Updating libdepixelize.

This update is not focused on new features, but on stability.

Bugs affecting weird image sizes (single line or single row images) were
fixed.

A bug on algorithm that could cause wrong result of heuristics on very
rare images was also fixed. The correct behaviour required storing all
votes before really doing any removal and this extra work made this step
of the algorithm 328% slower on one sample image. If the old *_safe
function was used, the slowdown could be decreased to 7.7% on the same
sample image, but current focus on Inkscape timeline is stabilization,
then I'll delay performance optimization to later. Also, the affected
step is only responsible for 18% (on the maximum case) of the
performance. The performance tests were done using new profiling code
that is disabled by default and shouldn't impact stability.

(bzr r13209)

3 files changed, 326 insertions, 46 deletions

diff --git a/src/libdepixelize/priv/homogeneoussplines.h b/src/libdepixelize/priv/homogeneoussplines.h
index 57c77a163..6c4894dd8 100644
--- a/src/libdepixelize/priv/homogeneoussplines.h
+++ b/src/libdepixelize/priv/homogeneoussplines.h
@@ -38,6 +38,12 @@ class HomogeneousSplines
 public:
     struct Polygon
     {
+        typedef std::vector< Point<T> > Points;
+        typedef typename Points::iterator points_iter;
+        typedef typename Points::const_iterator const_points_iter;
+        typedef typename std::vector<Points>::iterator holes_iter;
+        typedef typename std::vector<Points>::const_iterator const_holes_iter;
+
         Polygon() {}
         Polygon(const guint8 (&rgba)[4])
         {
@@ -59,7 +65,8 @@ public:
     typedef typename std::vector<Polygon>::const_iterator const_iterator;
     typedef typename std::vector<Polygon>::size_type size_type;
 
-    HomogeneousSplines(const SimplifiedVoronoi<T> &voronoi);
+    template<bool adjust_splines>
+    HomogeneousSplines(const SimplifiedVoronoi<T, adjust_splines> &voronoi);
 
     // Iterators
     iterator begin()
@@ -98,12 +105,7 @@ public:
     }
 
 private:
-    typedef typename SimplifiedVoronoi<T>::Cell Cell;
     typedef std::vector< Point<T> > Points;
-
-    typedef typename SimplifiedVoronoi<T>::iterator voronoi_iter;
-    typedef typename SimplifiedVoronoi<T>::const_iterator voronoi_citer;
-
     typedef typename Points::iterator points_iter;
     typedef typename Points::const_iterator points_citer;
     typedef typename Points::reverse_iterator points_riter;
@@ -171,7 +173,9 @@ private:
 };
 
 template<class T>
-HomogeneousSplines<T>::HomogeneousSplines(const SimplifiedVoronoi<T> &voronoi) :
+template<bool adjust_splines>
+HomogeneousSplines<T>::HomogeneousSplines(const SimplifiedVoronoi<T,
+                                          adjust_splines> &voronoi) :
     _width(voronoi.width()),
     _height(voronoi.height())
 {
@@ -179,6 +183,9 @@ HomogeneousSplines<T>::HomogeneousSplines(const SimplifiedVoronoi<T> &voronoi) :
     //    return;
     using colorspace::same_color;
 
+    typedef typename SimplifiedVoronoi<T, adjust_splines>::const_iterator
+        voronoi_citer;
+
     // Identify visible edges (group polygons with the same color)
     for ( voronoi_citer cell_it = voronoi.begin(), cell_end = voronoi.end()
               ; cell_it != cell_end ; ++cell_it ) {
diff --git a/src/libdepixelize/priv/pixelgraph.h b/src/libdepixelize/priv/pixelgraph.h
index 9e8c2124a..112242647 100644
--- a/src/libdepixelize/priv/pixelgraph.h
+++ b/src/libdepixelize/priv/pixelgraph.h
@@ -28,6 +28,7 @@
 #include <gdkmm/pixbuf.h>
 #include <vector>
 #include <cassert>
+#include <utility>
 
 namespace Tracer {
 
@@ -76,6 +77,10 @@ public:
     typedef std::vector<Node>::reverse_iterator reverse_iterator;
     typedef std::vector<Node>::const_reverse_iterator const_reverse_iterator;
 
+    typedef std::pair<iterator, iterator> Edge;
+    typedef std::pair<Edge, Edge> EdgePair;
+    typedef std::vector<EdgePair> EdgePairContainer;
+
     class ColumnView
     {
     public:
@@ -162,6 +167,7 @@ public:
 
     // Algorithms
     void connectAllNeighbors();
+    EdgePairContainer crossingEdges();
 
     int toX(const_iterator n) const
     {
@@ -389,14 +395,23 @@ inline void PixelGraph::connectAllNeighbors()
     //  ...then the "top" nodes...
     if ( _width > 2 ) {
         Node *it = &_nodes[1];
-        for ( int i = 1 ; i != _width - 1 ; ++i ) {
-            it->adj.right = 1;
-            it->adj.bottomright = 1;
-            it->adj.bottom = 1;
-            it->adj.bottomleft = 1;
-            it->adj.left = 1;
+        if ( _height > 1 ) {
+            for ( int i = 1 ; i != _width - 1 ; ++i ) {
+                it->adj.right = 1;
+                it->adj.bottomright = 1;
+                it->adj.bottom = 1;
+                it->adj.bottomleft = 1;
+                it->adj.left = 1;
 
-            ++it;
+                ++it;
+            }
+        } else {
+            for ( int i = 1 ; i != _width - 1 ; ++i ) {
+                it->adj.right = 1;
+                it->adj.left = 1;
+
+                ++it;
+            }
         }
     }
 
@@ -417,14 +432,23 @@ inline void PixelGraph::connectAllNeighbors()
     //  ...then the "left" nodes...
     if ( _height > 2 ) {
         iterator it = nodeBottom(begin()); // [0][1]
-        for ( int i = 1 ; i != _height - 1 ; ++i ) {
-            it->adj.top = 1;
-            it->adj.topright = 1;
-            it->adj.right = 1;
-            it->adj.bottomright = 1;
-            it->adj.bottom = 1;
+        if ( _width > 1 ) {
+            for ( int i = 1 ; i != _height - 1 ; ++i ) {
+                it->adj.top = 1;
+                it->adj.topright = 1;
+                it->adj.right = 1;
+                it->adj.bottomright = 1;
+                it->adj.bottom = 1;
 
-            it = nodeBottom(it);
+                it = nodeBottom(it);
+            }
+        } else {
+            for ( int i = 1 ; i != _height - 1 ; ++i ) {
+                it->adj.top = 1;
+                it->adj.bottom = 1;
+
+                it = nodeBottom(it);
+            }
         }
     }
 
@@ -482,6 +506,34 @@ inline void PixelGraph::connectAllNeighbors()
     }
 }
 
+PixelGraph::EdgePairContainer PixelGraph::crossingEdges()
+{
+    EdgePairContainer ret;
+
+    if ( width() < 2 || height() < 2 )
+        return ret;
+
+    // Iterate over the graph, 2x2 blocks at time
+    PixelGraph::iterator it = begin();
+    for (int i = 0 ; i != height() - 1 ; ++i, ++it ) {
+        for ( int j = 0 ; j != width() - 1 ; ++j, ++it ) {
+            EdgePair diagonals(
+                Edge(it, nodeBottomRight(it)),
+                Edge(nodeRight(it), nodeBottom(it)));
+
+            // Check if there are crossing edges
+            if ( !diagonals.first.first->adj.bottomright
+                 || !diagonals.second.first->adj.bottomleft ) {
+                continue;
+            }
+
+            ret.push_back(diagonals);
+        }
+    }
+
+    return ret;
+}
+
 inline PixelGraph::Node &PixelGraph::ColumnView::operator[](int line)
 {
     return _nodes[line * _width + _column];
diff --git a/src/libdepixelize/priv/simplifiedvoronoi.h b/src/libdepixelize/priv/simplifiedvoronoi.h
index 8a25bc626..84feab08d 100644
--- a/src/libdepixelize/priv/simplifiedvoronoi.h
+++ b/src/libdepixelize/priv/simplifiedvoronoi.h
@@ -296,21 +296,40 @@ SimplifiedVoronoi<T, adjust_splines>
         PixelGraph::const_iterator graph_it = graph.begin() + 1;
         Cell *cells_it = &_cells.front() + 1;
 
-        for ( int i = 1 ; i != _width - 1 ; ++i, ++graph_it, ++cells_it ) {
-            for ( int j = 0 ; j != 4 ; ++j )
-                cells_it->rgba[j] = graph_it->rgba[j];
+        if ( _height > 1 ) {
+            for ( int i = 1 ; i != _width - 1 ; ++i, ++graph_it, ++cells_it ) {
+                for ( int j = 0 ; j != 4 ; ++j )
+                    cells_it->rgba[j] = graph_it->rgba[j];
 
-            // Top-left
-            cells_it->vertices.push_back(Point<T>(i, 0, false));
+                // Top-left
+                cells_it->vertices.push_back(Point<T>(i, 0, false));
 
-            // Top-right
-            cells_it->vertices.push_back(Point<T>(i + 1, 0, false));
+                // Top-right
+                cells_it->vertices.push_back(Point<T>(i + 1, 0, false));
 
-            // Bottom-right
-            _complexBottomRight(graph, graph_it, cells_it, i, 0);
+                // Bottom-right
+                _complexBottomRight(graph, graph_it, cells_it, i, 0);
 
-            // Bottom-left
-            _complexBottomLeft(graph, graph_it, cells_it, i, 0);
+                // Bottom-left
+                _complexBottomLeft(graph, graph_it, cells_it, i, 0);
+            }
+        } else {
+            for ( int i = 1 ; i != _width - 1 ; ++i, ++graph_it, ++cells_it ) {
+                for ( int j = 0 ; j != 4 ; ++j )
+                    cells_it->rgba[j] = graph_it->rgba[j];
+
+                // Top-left
+                cells_it->vertices.push_back(Point<T>(i, 0, false));
+
+                // Top-right
+                cells_it->vertices.push_back(Point<T>(i + 1, 0, false));
+
+                // Bottom-right
+                cells_it->vertices.push_back(Point<T>(i + 1, 1, false));
+
+                // Bottom-left
+                cells_it->vertices.push_back(Point<T>(i, 1, false));
+            }
         }
     }
 
@@ -344,24 +363,46 @@ SimplifiedVoronoi<T, adjust_splines>
         PixelGraph::const_iterator graph_it = graph.begin() + _width;
         Cell *cells_it = &_cells.front() + _width;
 
-        for ( int i = 1 ; i != _height - 1 ; ++i) {
-            for ( int j = 0 ; j != 4 ; ++j )
-                cells_it->rgba[j] = graph_it->rgba[j];
+        if ( _width > 1 ) {
+            for ( int i = 1 ; i != _height - 1 ; ++i) {
+                for ( int j = 0 ; j != 4 ; ++j )
+                    cells_it->rgba[j] = graph_it->rgba[j];
 
-            // Top-left
-            cells_it->vertices.push_back(Point<T>(0, i, false));
+                // Top-left
+                cells_it->vertices.push_back(Point<T>(0, i, false));
 
-            // Top-right
-            _complexTopRight(graph, graph_it, cells_it, 0, i);
+                // Top-right
+                _complexTopRight(graph, graph_it, cells_it, 0, i);
 
-            // Bottom-right
-            _complexBottomRight(graph, graph_it, cells_it, 0, i);
+                // Bottom-right
+                _complexBottomRight(graph, graph_it, cells_it, 0, i);
 
-            // Bottom-left
-            cells_it->vertices.push_back(Point<T>(0, i + 1, false));
+                // Bottom-left
+                cells_it->vertices.push_back(Point<T>(0, i + 1, false));
 
-            graph_it += _width;
-            cells_it += _width;
+                graph_it += _width;
+                cells_it += _width;
+            }
+        } else {
+            for ( int i = 1 ; i != _height - 1 ; ++i) {
+                for ( int j = 0 ; j != 4 ; ++j )
+                    cells_it->rgba[j] = graph_it->rgba[j];
+
+                // Top-left
+                cells_it->vertices.push_back(Point<T>(0, i, false));
+
+                // Top-right
+                cells_it->vertices.push_back(Point<T>(1, i, false));
+
+                // Bottom-right
+                cells_it->vertices.push_back(Point<T>(1, i, false));
+
+                // Bottom-left
+                cells_it->vertices.push_back(Point<T>(0, i + 1, false));
+
+                graph_it += _width;
+                cells_it += _width;
+            }
         }
     }
 
@@ -890,7 +931,11 @@ SimplifiedVoronoi<T, adjust_splines>
         }
 
         if ( !smooth[0] && adjust_splines ) {
-            cells_it->vertices.push_back(vertices[0].invisible());
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
+           cells_it->vertices.push_back(vertices[0].invisible());
+#else
+           cells_it->vertices.push_back(vertices[0]);
+#endif
             {
                 Point<T> another = vertices[0];
                 transform(another,
@@ -899,7 +944,11 @@ SimplifiedVoronoi<T, adjust_splines>
                           // y
                           - ( 0.5625
                               - ( topright(a_it) + topleft(b_it) ) * 0.1875 ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                 cells_it->vertices.push_back(another.invisible());
+#else
+                cells_it->vertices.push_back(another);
+#endif
             }
             {
                 Point<T> another = vertices[0];
@@ -910,7 +959,11 @@ SimplifiedVoronoi<T, adjust_splines>
                           - ( 0.1875
                               - ( topright(a_it) + topleft(b_it) ) * 0.0625) );
                 another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                cells_it->vertices.push_back(another.invisible());
+#else
                 cells_it->vertices.push_back(another);
+#endif
             }
             {
                 Point<T> another = vertices[0];
@@ -920,7 +973,11 @@ SimplifiedVoronoi<T, adjust_splines>
                           // y
                           0.0625
                           + ( bottomright(b_it) - topright(d_it) ) * 0.0625);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                 cells_it->vertices.push_back(another.invisible());
+#else
+                cells_it->vertices.push_back(another);
+#endif
             }
             {
                 transform(vertices[0],
@@ -932,7 +989,9 @@ SimplifiedVoronoi<T, adjust_splines>
                               + ( topright(d_it) - topright(a_it)
                                   - topleft(b_it) - bottomright(b_it) )
                               * 0.03125 ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                 vertices[0].visible = false;
+#endif
             }
         }
 
@@ -950,7 +1009,11 @@ SimplifiedVoronoi<T, adjust_splines>
                           0.0625
                           + ( bottomleft(a_it) - bottomleft(d_it)
                               - topleft(c_it) - bottomright(c_it) ) * 0.03125);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                 cells_it->vertices.push_back(another.invisible());
+#else
+                cells_it->vertices.push_back(another);
+#endif
             }
             {
                 Point<T> another = vertices[1];
@@ -960,7 +1023,11 @@ SimplifiedVoronoi<T, adjust_splines>
                           // y
                           0.1875
                           - ( bottomright(c_it) + bottomleft(d_it) ) * 0.0625);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                 cells_it->vertices.push_back(another.invisible());
+#else
+                cells_it->vertices.push_back(another);
+#endif
             }
             {
                 Point<T> another = vertices[1];
@@ -973,7 +1040,11 @@ SimplifiedVoronoi<T, adjust_splines>
                               - ( bottomleft(a_it) - topleft(c_it) )
                               * 0.0625 ));
                 another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                cells_it->vertices.push_back(another.invisible());
+#else
                 cells_it->vertices.push_back(another);
+#endif
             }
             {
                 Point<T> another = vertices[1];
@@ -985,9 +1056,15 @@ SimplifiedVoronoi<T, adjust_splines>
                           - ( 0.1875
                               - ( bottomleft(a_it) - topleft(c_it) )
                               * 0.1875 ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                 cells_it->vertices.push_back(another.invisible());
+#else
+                cells_it->vertices.push_back(another);
+#endif
             }
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
             vertices[1].visible = false;
+#endif
         }
 
         cells_it->vertices.push_back(vertices[1]);
@@ -1029,13 +1106,21 @@ SimplifiedVoronoi<T, adjust_splines>
                                     - ( ( bottomright(c_it) + topleft(c_it) )
                                         * 0.03125 );
                                 transform(another, - amount, amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                                 cells_it->vertices.push_back(another.invisible());
+#else
+                                cells_it->vertices.push_back(another);
+#endif
                             }
                             {
                                 Point<T> another = vertex;
                                 T amount = 0.0625 * bottomright(c_it);
                                 transform(another, amount, 0.25 - amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                                 cells_it->vertices.push_back(another.invisible());
+#else
+                                cells_it->vertices.push_back(another);
+#endif
                             }
                             {
                                 Point<T> another = vertex;
@@ -1043,16 +1128,26 @@ SimplifiedVoronoi<T, adjust_splines>
                                 transform(another, - ( 0.25 - amount ),
                                           - amount);
                                 another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                                cells_it->vertices.push_back(another.invisible());
+#else
                                 cells_it->vertices.push_back(another);
+#endif
                             }
                             {
                                 Point<T> another = vertex;
                                 T amount = 0.1875 * topleft(c_it);
                                 transform(another, - ( 0.75 - amount ),
                                           - amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                                 cells_it->vertices.push_back(another.invisible());
+#else
+                                cells_it->vertices.push_back(another);
+#endif
                             }
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                             vertex.visible = false;
+#endif
                         } else if ( twin_is_contour ) {
                             T amount = 0.125
                                 - ( ( bottomleft(d_it) + topright(d_it) )
@@ -1076,7 +1171,11 @@ SimplifiedVoronoi<T, adjust_splines>
                                       - amount
                                       * ( topleft(c_it) + topright(d_it)
                                           - bottomleft(a_it) - bottomright(b_it) ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
@@ -1087,7 +1186,11 @@ SimplifiedVoronoi<T, adjust_splines>
                                       // y
                                       - amount
                                       * ( topright(d_it) - bottomright(b_it) ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
@@ -1099,7 +1202,11 @@ SimplifiedVoronoi<T, adjust_splines>
                                       - amount
                                       * ( topleft(c_it) - bottomleft(a_it) ));
                             another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                            cells_it->vertices.push_back(another.invisible());
+#else
                             cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
@@ -1110,9 +1217,15 @@ SimplifiedVoronoi<T, adjust_splines>
                                       // y
                                       -  amount
                                       * ( topleft(c_it) - bottomleft(a_it) ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                         vertex.visible = false;
+#endif
                     }
                 } else {
                     // {this, right} is the pair with the angle
@@ -1146,13 +1259,21 @@ SimplifiedVoronoi<T, adjust_splines>
 
                     if ( !vertex.smooth ) {
                         if ( another_is_contour ) {
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                             cells_it->vertices.push_back(vertex.invisible());
+#else
+                            cells_it->vertices.push_back(vertex);
+#endif
                             {
                                 Point<T> another = vertex;
                                 T amount = 0.1875 * topleft(b_it);
                                 transform(another, - amount,
                                           - ( 0.75 - amount ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                                 cells_it->vertices.push_back(another.invisible());
+#else
+                                cells_it->vertices.push_back(another);
+#endif
                             }
                             {
                                 Point<T> another = vertex;
@@ -1160,20 +1281,30 @@ SimplifiedVoronoi<T, adjust_splines>
                                 transform(another, - amount,
                                           - ( 0.25 - amount ));
                                 another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                                cells_it->vertices.push_back(another.invisible());
+#else
                                 cells_it->vertices.push_back(another);
+#endif
                             }
                             {
                                 Point<T> another = vertex;
                                 T amount = 0.0625 * bottomright(b_it);
                                 transform(another, 0.25 - amount, amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                                 cells_it->vertices.push_back(another.invisible());
+#else
+                                cells_it->vertices.push_back(another);
+#endif
                             }
                             {
                                 T amount = 0.125
                                     - (bottomright(b_it) + topleft(b_it))
                                     * 0.03125;
                                 transform(vertex, amount, - amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                                 vertex.visible = false;
+#endif
                             }
                         } else if ( twin_is_contour ) {
                             T amount = 0.125
@@ -1187,7 +1318,11 @@ SimplifiedVoronoi<T, adjust_splines>
                         // I REALLY NEED lambdas to improve this code without
                         // creating yet another interface that takes a million
                         // of function parameters and keep code locality
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                         cells_it->vertices.push_back(vertex.invisible());
+#else
+                        cells_it->vertices.push_back(vertex);
+#endif
                         {
                             Point<T> another = vertex;
                             T amount = 0.1875;
@@ -1197,7 +1332,11 @@ SimplifiedVoronoi<T, adjust_splines>
                                       - ( 0.75
                                           - ( topleft(b_it) + topright(a_it) )
                                           * amount ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
@@ -1209,7 +1348,11 @@ SimplifiedVoronoi<T, adjust_splines>
                                           - ( topleft(b_it) + topright(a_it) )
                                           * amount ));
                             another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                            cells_it->vertices.push_back(another.invisible());
+#else
                             cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
@@ -1219,7 +1362,11 @@ SimplifiedVoronoi<T, adjust_splines>
                                       // y
                                       0.25 - amount
                                       * ( bottomleft(d_it) + bottomright(c_it) ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             transform(vertex,
@@ -1230,7 +1377,9 @@ SimplifiedVoronoi<T, adjust_splines>
                                       ( topleft(b_it) - bottomleft(d_it)
                                         + topright(a_it) - bottomright(c_it) )
                                       * 0.03125);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                             vertex.visible = false;
+#endif
                         }
                     }
                 } else {
@@ -1273,28 +1422,46 @@ SimplifiedVoronoi<T, adjust_splines>
                                 - ( topleft(c_it) + bottomright(c_it) )
                                 * 0.03125;
                             transform(another, - amount, amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
                             T amount = 0.0625 * bottomright(c_it);
                             transform(another, amount, 0.25 - amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
                             T amount = 0.0625 * topleft(c_it);
                             transform(another, - ( 0.25 - amount ), - amount);
                             another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                            cells_it->vertices.push_back(another.invisible());
+#else
                             cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
                             T amount = 0.1875 * topleft(c_it);
                             transform(another, - ( 0.75 - amount ), - amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                         vertex.visible = false;
+#endif
                     } else {
                         special = true;
                     }
@@ -1308,7 +1475,11 @@ SimplifiedVoronoi<T, adjust_splines>
             }
 
             if ( special ) {
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                 cells_it->vertices.push_back(vertex.invisible());
+#else
+                cells_it->vertices.push_back(vertex);
+#endif
                 {
                     Point<T> another = vertex;
                     T amount = 0.1875;
@@ -1318,7 +1489,11 @@ SimplifiedVoronoi<T, adjust_splines>
                               - ( 0.75
                                   - ( topleft(b_it) + topright(a_it) )
                                   * amount ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                     cells_it->vertices.push_back(another.invisible());
+#else
+                    cells_it->vertices.push_back(another);
+#endif
                 }
                 {
                     Point<T> another = vertex;
@@ -1330,7 +1505,11 @@ SimplifiedVoronoi<T, adjust_splines>
                                   - ( topleft(b_it) + topright(a_it) )
                                   * amount ));
                     another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                    cells_it->vertices.push_back(another.invisible());
+#else
                     cells_it->vertices.push_back(another);
+#endif
                 }
                 {
                     Point<T> another = vertex;
@@ -1340,7 +1519,11 @@ SimplifiedVoronoi<T, adjust_splines>
                               // y
                               0.25 - amount
                               * ( bottomleft(d_it) + bottomright(c_it) ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                     cells_it->vertices.push_back(another.invisible());
+#else
+                    cells_it->vertices.push_back(another);
+#endif
                 }
                 {
                     transform(vertex,
@@ -1351,7 +1534,9 @@ SimplifiedVoronoi<T, adjust_splines>
                               ( topleft(b_it) - bottomleft(d_it)
                                 + topright(a_it) - bottomright(c_it) )
                               * 0.03125);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                     vertex.visible = false;
+#endif
                 }
             }
         } else if ( right(c_it) && adjust_splines ) {
@@ -1372,31 +1557,49 @@ SimplifiedVoronoi<T, adjust_splines>
 
                 if ( !vertex.smooth ) {
                     if ( similar_neighbor_is_contour ) {
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                         cells_it->vertices.push_back(vertex.invisible());
+#else
+                        cells_it->vertices.push_back(vertex);
+#endif
                         {
                             Point<T> another = vertex;
                             T amount = 0.1875 * topleft(b_it);
                             transform(another, - amount, - ( 0.75 - amount ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
                             T amount = 0.0625 * topleft(b_it);
                             transform(another, - amount, - ( 0.25 - amount ));
                             another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                            cells_it->vertices.push_back(another.invisible());
+#else
                             cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             Point<T> another = vertex;
                             T amount = 0.0625 * bottomright(b_it);
                             transform(another, 0.25 - amount, amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                             cells_it->vertices.push_back(another.invisible());
+#else
+                            cells_it->vertices.push_back(another);
+#endif
                         }
                         {
                             T amount = 0.125
                                 - 0.03125 * (topleft(b_it) + bottomright(b_it));
                             transform(vertex, amount, - amount);
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                             vertex.visible = false;
+#endif
                         }
                     } else {
                         special = true;
@@ -1422,7 +1625,11 @@ SimplifiedVoronoi<T, adjust_splines>
                               - amount
                               * ( topleft(c_it) + topright(d_it)
                                   - bottomleft(a_it) - bottomright(b_it) ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_1ST_IS_INVISIBLE
                     cells_it->vertices.push_back(another.invisible());
+#else
+                    cells_it->vertices.push_back(another);
+#endif
                 }
                 {
                     Point<T> another = vertex;
@@ -1433,7 +1640,11 @@ SimplifiedVoronoi<T, adjust_splines>
                               // y
                               - amount
                               * ( topright(d_it) - bottomright(b_it) ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_2ND_IS_INVISIBLE
                     cells_it->vertices.push_back(another.invisible());
+#else
+                    cells_it->vertices.push_back(another);
+#endif
                 }
                 {
                     Point<T> another = vertex;
@@ -1445,7 +1656,11 @@ SimplifiedVoronoi<T, adjust_splines>
                               - amount
                               * ( topleft(c_it) - bottomleft(a_it) ));
                     another.smooth = true;
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_3RD_IS_INVISIBLE
+                    cells_it->vertices.push_back(another.invisible());
+#else
                     cells_it->vertices.push_back(another);
+#endif
                 }
                 {
                     Point<T> another = vertex;
@@ -1456,9 +1671,15 @@ SimplifiedVoronoi<T, adjust_splines>
                               // y
                               -  amount
                               * ( topleft(c_it) - bottomleft(a_it) ));
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_4TH_IS_INVISIBLE
                     cells_it->vertices.push_back(another.invisible());
+#else
+                    cells_it->vertices.push_back(another);
+#endif
                 }
+#ifdef LIBDEPIXELIZE_ENABLE_EXPERIMENTAL_FEATURES_5TH_IS_INVISIBLE
                 vertex.visible = false;
+#endif
             }
         } else {
             // there is a 4-color pattern, where the current node