Incomplete work for porting simplify() to XS

xs/src/ExPolygon.cpp

@@ -82,6 +82,32 @@ ExPolygon::contains_point(const Point* point) const
     return true;
 }
 
+Polygons
+ExPolygon::simplify(double tolerance) const
+{
+    Polygons p;
+    this->contour.simplify(tolerance, p);
+    for (Polygons::const_iterator it = this->holes.begin(); it != this->holes.end(); ++it)
+        it->simplify(tolerance, p);
+    simplify_polygons(p, p);
+    return p;
+}
+
+ExPolygons
+ExPolygon::simplify(double tolerance) const
+{
+    Polygons p = this->simplify(tolerance);
+    return union_(p);
+}
+
+void
+ExPolygon::simplify(double tolerance, ExPolygons &expolygons) const
+{
+    ExPolygons ep = this->simplify(tolerance);
+    expolygons.reserve(expolygons.size() + ep.size());
+    expolygons.insert(expolygons.end(), ep.begin(), ep.end());
+}
+
 #ifdef SLIC3RXS
 SV*
 ExPolygon::to_AV() {

xs/src/ExPolygon.hpp

@@ -19,6 +19,9 @@ class ExPolygon
     bool is_valid() const;
     bool contains_line(const Line* line) const;
     bool contains_point(const Point* point) const;
+    Polygons simplify(double tolerance) const;
+    ExPolygons simplify(double tolerance) const;
+    void simplify(double tolerance, ExPolygons &expolygons) const;
     
     #ifdef SLIC3RXS
     void from_SV(SV* poly_sv);

xs/src/ExPolygonCollection.cpp

@@ -47,4 +47,14 @@ ExPolygonCollection::contains_point(const Point* point) const
     return false;
 }
 
+void
+ExPolygonCollection::simplify(double tolerance)
+{
+    ExPolygons t;
+    for (ExPolygons::const_iterator it = this->expolygons.begin(); it != this->expolygons.end(); ++it) {
+        it->simplify_and_append_to(tolerance, t);
+    }
+    this->expolygons = t;
+}
+
 }

xs/src/ExPolygonCollection.hpp

@@ -15,6 +15,7 @@ class ExPolygonCollection
     void translate(double x, double y);
     void rotate(double angle, Point* center);
     bool contains_point(const Point* point) const;
+    void simplify(double tolerance);
 };
 
 }

xs/src/ExtrusionEntity.cpp

@@ -78,6 +78,12 @@ ExtrusionPath::clip_end(double distance)
     this->polyline.clip_end(distance);
 }
 
+void
+ExtrusionPath::simplify(double tolerance)
+{
+    this->polyline.simplify(tolerance);
+}
+
 double
 ExtrusionPath::length() const
 {

xs/src/ExtrusionEntity.hpp

@@ -54,6 +54,7 @@ class ExtrusionPath : public ExtrusionEntity
     ExtrusionEntityCollection* intersect_expolygons(ExPolygonCollection* collection) const;
     ExtrusionEntityCollection* subtract_expolygons(ExPolygonCollection* collection) const;
     void clip_end(double distance);
+    void simplify(double tolerance);
     double length() const;
     private:
     ExtrusionEntityCollection* _inflate_collection(const Polylines &polylines) const;

xs/src/MultiPoint.cpp

@@ -55,6 +55,47 @@ MultiPoint::is_valid() const
     return this->points.size() >= 2;
 }
 
+void
+MultiPoint::simplify(double tolerance)
+{
+    this->points = MultiPoint::_douglas_peucker(this->points, tolerance);
+}
+
+Points
+MultiPoint::_douglas_peucker(Points &points, double tolerance)
+{
+    Points results;
+    double dmax = 0;
+    int index = 0;
+    Line full(points.front(), points.back());
+    for (Points::const_iterator it = points.begin() + 1; it != points.end(); ++it) {
+        double d = it->distance_to(full);
+        if (d > dmax) {
+            index = it - points.begin();
+            dmax = d;
+        }
+    }
+    if (dmax >= tolerance) {
+        Points dp0;
+        dp0.reserve(index + 1);
+        dp0.insert(dp0.end(), points.begin(), points.begin() + index + 1);
+        Points dp1 = MultiPoint::_douglas_peucker(dp0, tolerance);
+        results.reserve(results.size() + dp1.size() - 1);
+        results.insert(results.end(), dp1.begin(), dp1.end() - 1);
+        
+        dp0.clear();
+        dp0.reserve(points.size() - index + 1);
+        dp0.insert(dp0.end(), points.begin() + index, points.end());
+        dp1 = MultiPoint::_douglas_peucker(dp0, tolerance);
+        results.reserve(results.size() + dp1.size());
+        results.insert(results.end(), dp1.begin(), dp1.end());
+    } else {
+        results.push_back(points.front());
+        results.push_back(points.back());
+    }
+    return results;
+}
+
 #ifdef SLIC3RXS
 void
 MultiPoint::from_SV(SV* poly_sv)

xs/src/MultiPoint.hpp

@@ -21,6 +21,7 @@ class MultiPoint
     virtual Lines lines() const = 0;
     double length() const;
     bool is_valid() const;
+    void simplify(double tolerance);
     
     #ifdef SLIC3RXS
     void from_SV(SV* poly_sv);
@@ -28,6 +29,9 @@ class MultiPoint
     SV* to_AV();
     SV* to_SV_pureperl() const;
     #endif
+    
+    private:
+    static Points _douglas_peucker(Points &points, double tolerance);
 };
 
 }

xs/src/Point.cpp

@@ -76,12 +76,18 @@ Point::distance_to(const Point* point) const
 double
 Point::distance_to(const Line* line) const
 {
-    if (line->a.coincides_with(&line->b)) return this->distance_to(&line->a);
+    return this->distance_to(*line);
+}
+
+double
+Point::distance_to(const Line &line) const
+{
+    if (line.a.coincides_with(&line.b)) return this->distance_to(&line.a);
     
-    double n = (line->b.x - line->a.x) * (line->a.y - this->y)
-        - (line->a.x - this->x) * (line->b.y - line->a.y);
+    double n = (line.b.x - line.a.x) * (line.a.y - this->y)
+        - (line.a.x - this->x) * (line.b.y - line.a.y);
     
-    return abs(n) / line->length();
+    return abs(n) / line.length();
 }
 
 #ifdef SLIC3RXS

xs/src/Point.hpp

@@ -25,6 +25,7 @@ class Point
     Point* nearest_point(Points points) const;
     double distance_to(const Point* point) const;
     double distance_to(const Line* line) const;
+    double distance_to(const Line &line) const;
     
     #ifdef SLIC3RXS
     void from_SV(SV* point_sv);

xs/src/Polygon.cpp

@@ -125,6 +125,12 @@ Polygon::contains_point(const Point* point) const
     return result;
 }
 
+Polygons
+Polygon::simplify(double tolerance) const
+{
+    
+}
+
 #ifdef SLIC3RXS
 SV*
 Polygon::to_SV_ref() {

xs/src/Polygon.hpp

@@ -24,6 +24,8 @@ class Polygon : public MultiPoint {
     bool make_clockwise();
     bool is_valid() const;
     bool contains_point(const Point* point) const;
+    Polygons simplify(double tolerance) const;
+    void simplify(double tolerance, Polygons &polygons) const;
     
     #ifdef SLIC3RXS
     SV* to_SV_ref();