diff --git a/libs/image/lazybrush/kis_lazy_fill_graph.h b/libs/image/lazybrush/kis_lazy_fill_graph.h
index 205ba920e1..ec30531818 100644
--- a/libs/image/lazybrush/kis_lazy_fill_graph.h
+++ b/libs/image/lazybrush/kis_lazy_fill_graph.h
@@ -1,1028 +1,1030 @@
 /*
  *  Copyright (c) 2016 Dmitry Kazakov <dimula73@gmail.com>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
 #ifndef __KIS_LAZY_FILL_GRAPH_H
 #define __KIS_LAZY_FILL_GRAPH_H
 
 #include <numeric>
 #include <boost/limits.hpp>
 #include <boost/operators.hpp>
 
 #include <boost/graph/graph_traits.hpp>
 #include <boost/graph/properties.hpp>
 #include <boost/iterator/counting_iterator.hpp>
 #include <boost/iterator/transform_iterator.hpp>
 
 #include <QRegion>
 
 //#define USE_LAZY_FILL_SANITY_CHECKS 1
 
 #ifdef USE_LAZY_FILL_SANITY_CHECKS
 #define LF_SANITY_ASSERT(x) KIS_ASSERT(x)
 #define LF_SANITY_ASSERT_RECOVER(x) KIS_ASSERT_RECOVER(x)
 #else
 #define LF_SANITY_ASSERT(x)
 #define LF_SANITY_ASSERT_RECOVER(x) if (0)
 #endif /* USE_LAZY_FILL_SANITY_CHECKS */
 
 
 using namespace boost;
 
 /*
 BOOST_CONCEPT_ASSERT(( ReadablePropertyMapConcept<ScribbleMap, vertex_descriptor> )); //read flow-values from vertices
 */
 
 class KisLazyFillGraph;
 
 //===================
 // Index Property Map
 //===================
 
 template <typename Graph,
           typename Descriptor,
           typename Index>
 struct lazy_fill_graph_index_map {
 public:
     typedef Index value_type;
     typedef Index reference_type;
     typedef reference_type reference;
     typedef Descriptor key_type;
     typedef readable_property_map_tag category;
 
     lazy_fill_graph_index_map() { }
 
     lazy_fill_graph_index_map(const Graph& graph) :
         m_graph(&graph) { }
 
     value_type operator[](key_type key) const {
         value_type index = m_graph->index_of(key);
         LF_SANITY_ASSERT(index >= 0);
         return index;
     }
 
     friend inline Index
     get(const lazy_fill_graph_index_map<Graph, Descriptor, Index>& index_map,
         const typename lazy_fill_graph_index_map<Graph, Descriptor, Index>::key_type& key)
         {
             return (index_map[key]);
         }
 
 protected:
     const Graph* m_graph;
 };
 
 //==========================
 // Reverse Edge Property Map
 //==========================
 
 template <typename Descriptor>
 struct lazy_fill_graph_reverse_edge_map {
 public:
     typedef Descriptor value_type;
     typedef Descriptor reference_type;
     typedef reference_type reference;
     typedef Descriptor key_type;
     typedef readable_property_map_tag category;
 
     lazy_fill_graph_reverse_edge_map() { }
 
     value_type operator[](const key_type& key) const {
         return (value_type(key.second, key.first));
     }
 
     friend inline Descriptor
     get(const lazy_fill_graph_reverse_edge_map<Descriptor>& rev_map,
         const typename lazy_fill_graph_reverse_edge_map<Descriptor>::key_type& key)
         {
             return (rev_map[key]);
         }
 };
 
 //=================
 // Function Objects
 //=================
 
 namespace kis_detail {
 
     // vertex_at
     template <typename Graph>
     struct lazy_fill_graph_vertex_at {
 
         typedef typename graph_traits<Graph>::vertex_descriptor result_type;
 
         lazy_fill_graph_vertex_at() : m_graph(0) {}
 
         lazy_fill_graph_vertex_at(const Graph* graph) :
             m_graph(graph) { }
 
         result_type
         operator()
         (typename graph_traits<Graph>::vertices_size_type vertex_index) const {
             return (vertex(vertex_index, *m_graph));
         }
 
     private:
         const Graph* m_graph;
     };
 
     // out_edge_at
     template <typename Graph>
     struct lazy_fill_graph_out_edge_at {
 
     private:
         typedef typename graph_traits<Graph>::vertex_descriptor vertex_descriptor;
 
     public:
         typedef typename graph_traits<Graph>::edge_descriptor result_type;
 
         lazy_fill_graph_out_edge_at() : m_vertex(), m_graph(0) {}
 
         lazy_fill_graph_out_edge_at(vertex_descriptor source_vertex,
                                const Graph* graph) :
             m_vertex(source_vertex),
             m_graph(graph) { }
 
         result_type
         operator()
         (typename graph_traits<Graph>::degree_size_type out_edge_index) const {
             return (out_edge_at(m_vertex, out_edge_index, *m_graph));
         }
 
     private:
         vertex_descriptor m_vertex;
         const Graph* m_graph;
     };
 
     // in_edge_at
     template <typename Graph>
     struct lazy_fill_graph_in_edge_at {
 
     private:
         typedef typename graph_traits<Graph>::vertex_descriptor vertex_descriptor;
 
     public:
         typedef typename graph_traits<Graph>::edge_descriptor result_type;
 
         lazy_fill_graph_in_edge_at() : m_vertex(), m_graph(0) {}
 
         lazy_fill_graph_in_edge_at(vertex_descriptor target_vertex,
                               const Graph* graph) :
             m_vertex(target_vertex),
             m_graph(graph) { }
 
         result_type
         operator()
         (typename graph_traits<Graph>::degree_size_type in_edge_index) const {
             return (in_edge_at(m_vertex, in_edge_index, *m_graph));
         }
 
     private:
         vertex_descriptor m_vertex;
         const Graph* m_graph;
     };
 
     // edge_at
     template <typename Graph>
     struct lazy_fill_graph_edge_at {
 
         typedef typename graph_traits<Graph>::edge_descriptor result_type;
 
         lazy_fill_graph_edge_at() : m_graph(0) {}
 
         lazy_fill_graph_edge_at(const Graph* graph) :
             m_graph(graph) { }
 
         result_type
         operator()
         (typename graph_traits<Graph>::edges_size_type edge_index) const {
             return (edge_at(edge_index, *m_graph));
         }
 
     private:
         const Graph* m_graph;
     };
 
     // adjacent_vertex_at
     template <typename Graph>
     struct lazy_fill_graph_adjacent_vertex_at {
 
     public:
         typedef typename graph_traits<Graph>::vertex_descriptor result_type;
 
         lazy_fill_graph_adjacent_vertex_at(result_type source_vertex,
                                       const Graph* graph) :
             m_vertex(source_vertex),
             m_graph(graph) { }
 
         result_type
         operator()
         (typename graph_traits<Graph>::degree_size_type adjacent_index) const {
             return (target(out_edge_at(m_vertex, adjacent_index, *m_graph), *m_graph));
         }
 
     private:
         result_type m_vertex;
         const Graph* m_graph;
     };
 
 } // namespace kis_detail
 
 
 class KisLazyFillGraph
 {
 public:
     typedef KisLazyFillGraph type;
 
 
     typedef long VertexIndex;
     typedef long EdgeIndex;
 
     // sizes
     typedef VertexIndex vertices_size_type;
     typedef EdgeIndex edges_size_type;
     typedef EdgeIndex degree_size_type;
 
     struct VertexDescriptor : public equality_comparable<VertexDescriptor>
     {
         enum VertexType {
             NORMAL = 0,
             LABEL_A,
             LABEL_B
         };
 
         vertices_size_type x;
         vertices_size_type y;
         VertexType type;
 
         VertexDescriptor(vertices_size_type _x, vertices_size_type _y, VertexType _type = NORMAL)
             : x(_x), y(_y), type(_type) {}
 
         // TODO: Extra constructors look unnecessary, ask Dmitry before removing
         VertexDescriptor(VertexType _type)
             : x(0), y(0), type(_type) {}
 
         VertexDescriptor()
             : x(0), y(0), type(NORMAL) {}
 
         bool operator ==(const VertexDescriptor &rhs) const {
             return rhs.x == x && rhs.y == y && rhs.type == type;
         }
     };
 
     // descriptors
     typedef VertexDescriptor vertex_descriptor;
     typedef std::pair<vertex_descriptor, vertex_descriptor> edge_descriptor;
 
     friend QDebug operator<<(QDebug dbg, const KisLazyFillGraph::edge_descriptor &e);
     friend QDebug operator<<(QDebug dbg, const KisLazyFillGraph::vertex_descriptor &v);
 
     // vertex_iterator
     typedef counting_iterator<vertices_size_type> vertex_index_iterator;
     typedef kis_detail::lazy_fill_graph_vertex_at<KisLazyFillGraph> vertex_function;
     typedef transform_iterator<vertex_function, vertex_index_iterator> vertex_iterator;
 
     // edge_iterator
     typedef counting_iterator<edges_size_type> edge_index_iterator;
     typedef kis_detail::lazy_fill_graph_edge_at<type> edge_function;
     typedef transform_iterator<edge_function, edge_index_iterator> edge_iterator;
 
     // out_edge_iterator
     typedef counting_iterator<degree_size_type> degree_iterator;
     typedef kis_detail::lazy_fill_graph_out_edge_at<type> out_edge_function;
     typedef transform_iterator<out_edge_function, degree_iterator> out_edge_iterator;
 
     // adjacency_iterator
     typedef kis_detail::lazy_fill_graph_adjacent_vertex_at<type> adjacent_vertex_function;
     typedef transform_iterator<adjacent_vertex_function, degree_iterator> adjacency_iterator;
 
     // categories
     typedef directed_tag directed_category;
     typedef disallow_parallel_edge_tag edge_parallel_category;
     struct traversal_category : virtual public incidence_graph_tag,
                                 virtual public adjacency_graph_tag,
                                 virtual public vertex_list_graph_tag,
                                 virtual public edge_list_graph_tag,
                                 virtual public adjacency_matrix_tag { };
 
     static inline vertex_descriptor null_vertex()
     {
         vertex_descriptor maxed_out_vertex(
             std::numeric_limits<vertices_size_type>::max(),
             std::numeric_limits<vertices_size_type>::max(),
             vertex_descriptor::NORMAL);
 
         return (maxed_out_vertex);
     }
 
     KisLazyFillGraph() {}
 
     KisLazyFillGraph(const QRect &mainRect,
                      const QRegion &aLabelRegion,
                      const QRegion &bLabelRegion)
         : m_x(mainRect.x()),
           m_y(mainRect.y()),
           m_width(mainRect.width()),
           m_height(mainRect.height())
     {
         m_mainArea = mainRect;
         m_aLabelArea = aLabelRegion.boundingRect();
         m_bLabelArea = bLabelRegion.boundingRect();
+
+        //QRegion::rects() is deprecated, https://doc.qt.io/qt-5/qregion-obsolete.html#rects
         m_aLabelRects = aLabelRegion.rects();
         m_bLabelRects = bLabelRegion.rects();
 
         KIS_ASSERT(m_mainArea.contains(m_aLabelArea));
         KIS_ASSERT(m_mainArea.contains(m_bLabelArea));
 
         m_numVertices = m_width * m_height + 2;
 
         m_edgeBins << EdgeIndexBin(0,                 m_mainArea.adjusted(0, 0, -1, 0), HORIZONTAL);
         m_edgeBins << EdgeIndexBin(m_edgeBins.last(), m_mainArea.adjusted(0, 0, -1, 0), HORIZONTAL_REVERSED);
 
         m_edgeBins << EdgeIndexBin(m_edgeBins.last(), m_mainArea.adjusted(0, 0, 0, -1), VERTICAL);
         m_edgeBins << EdgeIndexBin(m_edgeBins.last(), m_mainArea.adjusted(0, 0, 0, -1), VERTICAL_REVERSED);
 
         Q_FOREACH (const QRect &rc, m_aLabelRects) {
             m_edgeBins << EdgeIndexBin(m_edgeBins.last(), rc, LABEL_A);
         }
 
         // out_edge_at relies on the sequential layout of reversed edges of one type
         m_aReversedEdgesStart = m_edgeBins.last().last() + 1;
 
         Q_FOREACH (const QRect &rc, m_aLabelRects) {
             m_edgeBins << EdgeIndexBin(m_edgeBins.last(), rc, LABEL_A_REVERSED);
         }
 
         m_numAEdges = m_edgeBins.last().last() + 1 - m_aReversedEdgesStart;
 
         Q_FOREACH (const QRect &rc, m_bLabelRects) {
             m_edgeBins << EdgeIndexBin(m_edgeBins.last(), rc, LABEL_B);
         }
 
         // out_edge_at relies on the sequential layout of reversed edges of one type
         m_bReversedEdgesStart = m_edgeBins.last().last() + 1;
 
         Q_FOREACH (const QRect &rc, m_bLabelRects) {
             m_edgeBins << EdgeIndexBin(m_edgeBins.last(), rc, LABEL_B_REVERSED);
         }
 
         m_numBEdges = m_edgeBins.last().last() + 1 - m_bReversedEdgesStart;
 
         m_numEdges = m_edgeBins.last().last() + 1;
     }
 
     ~KisLazyFillGraph() {
 
     }
 
     QSize size() const { return QSize(m_width, m_height); }
     QRect rect() const { return QRect(m_x, m_y, m_width, m_height); }
 
 
     vertices_size_type m_x;
     vertices_size_type m_y;
 
     vertices_size_type m_width;
     vertices_size_type m_height;
 
     vertices_size_type m_numVertices;
     vertices_size_type m_numEdges;
 
     vertices_size_type m_aReversedEdgesStart;
     vertices_size_type m_bReversedEdgesStart;
     vertices_size_type m_numAEdges;
     vertices_size_type m_numBEdges;
 
     enum EdgeIndexBinId {
         HORIZONTAL,
         HORIZONTAL_REVERSED,
         VERTICAL,
         VERTICAL_REVERSED,
         LABEL_A,
         LABEL_A_REVERSED,
         LABEL_B,
         LABEL_B_REVERSED,
     };
 
     struct EdgeIndexBin {
         EdgeIndexBin()
             : start(0), stride(0), size(0) {}
 
         EdgeIndexBin(edges_size_type _start,
                      const QRect &_rect,
                      EdgeIndexBinId _binId)
             : start(_start),
               stride(_rect.width()),
               size(_rect.width() * _rect.height()),
               xOffset(_rect.x()),
               yOffset(_rect.y()),
               binId(_binId),
               isReversed(int(_binId) & 0x1),
               rect(_rect) {}
 
         EdgeIndexBin(const EdgeIndexBin &putAfter,
                      const QRect &_rect,
                      EdgeIndexBinId _binId)
             : start(putAfter.last() + 1),
               stride(_rect.width()),
               size(_rect.width() * _rect.height()),
               xOffset(_rect.x()),
               yOffset(_rect.y()),
               binId(_binId),
               isReversed(int(_binId) & 0x1),
               rect(_rect) {}
 
         edges_size_type last() const {
             return start + size - 1;
         }
 
         bool contains(edges_size_type index) const {
             index -= start;
             return index >= 0 && index < size;
         }
 
         bool contains(const edge_descriptor &edge) const {
             return indexOf(edge) >= 0;
         }
 
         edges_size_type indexOf(const edge_descriptor &edge) const {
             vertex_descriptor src_vertex = source(edge, *this);
             vertex_descriptor dst_vertex = target(edge, *this);
 
             const bool srcColoredA = src_vertex.type == vertex_descriptor::LABEL_A;
             const bool dstColoredA = dst_vertex.type == vertex_descriptor::LABEL_A;
             const bool srcColoredB = src_vertex.type == vertex_descriptor::LABEL_B;
             const bool dstColoredB = dst_vertex.type == vertex_descriptor::LABEL_B;
 
             if (srcColoredA || dstColoredA) {
                 const bool edgeReversed = srcColoredA;
 
                 if (isReversed != edgeReversed ||
                     (binId != LABEL_A && binId != LABEL_A_REVERSED) ||
                     (srcColoredA && (dst_vertex.type != vertex_descriptor::NORMAL)) ||
                     (dstColoredA && (src_vertex.type != vertex_descriptor::NORMAL))) {
 
                     return -1;
                 }
             } else if (srcColoredB || dstColoredB) {
                 const bool edgeReversed = srcColoredB;
 
                 if (isReversed != edgeReversed ||
                     (binId != LABEL_B && binId != LABEL_B_REVERSED) ||
                     (srcColoredB && (dst_vertex.type != vertex_descriptor::NORMAL)) ||
                     (dstColoredB && (src_vertex.type != vertex_descriptor::NORMAL))) {
 
                     return -1;
                 }
             } else {
                 const vertices_size_type xDiff = dst_vertex.x - src_vertex.x;
                 const vertices_size_type yDiff = dst_vertex.y - src_vertex.y;
                 const vertices_size_type xAbsDiff = qAbs(xDiff);
                 const vertices_size_type yAbsDiff = qAbs(yDiff);
                 const bool edgeReversed = xDiff < 0 || yDiff < 0;
 
                 if (isReversed != edgeReversed ||
                     (xDiff && binId != HORIZONTAL && binId != HORIZONTAL_REVERSED) ||
                     (yDiff && binId != VERTICAL && binId != VERTICAL_REVERSED) ||
                     xAbsDiff > 1 ||
                     yAbsDiff > 1 ||
                     xAbsDiff == yAbsDiff) {
 
                     return -1;
                 }
             }
 
             if (isReversed) {
                 std::swap(src_vertex, dst_vertex);
             }
 
             // using direct QRect::contains makes the code 30% slower
             const int x = src_vertex.x;
             const int y = src_vertex.y;
             if (x < rect.x() || x > rect.right() ||
                 y < rect.y() || y > rect.bottom()) {
                 return -1;
             }
 
             edges_size_type internalIndex =
                 (src_vertex.x - xOffset) +
                 (src_vertex.y - yOffset) * stride;
 
             LF_SANITY_ASSERT_RECOVER(internalIndex >= 0 && internalIndex < size) {
                 return -1;
             }
 
             return internalIndex + start;
         }
 
 
         edge_descriptor edgeAt(edges_size_type index) const {
             edges_size_type localOffset = index - start;
 
             if (localOffset < 0 || localOffset >= size) {
                 return edge_descriptor();
             }
 
             const edges_size_type x = localOffset % stride + xOffset;
             const edges_size_type y = localOffset / stride + yOffset;
 
             vertex_descriptor src_vertex(x, y, vertex_descriptor::NORMAL);
             vertex_descriptor dst_vertex;
 
             switch (binId) {
             case HORIZONTAL:
             case HORIZONTAL_REVERSED:
                 dst_vertex.x = x + 1;
                 dst_vertex.y = y;
                 dst_vertex.type = vertex_descriptor::NORMAL;
                 break;
             case VERTICAL:
             case VERTICAL_REVERSED:
                 dst_vertex.x = x;
                 dst_vertex.y = y + 1;
                 dst_vertex.type = vertex_descriptor::NORMAL;
                 break;
             case LABEL_A:
             case LABEL_A_REVERSED:
                 dst_vertex.type = vertex_descriptor::LABEL_A;
                 break;
             case LABEL_B:
             case LABEL_B_REVERSED:
                 dst_vertex.type = vertex_descriptor::LABEL_B;
                 break;
             }
 
             if (isReversed) {
                 std::swap(src_vertex, dst_vertex);
             }
 
             return std::make_pair(src_vertex, dst_vertex);
         }
 
         edges_size_type start;
         edges_size_type stride;
         edges_size_type size;
         edges_size_type xOffset;
         edges_size_type yOffset;
         EdgeIndexBinId binId;
         bool isReversed;
         QRect rect;
     };
 
     QVector<EdgeIndexBin> m_edgeBins;
 
     QRect m_aLabelArea;
     QRect m_bLabelArea;
     QRect m_mainArea;
 
     QVector<QRect> m_aLabelRects;
     QVector<QRect> m_bLabelRects;
 
 public:
 
     // Returns the number of vertices in the graph
     inline vertices_size_type num_vertices() const {
       return (m_numVertices);
     }
 
     // Returns the number of edges in the graph
     inline edges_size_type num_edges() const {
       return (m_numEdges);
     }
 
     // Returns the index of [vertex] (See also vertex_at)
     vertices_size_type index_of(vertex_descriptor vertex) const {
         vertices_size_type vertex_index = -1;
 
         switch (vertex.type) {
         case vertex_descriptor::NORMAL:
             vertex_index = vertex.x - m_x + (vertex.y - m_y) * m_width;
             break;
         case vertex_descriptor::LABEL_A:
             vertex_index = m_numVertices - 2;
             break;
         case vertex_descriptor::LABEL_B:
             vertex_index = m_numVertices - 1;
             break;
         }
 
         return vertex_index;
     }
 
     // Returns the vertex whose index is [vertex_index] (See also
     // index_of(vertex_descriptor))
     vertex_descriptor vertex_at (vertices_size_type vertex_index) const {
         vertex_descriptor vertex;
 
         if (vertex_index == m_numVertices - 2) {
             vertex.type = vertex_descriptor::LABEL_A;
         } else if (vertex_index == m_numVertices - 1) {
             vertex.type = vertex_descriptor::LABEL_B;
         } else if (vertex_index >= 0) {
             vertex.x = vertex_index % m_width + m_x;
             vertex.y = vertex_index / m_width + m_y;
             vertex.type = vertex_descriptor::NORMAL;
         }
 
       return vertex;
     }
 
     // Returns the edge whose index is [edge_index] (See also
     // index_of(edge_descriptor)).  NOTE: The index mapping is
     // dependent upon dimension wrapping.
     edge_descriptor edge_at(edges_size_type edge_index) const {
 
         int binIndex = 0;
 
         while (binIndex < m_edgeBins.size() &&
                !m_edgeBins[binIndex].contains(edge_index)) {
 
             binIndex++;
         }
 
         if (binIndex >= m_edgeBins.size()) {
             return edge_descriptor();
         }
 
         return m_edgeBins[binIndex].edgeAt(edge_index);
     }
 
     // Returns the index for [edge] (See also edge_at)
     edges_size_type index_of(edge_descriptor edge) const {
         edges_size_type index = -1;
 
         auto it = m_edgeBins.constBegin();
         for (; it != m_edgeBins.constEnd(); ++it) {
 
             index = it->indexOf(edge);
             if (index >= 0) break;
         }
 
         return index;
     }
 
 private:
     static vertices_size_type numVacantEdges(const vertex_descriptor &vertex, const QRect &rc) {
         vertices_size_type vacantEdges = 4;
 
         if (vertex.x == rc.x()) {
             vacantEdges--;
         }
 
         if (vertex.y == rc.y()) {
             vacantEdges--;
         }
 
         if (vertex.x == rc.right()) {
             vacantEdges--;
         }
 
         if (vertex.y == rc.bottom()) {
             vacantEdges--;
         }
 
         return vacantEdges;
     }
 
     static inline bool findInRects(const QVector<QRect> &rects, const QPoint &pt) {
         bool result = false;
 
         auto it = rects.constBegin();
         for (; it != rects.constEnd(); ++it) {
 
             if (it->contains(pt)) {
                 result = true;
                 break;
             }
         }
         return result;
     }
 public:
     // Returns the number of out-edges for [vertex]
     degree_size_type out_degree(vertex_descriptor vertex) const {
         degree_size_type out_edge_count = 0;
         if (index_of(vertex) < 0) return out_edge_count;
 
         switch (vertex.type) {
         case vertex_descriptor::NORMAL: {
             out_edge_count = numVacantEdges(vertex, m_mainArea);
 
             const QPoint pt = QPoint(vertex.x, vertex.y);
 
             if (m_aLabelArea.contains(pt) && findInRects(m_aLabelRects, pt)) {
                 out_edge_count++;
             }
 
             if (m_bLabelArea.contains(pt) && findInRects(m_bLabelRects, pt)) {
                 out_edge_count++;
             }
 
             break;
         }
         case vertex_descriptor::LABEL_A:
             out_edge_count = m_numAEdges;
             break;
         case vertex_descriptor::LABEL_B:
             out_edge_count = m_numBEdges;
             break;
         }
 
         return (out_edge_count);
     }
 
     // Returns an out-edge for [vertex] by index. Indices are in the
     // range [0, out_degree(vertex)).
     edge_descriptor out_edge_at (vertex_descriptor vertex,
                                  degree_size_type out_edge_index) const {
 
         const QPoint pt = QPoint(vertex.x, vertex.y);
         vertex_descriptor dst_vertex = vertex;
 
         switch (vertex.type) {
         case vertex_descriptor::NORMAL:
             if (vertex.x > m_mainArea.x() && !out_edge_index--) {
                 dst_vertex.x--;
             } else if (vertex.y > m_mainArea.y() && !out_edge_index--) {
                 dst_vertex.y--;
             } else if (vertex.x < m_mainArea.right() && !out_edge_index--) {
                 dst_vertex.x++;
             } else if (vertex.y < m_mainArea.bottom() && !out_edge_index--) {
                 dst_vertex.y++;
             } else if (m_aLabelArea.contains(pt) && findInRects(m_aLabelRects, pt) && !out_edge_index--) {
                 dst_vertex = vertex_descriptor(0, 0, vertex_descriptor::LABEL_A);
             } else if (m_bLabelArea.contains(pt) && findInRects(m_bLabelRects, pt) && !out_edge_index--) {
                 dst_vertex = vertex_descriptor(0, 0, vertex_descriptor::LABEL_B);
             } else {
                 dbgImage << ppVar(vertex) << ppVar(out_edge_index) << ppVar(out_degree(vertex));
                 qFatal("Wrong edge sub-index");
             }
             break;
         case vertex_descriptor::LABEL_A: {
             edge_descriptor edge = edge_at(m_aReversedEdgesStart + out_edge_index);
             dst_vertex = edge.second;
             break;
         }
         case vertex_descriptor::LABEL_B: {
             edge_descriptor edge = edge_at(m_bReversedEdgesStart + out_edge_index);
             dst_vertex = edge.second;
             break;
         }
         }
 
         return std::make_pair(vertex, dst_vertex);
     }
 
 public:
 
     //================
     // VertexListGraph
     //================
 
     friend inline std::pair<typename type::vertex_iterator,
                             typename type::vertex_iterator>
     vertices(const type& graph) {
         typedef typename type::vertex_iterator vertex_iterator;
         typedef typename type::vertex_function vertex_function;
         typedef typename type::vertex_index_iterator vertex_index_iterator;
 
         return (std::make_pair
                 (vertex_iterator(vertex_index_iterator(0),
                                  vertex_function(&graph)),
                  vertex_iterator(vertex_index_iterator(graph.num_vertices()),
                                  vertex_function(&graph))));
     }
 
     friend inline typename type::vertices_size_type
     num_vertices(const type& graph) {
         return (graph.num_vertices());
     }
 
     friend inline typename type::vertex_descriptor
     vertex(typename type::vertices_size_type vertex_index,
            const type& graph) {
 
         return (graph.vertex_at(vertex_index));
     }
 
     //===============
     // IncidenceGraph
     //===============
 
     friend inline std::pair<typename type::out_edge_iterator,
                             typename type::out_edge_iterator>
     out_edges(typename type::vertex_descriptor vertex,
               const type& graph) {
         typedef typename type::degree_iterator degree_iterator;
         typedef typename type::out_edge_function out_edge_function;
         typedef typename type::out_edge_iterator out_edge_iterator;
 
         return (std::make_pair
                 (out_edge_iterator(degree_iterator(0),
                                    out_edge_function(vertex, &graph)),
                  out_edge_iterator(degree_iterator(graph.out_degree(vertex)),
                                    out_edge_function(vertex, &graph))));
     }
 
     friend inline typename type::degree_size_type
     out_degree
     (typename type::vertex_descriptor vertex,
      const type& graph) {
         return (graph.out_degree(vertex));
     }
 
     friend inline typename type::edge_descriptor
     out_edge_at(typename type::vertex_descriptor vertex,
                 typename type::degree_size_type out_edge_index,
                 const type& graph) {
         return (graph.out_edge_at(vertex, out_edge_index));
     }
 
     //===============
     // AdjacencyGraph
     //===============
 
     friend typename std::pair<typename type::adjacency_iterator,
                               typename type::adjacency_iterator>
     adjacent_vertices (typename type::vertex_descriptor vertex,
                        const type& graph) {
       typedef typename type::degree_iterator degree_iterator;
       typedef typename type::adjacent_vertex_function adjacent_vertex_function;
       typedef typename type::adjacency_iterator adjacency_iterator;
 
       return (std::make_pair
               (adjacency_iterator(degree_iterator(0),
                                  adjacent_vertex_function(vertex, &graph)),
                adjacency_iterator(degree_iterator(graph.out_degree(vertex)),
                                  adjacent_vertex_function(vertex, &graph))));
     }
 
     //==================
     // Adjacency Matrix
     //==================
 
     friend std::pair<typename type::edge_descriptor, bool>
     edge (typename type::vertex_descriptor source_vertex,
           typename type::vertex_descriptor destination_vertex,
           const type& graph) {
 
         std::pair<typename type::edge_descriptor, bool> edge_exists =
             std::make_pair(std::make_pair(source_vertex, destination_vertex), false);
 
         const edges_size_type index = graph.index_of(edge_exists.first);
 
         edge_exists.second = index >= 0;
 
         return edge_exists;
     }
 
     //==============
     // EdgeListGraph
     //==============
 
     friend inline typename type::edges_size_type
     num_edges(const type& graph) {
       return (graph.num_edges());
     }
 
     friend inline typename type::edge_descriptor
     edge_at(typename type::edges_size_type edge_index,
             const type& graph) {
       return (graph.edge_at(edge_index));
     }
 
     friend inline std::pair<typename type::edge_iterator,
                             typename type::edge_iterator>
     edges(const type& graph) {
       typedef typename type::edge_index_iterator edge_index_iterator;
       typedef typename type::edge_function edge_function;
       typedef typename type::edge_iterator edge_iterator;
 
       return (std::make_pair
               (edge_iterator(edge_index_iterator(0),
                              edge_function(&graph)),
                edge_iterator(edge_index_iterator(graph.num_edges()),
                              edge_function(&graph))));
     }
 
     //=============================
     // Index Property Map Functions
     //=============================
 
     friend inline typename type::vertices_size_type
     get(vertex_index_t,
         const type& graph,
         typename type::vertex_descriptor vertex) {
 
         type::vertices_size_type index = graph.index_of(vertex);
         LF_SANITY_ASSERT(index >= 0);
         return index;
     }
 
     friend inline typename type::edges_size_type
     get(edge_index_t,
         const type& graph,
         typename type::edge_descriptor edge) {
 
         type::edges_size_type index = graph.index_of(edge);
         LF_SANITY_ASSERT(index >= 0);
         return index;
     }
 
     friend inline lazy_fill_graph_index_map<
         type,
         typename type::vertex_descriptor,
         typename type::vertices_size_type>
     get(vertex_index_t, const type& graph) {
         return (lazy_fill_graph_index_map<
                 type,
                 typename type::vertex_descriptor,
                 typename type::vertices_size_type>(graph));
     }
 
     friend inline lazy_fill_graph_index_map<
         type,
         typename type::edge_descriptor,
         typename type::edges_size_type>
     get(edge_index_t, const type& graph) {
         return (lazy_fill_graph_index_map<
                 type,
                 typename type::edge_descriptor,
                 typename type::edges_size_type>(graph));
     }
 
     friend inline lazy_fill_graph_reverse_edge_map<
         typename type::edge_descriptor>
     get(edge_reverse_t, const type& graph) {
         Q_UNUSED(graph);
         return (lazy_fill_graph_reverse_edge_map<
                 typename type::edge_descriptor>());
     }
 
     template<typename Graph,
              typename Descriptor,
              typename Index>
     friend struct lazy_fill_graph_index_map;
 
     template<typename Descriptor>
     friend struct lazy_fill_graph_reverse_edge_map;
 };
 
 namespace boost {
     template <>
     struct property_map<KisLazyFillGraph, vertex_index_t> {
         typedef lazy_fill_graph_index_map<KisLazyFillGraph,
                                           typename graph_traits<KisLazyFillGraph>::vertex_descriptor,
                                           typename graph_traits<KisLazyFillGraph>::vertices_size_type> type;
         typedef type const_type;
     };
 
     template<>
     struct property_map<KisLazyFillGraph, edge_index_t> {
         typedef lazy_fill_graph_index_map<KisLazyFillGraph,
                                           typename graph_traits<KisLazyFillGraph>::edge_descriptor,
                                           typename graph_traits<KisLazyFillGraph>::edges_size_type> type;
         typedef type const_type;
     };
 }
 
 namespace boost {
     template <>
     struct property_map<KisLazyFillGraph, edge_reverse_t> {
         typedef lazy_fill_graph_reverse_edge_map<typename graph_traits<KisLazyFillGraph>::edge_descriptor> type;
         typedef type const_type;
     };
 }
 
 QDebug operator<<(QDebug dbg, const KisLazyFillGraph::vertex_descriptor &v) {
     const QString type =
         v.type == KisLazyFillGraph::vertex_descriptor::NORMAL ? "normal" :
         v.type == KisLazyFillGraph::vertex_descriptor::LABEL_A ? "label_A" :
         v.type == KisLazyFillGraph::vertex_descriptor::LABEL_B ? "label_B" : "<unknown>";
 
     dbg.nospace() << "(" << v.x << ", " << v.y << ", " << type << ")";
     return dbg.space();
 }
 
 QDebug operator<<(QDebug dbg, const KisLazyFillGraph::edge_descriptor &e) {
     KisLazyFillGraph::vertex_descriptor src = e.first;
     KisLazyFillGraph::vertex_descriptor dst = e.second;
 
     dbg.nospace() << "(" << src << " -> " << dst << ")";
     return dbg.space();
 }
 
 #endif /* __KIS_LAZY_FILL_GRAPH_H */
diff --git a/plugins/tools/selectiontools/KisMagneticWorker.cc b/plugins/tools/selectiontools/KisMagneticWorker.cc
index 1a3e2a5c3a..9f98cf06dc 100644
--- a/plugins/tools/selectiontools/KisMagneticWorker.cc
+++ b/plugins/tools/selectiontools/KisMagneticWorker.cc
@@ -1,75 +1,83 @@
 /*
  *  Copyright (c) 2019 Kuntal Majumder <hellozee@disroot.org>
  *
  *  This library is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU Lesser General Public License as published by
  *  the Free Software Foundation; version 2.1 of the License.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU Lesser General Public License for more details.
  *
  *  You should have received a copy of the GNU Lesser General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
 #include "KisMagneticWorker.h"
 
 #include "kis_gaussian_kernel.h"
 
 #include <QtCore>
 #include <boost/graph/astar_search.hpp>
 #include <boost/functional/hash.hpp>
 #include <boost/unordered_map.hpp>
 #include <libs/image/lazybrush/kis_lazy_fill_graph.h>
 
 typedef KisLazyFillGraph::VertexDescriptor VertexDescriptor;
 
 struct VertexHash : std::unary_function<VertexDescriptor, std::size_t> {
   std::size_t operator()(VertexDescriptor const& u) const {
     std::size_t seed = 0;
     boost::hash_combine(seed, u.x);
     boost::hash_combine(seed, u.y);
     return seed;
   }
 };
 
 typedef boost::unordered_map<VertexDescriptor, VertexDescriptor, VertexHash> PredMap;
 typedef boost::associative_property_map<PredMap> APredMap;
 
 class AstarHeuristic : public boost::astar_heuristic<KisLazyFillGraph, double> {
     private:
         APredMap m_pmap;
         VertexDescriptor m_goal;
         double coeff_a, coeff_b;
 
     public:
         AstarHeuristic(VertexDescriptor goal, APredMap pmap, double a, double b):
             m_pmap(pmap), m_goal(goal), coeff_a(a), coeff_b(b)
         { }
 
         AstarHeuristic(VertexDescriptor goal, APredMap pmap):
             m_pmap(pmap), m_goal(goal), coeff_a(0.5), coeff_b(0.5)
         { }
 
         double operator()(VertexDescriptor v){
             auto prev = m_pmap[v];
-            auto di = (m_goal.y - prev.y) * v.x + (m_goal.x - prev.x) * v.y;
+            double di = (m_goal.y - prev.y) * v.x + (m_goal.x - prev.x) * v.y;
             di = std::abs(di + prev.x * m_goal.y + prev.y * m_goal.x);
             auto dist = [](VertexDescriptor p1, VertexDescriptor p2){
                 return std::sqrt(std::pow(p1.y-p2.y, 2) + std::pow(p1.x-p2.x, 2));
             };
-            auto dz = dist(prev, m_goal);
+            double dz = dist(prev, m_goal);
             di = di/dz;
-            auto dm = dist(v, m_goal);
+            double dm = dist(v, m_goal);
             return coeff_a * di + coeff_b * (dm - dz);
         }
 };
 
+KisMagneticWorker::KisMagneticWorker(KisPaintDeviceSP dev, const QRect &rect):
+    m_dev(dev), m_rect(rect)
+{ }
+
 void KisMagneticWorker::run(KisPaintDeviceSP dev, const QRect &rect)
 {
     KisGaussianKernel::applyLoG(dev, rect, 2, -1.0, QBitArray(), 0);
 }
 
+void KisMagneticWorker::computeEdge(QPoint start, QPoint end)
+{
+    KisGaussianKernel::applyLoG(m_dev, m_rect, 2, -1.0, QBitArray(), 0);
+}
diff --git a/plugins/tools/selectiontools/KisMagneticWorker.h b/plugins/tools/selectiontools/KisMagneticWorker.h
index 9c10a5a668..24a5a8d72e 100644
--- a/plugins/tools/selectiontools/KisMagneticWorker.h
+++ b/plugins/tools/selectiontools/KisMagneticWorker.h
@@ -1,29 +1,35 @@
 /*
  *  Copyright (c) 2019 Kuntal Majumder <hellozee@disroot.org>
  *
  *  This library is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU Lesser General Public License as published by
  *  the Free Software Foundation; version 2.1 of the License.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU Lesser General Public License for more details.
  *
  *  You should have received a copy of the GNU Lesser General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
 #ifndef KISMAGNETICWORKER_H
 #define KISMAGNETICWORKER_H
 
 #include <kis_paint_device.h>
 #include <kritaselectiontools_export.h>
 
 class KRITASELECTIONTOOLS_EXPORT KisMagneticWorker{
     public:
+        KisMagneticWorker(KisPaintDeviceSP dev, const QRect &rect);
         void run(KisPaintDeviceSP dev, const QRect& rect);
+        void computeEdge(QPoint start, QPoint end);
+
+    private:
+        KisPaintDeviceSP m_dev;
+        const QRect m_rect;
 };
 
 #endif