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)

1 files changed, 305 insertions, 110 deletions

diff --git a/src/libdepixelize/kopftracer2011.cpp b/src/libdepixelize/kopftracer2011.cpp
index ab31d05c3..e2f387c86 100644
--- a/src/libdepixelize/kopftracer2011.cpp
+++ b/src/libdepixelize/kopftracer2011.cpp
@@ -31,7 +31,6 @@
 #include <glibmm/threads.h>
 #endif
 
-#include <utility>
 #include <algorithm>
 #include "kopftracer2011.h"
 #include "priv/colorspace.h"
@@ -40,6 +39,11 @@
 #include "priv/splines-kopf2011.h"
 #include "priv/iterator.h"
 
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+#include <glibmm/datetime.h>
+#include <iostream>
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
 namespace Tracer {
 namespace Heuristics {
 
@@ -86,7 +90,95 @@ Splines Kopf2011::to_voronoi(const std::string &filename,
 Splines Kopf2011::to_voronoi(const Glib::RefPtr<Gdk::Pixbuf const> &buf,
                              const Options &options)
 {
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    SimplifiedVoronoi<Precision, false> voronoi
+        = _voronoi<Precision, false>(buf, options);
+
+    Glib::DateTime profiling_info[2];
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+
+    Splines ret(voronoi);
+
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::Splines construction time: "
+        << profiling_info[1].difference(profiling_info[0])
+        << std::endl;
+
+    return ret;
+#else // LIBDEPIXELIZE_PROFILE_KOPF2011
     return Splines(_voronoi<Precision, false>(buf, options));
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+}
+
+Splines Kopf2011::to_grouped_voronoi(const std::string &filename,
+                             const Options &options)
+{
+    return to_grouped_voronoi(Gdk::Pixbuf::create_from_file(filename), options);
+}
+
+Splines Kopf2011::to_grouped_voronoi(const Glib::RefPtr<Gdk::Pixbuf const> &buf,
+                             const Options &options)
+{
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    SimplifiedVoronoi<Precision, false> voronoi
+        = _voronoi<Precision, false>(buf, options);
+
+    Glib::DateTime profiling_info[2];
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+
+    HomogeneousSplines<Precision> splines(voronoi);
+
+#else // LIBDEPIXELIZE_PROFILE_KOPF2011
+    HomogeneousSplines<Precision> splines(_voronoi<Precision, false>
+                                          (buf, options));
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::HomogeneousSplines<" << typeid(Precision).name()
+              << ">(Tracer::SimplifiedVoronoi<" << typeid(Precision).name()
+              << ",false>) construction time: "
+              << profiling_info[1].difference(profiling_info[0])
+              << std::endl;
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
+    for ( HomogeneousSplines<Precision>::iterator it = splines.begin(),
+              end = splines.end() ; it != end ; ++it ) {
+        for ( HomogeneousSplines<Precision>::Polygon::points_iter
+                  it2 = it->vertices.begin(), end2 = it->vertices.end()
+                  ; it2 != end2 ; ++it2 ) {
+            it2->smooth = false;
+        }
+        for ( HomogeneousSplines<Precision>::Polygon::holes_iter
+                  it2 = it->holes.begin(), end2 = it->holes.end()
+                  ; it2 != end2 ; ++it2 ) {
+            for ( HomogeneousSplines<Precision>::Polygon::points_iter
+                      it3 = it2->begin(), end3 = it2->end()
+                      ; it3 != end3 ; ++it3 ) {
+                it3->smooth = false;
+            }
+        }
+    }
+
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::Kopf2011::to_grouped_voronoi internal work time: "
+              << profiling_info[1].difference(profiling_info[0])
+              << std::endl;
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+
+    Splines ret(splines, false, options.nthreads);
+
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::Splines construction time: "
+        << profiling_info[1].difference(profiling_info[0])
+        << std::endl;
+
+    return ret;
+#else // LIBDEPIXELIZE_PROFILE_KOPF2011
+    return Splines(splines, false, options.nthreads);
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
 }
 
 Splines Kopf2011::to_splines(const std::string &filename,
@@ -98,9 +190,36 @@ Splines Kopf2011::to_splines(const std::string &filename,
 Splines Kopf2011::to_splines(const Glib::RefPtr<Gdk::Pixbuf const> &buf,
                              const Options &options)
 {
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    SimplifiedVoronoi<Precision, true> voronoi
+        = _voronoi<Precision, true>(buf, options);
+
+    Glib::DateTime profiling_info[2];
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+
+    HomogeneousSplines<Precision> splines(voronoi);
+
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::HomogeneousSplines<" << typeid(Precision).name()
+        << "> construction time: "
+        << profiling_info[1].difference(profiling_info[0])
+        << std::endl;
+
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+
+    Splines ret(splines, options.optimize, options.nthreads);
+
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::Splines construction time: "
+        << profiling_info[1].difference(profiling_info[0])
+        << std::endl;
+
+    return ret;
+#else // LIBDEPIXELIZE_PROFILE_KOPF2011
     HomogeneousSplines<Precision> splines(_voronoi<Precision, true>
                                           (buf, options));
     return Splines(splines, options.optimize, options.nthreads);
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
 }
 
 template<class T, bool adjust_splines>
@@ -108,47 +227,131 @@ SimplifiedVoronoi<T, adjust_splines>
 Kopf2011::_voronoi(const Glib::RefPtr<Gdk::Pixbuf const> &buf,
                    const Options &options)
 {
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    Glib::DateTime profiling_info[2];
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
     PixelGraph graph(buf);
 
-    /*if ( !graph.width() || !graph.height() )
-        return;*/
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::PixelGraph creation time: "
+              << profiling_info[1].difference(profiling_info[0]) << std::endl;
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
+    // gdk-pixbuf2 already checks if image size is meaningful, but asserts state
+    // preconditions and will be useful if gdk-pixbuf is replaced later
+    assert(graph.width() > 0);
+    assert(graph.height() > 0);
 
 #ifndef NDEBUG
     graph.checkConsistency();
 #endif
 
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
     // This step could be part of the initialization of PixelGraph
     // and decrease the necessary number of passes
     graph.connectAllNeighbors();
 
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::PixelGraph::connectAllNeighbors() time: "
+              << profiling_info[1].difference(profiling_info[0]) << std::endl;
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
 #ifndef NDEBUG
     graph.checkConsistency();
 #endif
 
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
     // This step can't be part of PixelGraph initilization without adding some
     // cache misses due to random access patterns that might be injected
     _disconnect_neighbors_with_dissimilar_colors(graph);
 
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::Kopf2011::"
+        "_disconnect_neighbors_with_dissimilar_colors(Tracer::PixelGraph) time: "
+              << profiling_info[1].difference(profiling_info[0]) << std::endl;
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
 #ifndef NDEBUG
     graph.checkConsistency();
 #endif
 
-    // This and below steps must be executed in separate.
-    // Otherwise, there will be colateral effects due to misassumption about the
-    // data being read.
-    _remove_crossing_edges_safe(graph);
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
+    {
+        // edges_safe and edges_unsafe must be executed in separate.
+        // Otherwise, there will be colateral effects due to misassumption about
+        // the data being read.
+        PixelGraph::EdgePairContainer edges = graph.crossingEdges();
+
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::PixelGraph::crossingEdges() time: "
+              << profiling_info[1].difference(profiling_info[0]) << std::endl;
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
+        _remove_crossing_edges_safe(edges);
+
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+        profiling_info[1] = Glib::DateTime::create_now_utc();
+        std::cerr << "Tracer::Kopf2011::_remove_crossing_edges_safe"
+            "(Tracer::PixelGraph) time: "
+                  << profiling_info[1].difference(profiling_info[0])
+                  << std::endl;
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
 
 #ifndef NDEBUG
-    graph.checkConsistency();
+        graph.checkConsistency();
 #endif
 
-    _remove_crossing_edges_unsafe(graph, options);
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+        profiling_info[0] = Glib::DateTime::create_now_utc();
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
+
+        _remove_crossing_edges_unsafe(graph, edges, options);
+    }
+
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::Kopf2011::_remove_crossing_edges_unsafe"
+        "(Tracer::PixelGraph) time: "
+              << profiling_info[1].difference(profiling_info[0]) << std::endl;
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
 
 #ifndef NDEBUG
     graph.checkConsistency();
 #endif
 
+    assert(graph.crossingEdges().size() == 0);
+
+#ifdef LIBDEPIXELIZE_PROFILE_KOPF2011
+    profiling_info[0] = Glib::DateTime::create_now_utc();
+
+    SimplifiedVoronoi<T, adjust_splines> ret(graph);
+
+    profiling_info[1] = Glib::DateTime::create_now_utc();
+    std::cerr << "Tracer::SimplifiedVoronoi<" << typeid(T).name() << ','
+              << (adjust_splines ? "true" : "false")
+              << ">(Tracer::PixelGraph) construction time: "
+              << profiling_info[1].difference(profiling_info[0]) << std::endl;
+
+    return ret;
+#else // LIBDEPIXELIZE_PROFILE_KOPF2011
     return SimplifiedVoronoi<T, adjust_splines>(graph);
+#endif // LIBDEPIXELIZE_PROFILE_KOPF2011
 }
 
 // TODO: move this function (plus connectAllNeighbors) to PixelGraph constructor
@@ -192,123 +395,115 @@ Kopf2011::_disconnect_neighbors_with_dissimilar_colors(PixelGraph &graph)
  *
  * In this case the two diagonal connections can be safely removed without
  * affecting the final result.
- *
- * \TODO: It should remember/cache who are the unsafe crossing edges?
  */
-inline void Kopf2011::_remove_crossing_edges_safe(PixelGraph &graph)
+template<class T>
+void Kopf2011::_remove_crossing_edges_safe(T &container)
 {
-    if ( graph.width() < 2 || graph.height() < 2 )
-        return;
-
-    PixelGraph::iterator it = graph.begin();
-    for ( int i = 0 ; i != graph.height() - 1 ; ++i, ++it ) {
-        for ( int j = 0 ; j != graph.width() - 1 ; ++j, ++it ) {
-            // this <-> right
-            if ( !it->adj.right )
-                continue;
-
-            // this <-> down
-            if ( !it->adj.bottom )
-                continue;
-
-            PixelGraph::iterator down_right = it + graph.width() + 1;
-
-            // down_right <-> right
-            if ( !down_right->adj.top )
-                continue;
+    for ( typename T::reverse_iterator it = container.rbegin(),
+              end = container.rend() ; it != end ; ) {
+        /* A | B
+           --+--
+           C | D */
+        PixelGraph::iterator a = it->first.first;
+        PixelGraph::iterator b = it->second.first;
+        PixelGraph::iterator c = it->second.second;
+        PixelGraph::iterator d = it->first.second;
+
+        if ( !a->adj.right || !a->adj.bottom || !b->adj.bottom
+             || !c->adj.right ) {
+            ++it;
+            continue;
+        }
 
-            // down_right <-> down
-            if ( !down_right->adj.left )
-                continue;
+        // main diagonal
+        a->adj.bottomright = 0;
+        d->adj.topleft = 0;
 
-            // main diagonal
-            // this <-> down_right
-            it->adj.bottomright = 0;
-            down_right->adj.topleft = 0;
+        // secondary diagonal
+        b->adj.bottomleft = 0;
+        c->adj.topright = 0;
 
-            // secondary diagonal
-            // right <-> down
-            (it + 1)->adj.bottomleft = 0;
-            (it + graph.width())->adj.topright = 0;
-        }
+        // base iterator is always past one
+        typename T::iterator current = --(it.base());
+        ++it;
+        container.erase(current);
     }
 }
 
 /**
  * This method removes crossing edges using the heuristics.
  */
-inline
-void Kopf2011::_remove_crossing_edges_unsafe(PixelGraph &graph,
+template<class T>
+void Kopf2011::_remove_crossing_edges_unsafe(PixelGraph &graph, T &edges,
                                              const Options &options)
 {
-    if ( graph.width() < 2 || graph.height() < 2 )
-        return;
-
-    // Iterate over the graph, 2x2 blocks at time
-    PixelGraph::iterator it = graph.begin();
-    for (int i = 0 ; i != graph.height() - 1 ; ++i, ++it ) {
-        for ( int j = 0 ; j != graph.width() - 1 ; ++j, ++it ) {
-            using std::pair;
-            using std::make_pair;
-
-            typedef pair<PixelGraph::iterator, PixelGraph::iterator> Edge;
-            typedef pair<Edge, int> EdgeWeight;
-
-            EdgeWeight diagonals[2] = {
-                make_pair(make_pair(it, graph.nodeBottomRight(it)), 0),
-                make_pair(make_pair(graph.nodeRight(it), graph.nodeBottom(it)),
-                          0)
-            };
-
-            // Check if there are crossing edges
-            if ( !diagonals[0].first.first->adj.bottomright
-                 || !diagonals[1].first.first->adj.bottomleft ) {
-                continue;
-            }
-
-            // Compute weights
-            for ( int i = 0 ; i != 2 ; ++i ) {
-                // Curves and islands heuristics
-                PixelGraph::const_iterator a = diagonals[i].first.first;
-                PixelGraph::const_iterator b = diagonals[i].first.second;
-
-                diagonals[i].second += Heuristics::curves(graph, a, b)
-                    * options.curvesMultiplier;
-
-                diagonals[i].second += Heuristics::islands(a, b)
-                    * options.islandsWeight;
-            }
-
-            {
-                // Sparse pixels heuristic
-                Heuristics::SparsePixels sparse_pixels;
-
-                for ( int i = 0 ; i != 2 ; ++i )
-                    sparse_pixels.diagonals[i] = diagonals[i];
-
-                sparse_pixels(graph, options.sparsePixelsRadius);
-
-                for ( int i = 0 ; i != 2 ; ++i ) {
-                    diagonals[i].second += sparse_pixels.diagonals[i].second
-                        * options.sparsePixelsMultiplier;
-                }
-            }
+    std::vector< std::pair<int, int> > weights(edges.size(),
+                                               std::make_pair(0, 0));
+
+    // Compute weights
+    for ( typename T::size_type i = 0 ; i != edges.size() ; ++i ) {
+        /* A | B
+           --+--
+           C | D */
+        PixelGraph::iterator a = edges[i].first.first;
+        PixelGraph::iterator b = edges[i].second.first;
+        PixelGraph::iterator c = edges[i].second.second;
+        PixelGraph::iterator d = edges[i].first.second;
+
+        // Curves heuristic
+        weights[i].first += Heuristics::curves(graph, a, d)
+            * options.curvesMultiplier;
+        weights[i].second += Heuristics::curves(graph, b, c)
+            * options.curvesMultiplier;
+
+        // Islands heuristic
+        weights[i].first += Heuristics::islands(a, d) * options.islandsWeight;
+        weights[i].second += Heuristics::islands(b, c) * options.islandsWeight;
+
+        // Sparse pixels heuristic
+        using Heuristics::SparsePixels;
+        SparsePixels sparse_pixels;
+
+        sparse_pixels.diagonals[SparsePixels::MAIN_DIAGONAL].first
+            = edges[i].first;
+        sparse_pixels.diagonals[SparsePixels::SECONDARY_DIAGONAL].first
+            = edges[i].second;
+
+        sparse_pixels(graph, options.sparsePixelsRadius);
+
+        weights[i].first
+            += sparse_pixels.diagonals[SparsePixels::MAIN_DIAGONAL].second
+            * options.sparsePixelsMultiplier;
+        weights[i].second
+            += sparse_pixels.diagonals[SparsePixels::SECONDARY_DIAGONAL].second
+            * options.sparsePixelsMultiplier;
+    }
 
-            // Remove edges with lower weight
-            if ( diagonals[0].second > diagonals[1].second ) {
-                diagonals[1].first.first->adj.bottomleft = 0;
-                diagonals[1].first.second->adj.topright = 0;
-            } else if ( diagonals[0].second < diagonals[1].second ) {
-                diagonals[0].first.first->adj.bottomright = 0;
-                diagonals[0].first.second->adj.topleft = 0;
-            } else {
-                diagonals[0].first.first->adj.bottomright = 0;
-                diagonals[0].first.second->adj.topleft = 0;
-                diagonals[1].first.first->adj.bottomleft = 0;
-                diagonals[1].first.second->adj.topright = 0;
-            }
+    // Remove edges with lower weight
+    for ( typename T::size_type i = 0 ; i != edges.size() ; ++i ) {
+        /* A | B
+           --+--
+           C | D */
+        PixelGraph::iterator a = edges[i].first.first;
+        PixelGraph::iterator b = edges[i].second.first;
+        PixelGraph::iterator c = edges[i].second.second;
+        PixelGraph::iterator d = edges[i].first.second;
+
+        if ( weights[i].first > weights[i].second ) {
+            b->adj.bottomleft = 0;
+            c->adj.topright = 0;
+        } else if ( weights[i].first < weights[i].second ) {
+            a->adj.bottomright = 0;
+            d->adj.topleft = 0;
+        } else {
+            a->adj.bottomright = 0;
+            b->adj.bottomleft = 0;
+            c->adj.topright = 0;
+            d->adj.topleft = 0;
         }
     }
+
+    edges.clear();
 }
 
 inline int Heuristics::curves(const PixelGraph &graph,