common/geometry: introducing set-of-polygons class (SHAPE_POLY_SET) and File I/O for shapes class (SHAPE_FILE_IO)

11 years ago · feaa403266
7 changed files with 909 additions and 1 deletions
--- a/common/CMakeLists.txt
+++ b/common/CMakeLists.txt
@ -248,8 +248,11 @@ set( COMMON_SRCS
    tool/context_menu.cpp

    geometry/seg.cpp
+    geometry/shape.cpp
    geometry/shape_line_chain.cpp
+    geometry/shape_poly_set.cpp
    geometry/shape_collisions.cpp
+    geometry/shape_file_io.cpp
    )
 add_library( common STATIC ${COMMON_SRCS} )
 add_dependencies( common lib-dependencies )
--- a/common/geometry/shape.cpp
+++ b/common/geometry/shape.cpp
@ -0,0 +1,38 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2015 CERN
+ * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
+ *
+ * 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, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+
+#include <geometry/shape.h>
+
+bool SHAPE::Parse( std::stringstream& aStream )
+{
+    assert ( false );
+    return false;
+};
+
+const std::string SHAPE::Format( ) const
+{
+    assert ( false );
+    return std::string("");
+};
--- a/common/geometry/shape_file_io.cpp
+++ b/common/geometry/shape_file_io.cpp
@ -0,0 +1,87 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2013 CERN
+ * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
+ *
+ * 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, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+#include <string>
+#include <cassert>
+
+#include <geometry/shape.h>
+#include <geometry/shape_file_io.h>
+
+SHAPE_FILE_IO::SHAPE_FILE_IO( const std::string& aFilename, bool aAppend )
+{
+    m_groupActive = false;
+    m_file = fopen ( aFilename.c_str(), aAppend ? "ab" : "wb" );
+
+    // fixme: exceptions
+}
+
+SHAPE_FILE_IO::~SHAPE_FILE_IO()
+{
+    if(!m_file)
+        return;
+
+    if (m_groupActive)
+        fprintf(m_file,"endgroup\n");
+
+    fclose(m_file);
+}
+
+SHAPE *SHAPE_FILE_IO::Read()
+{
+    assert(false);
+    return NULL;
+}
+
+void SHAPE_FILE_IO::BeginGroup( const std::string aName )
+{
+    if(!m_file)
+        return;
+    fprintf(m_file, "group %s\n", aName.c_str());
+    m_groupActive = true;
+}
+
+void SHAPE_FILE_IO::EndGroup()
+{
+    if(!m_file || !m_groupActive)
+        return;
+
+    fprintf(m_file, "endgroup\n");
+    m_groupActive = false;
+}
+
+void SHAPE_FILE_IO::Write( const SHAPE *aShape, const std::string aName )
+{
+    printf("write %p f %p\n", aShape, m_file );
+
+    if(!m_file)
+        return;
+
+    if(!m_groupActive)
+        fprintf(m_file,"group default\n");
+
+    std::string sh = aShape->Format();
+
+    fprintf(m_file,"shape %d %s %s\n", aShape->Type(), aName.c_str(), sh.c_str() );
+    fflush(m_file);
+}
--- a/common/geometry/shape_poly_set.cpp
+++ b/common/geometry/shape_poly_set.cpp
@ -0,0 +1,580 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2015 CERN
+ * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
+ *
+ * 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, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+
+#include <vector>
+#include <cstdio>
+#include <geometry/shape.h>
+#include <geometry/shape_line_chain.h>
+#include <set>
+#include <list>
+#include <algorithm>
+
+#include <boost/foreach.hpp>
+
+#include "geometry/shape_poly_set.h"
+
+using namespace ClipperLib;
+
+int SHAPE_POLY_SET::NewOutline ()
+{
+    Path empty_path;
+    Paths poly;
+    poly.push_back(empty_path);
+    m_polys.push_back(poly);
+    return m_polys.size() - 1;
+}
+
+int SHAPE_POLY_SET::NewHole( int aOutline )
+{
+    assert(false);
+    return -1;
+}
+
+int SHAPE_POLY_SET::AppendVertex ( int x, int y, int aOutline, int aHole )
+{
+    if(aOutline < 0)
+        aOutline += m_polys.size();
+
+    int idx;
+
+    if(aHole < 0)
+        idx = 0;
+    else
+        idx = aHole + 1;
+
+    assert ( aOutline < (int)m_polys.size() );
+    assert ( idx < (int)m_polys[aOutline].size() );
+
+    m_polys[aOutline][idx].push_back( IntPoint( x, y ) );
+
+    return m_polys[aOutline][idx].size();
+}
+
+int SHAPE_POLY_SET::VertexCount ( int aOutline , int aHole  ) const
+{
+    if(aOutline < 0)
+        aOutline += m_polys.size();
+
+    int idx;
+
+    if(aHole < 0)
+        idx = 0;
+    else
+        idx = aHole + 1;
+
+    assert ( aOutline < (int)m_polys.size() );
+    assert ( idx < (int)m_polys[aOutline].size() );
+
+    return m_polys[aOutline][idx].size();
+}
+
+const VECTOR2I SHAPE_POLY_SET::GetVertex ( int index, int aOutline , int aHole ) const
+{
+    if(aOutline < 0)
+        aOutline += m_polys.size();
+
+    int idx;
+
+    if(aHole < 0)
+        idx = 0;
+    else
+        idx = aHole + 1;
+
+    assert ( aOutline < (int)m_polys.size() );
+    assert ( idx < (int)m_polys[aOutline].size() );
+
+    IntPoint p = m_polys[aOutline][idx][index];
+    return VECTOR2I (p.X, p.Y);
+}
+
+int SHAPE_POLY_SET::AddOutline( const SHAPE_LINE_CHAIN& aOutline )
+{
+    assert ( aOutline.IsClosed() );
+
+    Path p = convert ( aOutline );
+    Paths poly;
+
+    if( !Orientation( p ) )
+        ReversePath(p); // outlines are always CW
+
+    poly.push_back( p );
+
+    m_polys.push_back( poly );
+
+    return m_polys.size() - 1;
+}
+
+int SHAPE_POLY_SET::AddHole( const SHAPE_LINE_CHAIN& aHole, int aOutline  )
+{
+    assert ( m_polys.size() );
+    if(aOutline < 0)
+        aOutline += m_polys.size();
+
+    Paths& poly = m_polys[ aOutline ];
+
+    assert ( poly.size() );
+
+    Path p = convert ( aHole );
+    if( Orientation( p ) )
+        ReversePath(p); // holes are always CCW
+
+    poly.push_back( p );
+
+    return poly.size() - 1;
+}
+
+const ClipperLib::Path SHAPE_POLY_SET::convert( const SHAPE_LINE_CHAIN& aPath )
+{
+    Path c_path;
+
+    for(int i = 0; i < aPath.PointCount(); i++)
+    {
+        const VECTOR2I& vertex = aPath.CPoint(i);
+        c_path.push_back(ClipperLib::IntPoint ( vertex.x, vertex.y ) );
+    }
+
+    return c_path;
+}
+
+void SHAPE_POLY_SET::booleanOp( ClipperLib::ClipType type, const SHAPE_POLY_SET& b )
+{
+    Clipper c;
+
+    c.StrictlySimple( true );
+
+    BOOST_FOREACH ( Paths& subject, m_polys )
+    {
+         c.AddPaths(subject, ptSubject, true);
+    }
+
+    BOOST_FOREACH ( const Paths& clip, b.m_polys )
+    {
+        c.AddPaths(clip, ptClip, true);
+    }
+
+    PolyTree solution;
+
+    c.Execute(type, solution, pftNonZero, pftNonZero);
+
+    importTree(&solution);
+}
+
+void SHAPE_POLY_SET::Add( const SHAPE_POLY_SET& b )
+{
+    booleanOp( ctUnion, b );
+}
+
+void SHAPE_POLY_SET::Subtract( const SHAPE_POLY_SET& b )
+{
+    booleanOp( ctDifference, b );
+}
+
+
+void SHAPE_POLY_SET::Erode ( int aFactor )
+{
+    ClipperOffset c;
+
+    BOOST_FOREACH( Paths& p, m_polys )
+        c.AddPaths(p, jtRound, etClosedPolygon );
+
+    PolyTree solution;
+
+    c.Execute ( solution, aFactor );
+
+    m_polys.clear();
+
+    for (PolyNode *n = solution.GetFirst(); n; n = n->GetNext() )
+    {
+        Paths ps;
+        ps.push_back(n->Contour);
+        m_polys.push_back(ps);
+    }
+}
+
+void SHAPE_POLY_SET::importTree ( ClipperLib::PolyTree* tree)
+{
+    m_polys.clear();
+
+    for (PolyNode *n = tree->GetFirst(); n; n = n->GetNext() )
+    {
+        if( !n->IsHole() )
+        {
+            Paths paths;
+            paths.push_back(n->Contour);
+
+            for (unsigned i = 0; i < n->Childs.size(); i++)
+                paths.push_back(n->Childs[i]->Contour);
+            m_polys.push_back(paths);
+        }
+    }
+}
+
+// Polygon fracturing code. Work in progress.
+
+struct FractureEdge
+{
+    FractureEdge(bool connected, Path* owner, int index) :
+        m_connected(connected),
+        m_owner(owner),
+        m_next(NULL)
+    {
+        m_p1 = (*owner)[index];
+        m_p2 = (*owner)[(index + 1) % owner->size()];
+    }
+
+    FractureEdge(int64_t y = 0) :
+        m_connected(false),
+        m_owner(NULL),
+        m_next(NULL)
+    {
+        m_p1.Y = m_p2.Y = y;
+    }
+
+    FractureEdge(bool connected, const IntPoint& p1, const IntPoint& p2) :
+        m_connected(connected),
+        m_owner(NULL),
+        m_p1(p1),
+        m_p2(p2),
+        m_next(NULL)
+    {
+
+    }
+
+    bool matches ( int y ) const
+    {
+        int y_min = std::min(m_p1.Y, m_p2.Y);
+        int y_max = std::max(m_p1.Y, m_p2.Y);
+
+        return (y >= y_min) && (y <= y_max);
+    }
+
+    bool m_connected;
+    Path* m_owner;
+    IntPoint m_p1, m_p2;
+    FractureEdge *m_next;
+};
+
+struct CompareEdges
+{
+    bool operator()(const FractureEdge *a, const FractureEdge *b) const
+    {
+       if( std::min(a->m_p1.Y, a->m_p2.Y) < std::min(b->m_p1.Y, b->m_p2.Y) )
+            return true;
+       return false;
+    }
+};
+
+typedef std::multiset<FractureEdge *, CompareEdges> FractureEdgeSet;
+
+static int processEdge ( FractureEdgeSet& edges, FractureEdge* edge )
+{
+    int n  = 0;
+    int64_t x = edge->m_p1.X;
+    int64_t y = edge->m_p1.Y;
+
+
+    int64_t min_dist_l = std::numeric_limits<int64_t>::max();
+    int64_t min_dist_r = std::numeric_limits<int64_t>::max();
+    int64_t x_nearest_l = 0, x_nearest_r = 0, x_nearest;
+
+ // fixme: search edges in sorted multiset
+ // FractureEdge comp_min( std::min(edge->m_p1.Y, edge->m_p2.Y) );
+ // FractureEdgeSet::iterator e_begin = edges.lower_bound ( &comp_min );
+
+    FractureEdgeSet::iterator e_nearest_l = edges.end(), e_nearest_r = edges.end(), e_nearest;
+
+
+    for(FractureEdgeSet::iterator i = edges.begin() ; i != edges.end(); ++i)
+    {
+        n++;
+        if( (*i)->matches(y) )
+        {
+            int64_t x_intersect;
+            if( (*i)->m_p1.Y == (*i)->m_p2.Y ) // horizontal edge
+                x_intersect = std::max ( (*i)->m_p1.X, (*i)->m_p2.X );
+            else
+                x_intersect = (*i)->m_p1.X + rescale((*i)->m_p2.X - (*i)->m_p1.X,   y - (*i)->m_p1.Y,   (*i)->m_p2.Y - (*i)->m_p1.Y );
+
+            int64_t dist = (x - x_intersect);
+
+            if(dist > 0 && dist < min_dist_l)
+            {
+                min_dist_l = dist;
+                x_nearest_l = x_intersect;
+                e_nearest_l = i;
+            }
+
+            if(dist <= 0 && (-dist) < min_dist_r)
+            {
+                min_dist_r = -dist;
+                x_nearest_r = x_intersect;
+                e_nearest_r = i;
+            }
+        }
+    }
+
+    if(e_nearest_l != edges.end() || e_nearest_r != edges.end())
+    {
+        if( e_nearest_l !=edges.end() && ( (*e_nearest_l)->m_connected || ((*e_nearest_l) ->m_owner != edge->m_owner )))
+        {
+            e_nearest = e_nearest_l;
+            x_nearest = x_nearest_l;
+        }
+        else if( e_nearest_r !=edges.end() && ( (*e_nearest_r)->m_connected || ((*e_nearest_r) ->m_owner != edge->m_owner ) )) {
+            e_nearest = e_nearest_r;
+            x_nearest = x_nearest_r;
+        }
+        else
+            return 0;
+
+        FractureEdge split_1 ( true, (*e_nearest)->m_p1, IntPoint(x_nearest, y) );
+        FractureEdge *lead1 = new FractureEdge(true, IntPoint(x_nearest, y), IntPoint(x, y) );
+        FractureEdge *lead2 = new FractureEdge(true, IntPoint(x, y), IntPoint(x_nearest, y) );
+        FractureEdge *split_2 = new FractureEdge ( true, IntPoint(x_nearest, y), (*e_nearest)->m_p2 );
+
+        edges.insert(split_2);
+        edges.insert(lead1);
+        edges.insert(lead2);
+
+        FractureEdge* link = (*e_nearest)->m_next;
+
+        (*e_nearest)->m_p1 = split_1.m_p1;
+        (*e_nearest)->m_p2 = IntPoint(x_nearest, y);
+        (*e_nearest)->m_connected = true;//split_1->m_connected;
+        (*e_nearest)->m_next = lead1;
+        lead1->m_next = edge;
+
+        FractureEdge *last;
+        for(last = edge; last->m_next != edge; last = last->m_next)
+        {
+            last->m_connected = true;
+            last->m_owner = NULL;
+        }
+
+        last->m_owner = NULL;
+        last->m_connected = true;
+        last->m_next = lead2;
+        lead2->m_next = split_2;
+        split_2->m_next = link;
+
+        return 1;
+    }
+
+    return 0;
+}
+
+void SHAPE_POLY_SET::fractureSingle( ClipperLib::Paths& paths )
+{
+    FractureEdgeSet edges;
+    FractureEdge *root = NULL;
+
+    bool first = true;
+
+    if(paths.size() == 1)
+        return;
+
+    int num_unconnected = 0;
+
+    BOOST_FOREACH(Path& path, paths)
+    {
+        int index = 0;
+
+        FractureEdge *prev = NULL, *first_edge = NULL;
+        for(unsigned i = 0; i < path.size(); i++)
+        {
+            FractureEdge *fe = new FractureEdge ( first, &path, index++ );
+
+            if(!root)
+                root = fe;
+
+            if(!first_edge)
+                first_edge = fe;
+            if(prev)
+                prev->m_next = fe;
+
+            if(i == path.size() - 1)
+                fe->m_next = first_edge;
+
+            prev = fe;
+            edges.insert ( fe );
+
+            if(!fe->m_connected)
+                num_unconnected++;
+        }
+
+        first = false; // first path is always the outline
+    }
+
+    while(1)
+    {
+        bool found = false;
+
+        for(FractureEdgeSet::iterator i = edges.begin(); i != edges.end(); ++i )
+        {
+            if(!(*i)->m_connected)
+            {
+                if (processEdge ( edges, *i ) > 0)
+                    found = true;
+            }
+        }
+        if(!found)
+            break;
+    }
+
+    IntPoint prev = root->m_p1;
+    paths.clear();
+    Path newPath;
+    newPath.push_back(prev);
+    FractureEdge *e;
+    IntPoint p;
+
+    for( e = root; e->m_next != root; e=e->m_next)
+    {
+        p = e->m_p1;
+        newPath.push_back(p);
+        prev = p;
+        delete e;
+    }
+
+    p = e->m_p1;
+
+    delete e;
+    newPath.push_back(p);
+    paths.push_back(newPath);
+}
+
+void SHAPE_POLY_SET::Fracture ()
+{
+    BOOST_FOREACH(Paths& paths, m_polys)
+    {
+        fractureSingle( paths );
+    }
+}
+
+void SHAPE_POLY_SET::Simplify()
+{
+    for (unsigned i = 0; i < m_polys.size(); i++)
+    {
+        Paths out;
+        SimplifyPolygons(m_polys[i], out, pftNonZero);
+        m_polys[i] = out;
+    }
+}
+
+const std::string SHAPE_POLY_SET::Format() const
+{
+    std::stringstream ss;
+
+    ss << "polyset " << m_polys.size() << "\n";
+
+    for( unsigned i = 0; i < m_polys.size(); i++ )
+    {
+        ss << "poly " << m_polys[i].size() << "\n";
+        for( unsigned j = 0; j < m_polys[i].size(); j++)
+        {
+            ss << m_polys[i][j].size() << "\n";
+            for( unsigned v = 0; v < m_polys[i][j].size(); v++)
+                ss << m_polys[i][j][v].X << " " << m_polys[i][j][v].Y << "\n";
+        }
+        ss << "\n";
+    }
+
+    return ss.str();
+}
+
+bool SHAPE_POLY_SET::Parse( std::stringstream& aStream )
+{
+    std::string tmp;
+
+    aStream >> tmp;
+
+    if(tmp != "polyset")
+        return false;
+
+    aStream >> tmp;
+
+    unsigned int n_polys = atoi( tmp.c_str() );
+    if(n_polys < 0)
+        return false;
+
+    for( unsigned i = 0; i < n_polys; i++ )
+    {
+        ClipperLib::Paths paths;
+
+        aStream >> tmp;
+        if(tmp != "poly")
+            return false;
+
+        aStream >> tmp;
+        unsigned int n_outlines = atoi( tmp.c_str() );
+        if(n_outlines < 0)
+            return false;
+
+        for( unsigned j = 0; j < n_outlines; j++)
+        {
+            ClipperLib::Path outline;
+
+            aStream >> tmp;
+            unsigned int n_vertices = atoi( tmp.c_str() );
+            for( unsigned v = 0; v < n_vertices; v++)
+            {
+                ClipperLib::IntPoint p;
+
+                aStream >> tmp; p.X = atoi ( tmp.c_str() );
+                aStream >> tmp; p.Y = atoi ( tmp.c_str() );
+                outline.push_back(p);
+            }
+            paths.push_back(outline);
+        }
+        m_polys.push_back(paths);
+    }
+    return true;
+}
+
+const BOX2I SHAPE_POLY_SET::BBox( int aClearance ) const
+{
+    BOX2I bb;
+    bool first = true;
+
+    for( unsigned i = 0; i < m_polys.size(); i++ )
+    {
+        for( unsigned j = 0; j < m_polys[i].size(); j++)
+        {
+            for( unsigned v = 0; v < m_polys[i][j].size(); v++)
+            {
+                VECTOR2I p( m_polys[i][j][v].X, m_polys[i][j][v].Y );
+                if(first)
+                    bb =  BOX2I(p, VECTOR2I(0, 0));
+                else
+                    bb.Merge (p);
+
+                first = false;
+            }
+        }
+    }
+
+    bb.Inflate( aClearance );
+    return bb;
+}
--- a/include/geometry/shape.h
+++ b/include/geometry/shape.h
@ -25,6 +25,9 @@
 #ifndef __SHAPE_H
 #define __SHAPE_H

+#include <string>
+#include <sstream>
+
 #include <math/vector2d.h>
 #include <math/box2.h>

@ -42,7 +45,7 @@ enum SHAPE_TYPE
    SH_LINE_CHAIN,      ///> line chain (polyline)
    SH_CIRCLE,          ///> circle
    SH_CONVEX,          ///> convex polygon
-    SH_POLYGON,         ///> any polygon (with holes, etc.)
+    SH_POLY_SET,         ///> any polygon (with holes, etc.)
    SH_COMPOUND         ///> compound shape, consisting of multiple simple shapes
 };

@ -153,6 +156,10 @@ public:

    virtual bool IsSolid() const = 0;

+    virtual bool Parse( std::stringstream& aStream );
+
+    virtual const std::string Format( ) const;
+
 protected:
    ///> type of our shape
    SHAPE_TYPE m_type;
--- a/include/geometry/shape_file_io.h
+++ b/include/geometry/shape_file_io.h
@ -0,0 +1,61 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2015 CERN
+ * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
+ *
+ * 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, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+
+#ifndef __SHAPE_FILE_IO_H
+#define __SHAPE_FILE_IO_H
+
+#include <cstdio>
+
+class SHAPE;
+
+/**
+ * Class SHAPE_FILE_IO
+ *
+ * Helper class for saving/loading shapes from a file.
+ */
+class SHAPE_FILE_IO
+{
+    public:
+        SHAPE_FILE_IO ( const std::string& aFilename, bool aAppend = false );
+        ~SHAPE_FILE_IO ( );
+
+        void BeginGroup( const std::string aName = "<noname>");
+        void EndGroup( );
+
+        SHAPE *Read();
+
+        void Write ( const SHAPE *aShape, const std::string aName = "<noname>");
+
+        void Write ( const SHAPE &aShape, const std::string aName = "<noname>")
+        {
+            Write( &aShape, aName );
+        };
+
+    private:
+        FILE *m_file;
+        bool m_groupActive;
+};
+
+#endif
--- a/include/geometry/shape_poly_set.h
+++ b/include/geometry/shape_poly_set.h
@ -0,0 +1,132 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2015 CERN
+ * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
+ *
+ * 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, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+#ifndef __SHAPE_POLY_SET_H
+#define __SHAPE_POLY_SET_H
+
+#include <vector>
+#include <cstdio>
+#include <geometry/shape.h>
+#include <geometry/shape_line_chain.h>
+
+#include "clipper.hpp"
+
+/**
+ * Class SHAPE_POLY_SET
+ *
+ * Represents a set of closed polygons. Polygons may be nonconvex, self-intersecting
+ * and have holes. Provides boolean operations (using Clipper library as the backend).
+ *
+ * TODO: document, derive from class SHAPE, add convex partitioning & spatial index
+ */
+class SHAPE_POLY_SET : public SHAPE
+{
+    public:
+        SHAPE_POLY_SET() : SHAPE (SH_POLY_SET) {};
+        ~SHAPE_POLY_SET() {};
+
+        ///> Creates a new empty polygon in the set and returns its index
+        int NewOutline ();
+
+        ///> Cretes a new empty hole in the given outline (default: last one) and returns its index
+        int NewHole( int aOutline = -1);
+
+        ///> Adds a new outline to the set and returns its index
+        int AddOutline ( const SHAPE_LINE_CHAIN& aOutline );
+
+        ///> Adds a new hole to the given outline (default: last) and returns its index
+        int AddHole ( const SHAPE_LINE_CHAIN& aHole, int aOutline = -1 );
+
+        ///> Appends a vertex at the end of the given outline/hole (default: last hole in the last outline)
+        int AppendVertex ( int x, int y, int aOutline = -1, int aHole = -1 );
+
+        ///> Returns the index-th vertex in a given hole outline within a given outline
+        const VECTOR2I GetVertex ( int index, int aOutline = -1, int aHole = -1) const;
+
+        ///> Returns true if any of the outlines is self-intersecting
+        bool IsSelfIntersecting();
+
+        ///> Returns the number of outlines in the set
+        int OutlineCount() const { return m_polys.size(); }
+
+        ///> Returns the number of vertices in a given outline/hole
+        int VertexCount ( int aOutline = -1, int aHole = -1 ) const;
+
+        ///> Returns the internal representation (ClipperLib) of a given polygon (outline + holes)
+        const ClipperLib::Paths& GetPoly ( int aIndex ) const
+        {
+            return m_polys[aIndex];
+        }
+
+        ///> Performs boolean polyset difference
+        void Subtract( const SHAPE_POLY_SET& b );
+
+        ///> Performs boolean polyset union
+        void Add( const SHAPE_POLY_SET& b );
+
+        ///> Performs smooth outline inflation (Minkowski sum of the outline and a circle of a given radius)
+        void SmoothInflate ( int aFactor );
+
+        ///> Performs outline erosion/shrinking
+        void Erode ( int aFactor );
+
+        ///> Converts a set of polygons with holes to a singe outline with 'slits'/'fractures' connecting the outer ring
+        ///> to the inner holes
+        void Fracture ();
+
+        ///> Simplifies the polyset (merges overlapping polys, eliminates degeneracy/self-intersections)
+        void Simplify ();
+
+        /// @copydoc SHAPE::Format()
+        const std::string Format() const;
+
+        /// @copydoc SHAPE::Parse()
+        bool Parse( std::stringstream& aStream );
+
+        void  Move( const VECTOR2I& aVector ) { assert(false ); };
+
+        bool IsSolid() const
+        {
+            return true;
+        }
+
+        const BOX2I BBox( int aClearance = 0 ) const;
+
+        bool Collide( const VECTOR2I& aP, int aClearance = 0 ) const { return false; }
+        bool Collide( const SEG& aSeg, int aClearance = 0 ) const { return false; }
+
+    private:
+
+        void fractureSingle( ClipperLib::Paths& paths );
+        void importTree ( ClipperLib::PolyTree* tree);
+        void booleanOp( ClipperLib::ClipType type, const SHAPE_POLY_SET& b );
+
+        const ClipperLib::Path convert( const SHAPE_LINE_CHAIN& aPath );
+
+        typedef std::vector<ClipperLib::Paths> Polyset;
+
+        Polyset m_polys;
+};
+
+#endif