);
+    delete input_subject;
+    clipper.AddPolygons(*input_clip, ClipperLib::ptClip);
+    delete input_clip;
+    
+    // perform operation
+    ClipperLib::PolyTree* polytree = new ClipperLib::PolyTree();
+    clipper.Execute(ClipperLib::ctDifference, *polytree, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
+    
+    // convert into ExPolygons
+    PolyTreeToExPolygons(*polytree, retval);
+    delete polytree;
+}
+
+
+
+}