Ported encloses_point() to XS and renamed to contains_point()

xs/src/ExPolygon.cpp

@@ -62,7 +62,7 @@ ExPolygon::is_valid() const
 }
 
 bool
-ExPolygon::contains_line(Line* line) const
+ExPolygon::contains_line(const Line* line) const
 {
     Polylines pl(1);
     pl.push_back(*line);
@@ -72,6 +72,16 @@ ExPolygon::contains_line(Line* line) const
     return pl_out.empty();
 }
 
+bool
+ExPolygon::contains_point(const Point* point) const
+{
+    if (!this->contour.contains_point(point)) return false;
+    for (Polygons::const_iterator it = this->holes.begin(); it != this->holes.end(); ++it) {
+        if (it->contains_point(point)) return false;
+    }
+    return true;
+}
+
 #ifdef SLIC3RXS
 SV*
 ExPolygon::to_AV() {

xs/src/ExPolygon.hpp

@@ -17,7 +17,8 @@ class ExPolygon
     void rotate(double angle, Point* center);
     double area() const;
     bool is_valid() const;
-    bool contains_line(Line* line) const;
+    bool contains_line(const Line* line) const;
+    bool contains_point(const Point* point) const;
     
     #ifdef SLIC3RXS
     void from_SV(SV* poly_sv);

xs/src/Polygon.cpp

@@ -110,6 +110,21 @@ Polygon::is_valid() const
     return this->points.size() >= 3;
 }
 
+bool
+Polygon::contains_point(const Point* point) const
+{
+    // http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
+    bool result;
+    Points::const_iterator i = this->points.begin();
+    Points::const_iterator j = this->points.end() - 1;
+    for (; i != this->points.end(); j = i++) {
+        if ( ((i->y > point->y) != (j->y > point->y))
+            && (point->x < (j->x - i->x) * (point->y - i->y) / (j->y - i->y) + i->x) )
+            result = !result;
+    }
+    return result;
+}
+
 #ifdef SLIC3RXS
 SV*
 Polygon::to_SV_ref() {

xs/src/Polygon.hpp

@@ -23,6 +23,7 @@ class Polygon : public MultiPoint {
     bool make_counter_clockwise();
     bool make_clockwise();
     bool is_valid() const;
+    bool contains_point(const Point* point) const;
     
     #ifdef SLIC3RXS
     SV* to_SV_ref();

xs/src/PolylineCollection.cpp

@@ -49,6 +49,7 @@ PolylineCollection::leftmost_point() const
         if (p == NULL || it->points.front().x < p->x)
             p = &(it->points.front());
     }
+    if (p == NULL) return NULL;
     return new Point (*p);
 }