Working arrange_objects with DJD selection heuristic and a bottom-left placement strategy.

xs/src/libnest2d/libnest2d/clipper_backend/clipper_backend.cpp

@@ -0,0 +1,77 @@
+#include "clipper_backend.hpp"
+
+namespace libnest2d {
+
+namespace  {
+class HoleCache {
+    friend struct libnest2d::ShapeLike;
+
+    std::unordered_map< const PolygonImpl*, ClipperLib::Paths> map;
+
+    ClipperLib::Paths& _getHoles(const PolygonImpl* p) {
+        ClipperLib::Paths& paths = map[p];
+
+        if(paths.size() != p->Childs.size()) {
+            paths.reserve(p->Childs.size());
+
+            for(auto np : p->Childs) {
+                paths.emplace_back(np->Contour);
+            }
+        }
+
+        return paths;
+    }
+
+    ClipperLib::Paths& getHoles(PolygonImpl& p) {
+        return _getHoles(&p);
+    }
+
+    const ClipperLib::Paths& getHoles(const PolygonImpl& p) {
+        return _getHoles(&p);
+    }
+};
+}
+
+HoleCache holeCache;
+
+template<>
+std::string ShapeLike::toString(const PolygonImpl& sh)
+{
+   std::stringstream ss;
+
+   for(auto p : sh.Contour) {
+       ss << p.X << " " << p.Y << "\n";
+   }
+
+   return ss.str();
+}
+
+template<> PolygonImpl ShapeLike::create( std::initializer_list< PointImpl > il)
+{
+    PolygonImpl p;
+    p.Contour = il;
+
+    // Expecting that the coordinate system Y axis is positive in upwards
+    // direction
+    if(ClipperLib::Orientation(p.Contour)) {
+        // Not clockwise then reverse the b*tch
+        ClipperLib::ReversePath(p.Contour);
+    }
+
+    return p;
+}
+
+template<>
+const THolesContainer<PolygonImpl>& ShapeLike::holes(
+        const PolygonImpl& sh)
+{
+    return holeCache.getHoles(sh);
+}
+
+template<>
+THolesContainer<PolygonImpl>& ShapeLike::holes(PolygonImpl& sh) {
+    return holeCache.getHoles(sh);
+}
+
+}
+