kicad/libs/kimath/include/geometry/shape_line_chain.h

/*
 * 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>
 * Copyright (C) 2013-2020 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * 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_LINE_CHAIN
#define __SHAPE_LINE_CHAIN


#include <clipper.hpp>
#include <geometry/seg.h>
#include <geometry/shape.h>
#include <geometry/shape_arc.h>
#include <math/vector2d.h>


/**
 * SHAPE_LINE_CHAIN
 *
 * Represents a polyline (an zero-thickness chain of connected line segments).
 * I purposedly didn't name it "polyline" to avoid confusion with the existing CPolyLine
 * in pcbnew.
 *
 * SHAPE_LINE_CHAIN class shall not be used for polygons!
 */
class SHAPE_LINE_CHAIN : public SHAPE_LINE_CHAIN_BASE
{
private:
    typedef std::vector<VECTOR2I>::iterator point_iter;
    typedef std::vector<VECTOR2I>::const_iterator point_citer;

public:
    /**
     * Struct INTERSECTION
     *
     * Represents an intersection between two line segments
     */
    struct INTERSECTION
    {
        /// segment belonging from the (this) argument of Intersect()
        SEG our;
        /// segment belonging from the aOther argument of Intersect()
        SEG their;
        /// point of intersection between our and their.
        VECTOR2I p;
    };


    /**
     * Class POINT_INSIDE_TRACKER
     * 
     * A dynamic state checking if a point lies within polygon with a dynamically built outline (
     * with each piece of the outline added by AddPolyline ()
     */
    class POINT_INSIDE_TRACKER
    {
    public:
        POINT_INSIDE_TRACKER( const VECTOR2I& aPoint );

        void AddPolyline( const SHAPE_LINE_CHAIN& aPolyline );
        bool IsInside();

    private:

        bool processVertex ( const VECTOR2I& ip, const VECTOR2I& ipNext );

        VECTOR2I m_point;
        VECTOR2I m_lastPoint;
        VECTOR2I m_firstPoint;
        bool m_finished;
        int m_state;
        int m_count;
    };

    typedef std::vector<INTERSECTION> INTERSECTIONS;


    /**
     * Constructor
     * Initializes an empty line chain.
     */
    SHAPE_LINE_CHAIN() : SHAPE_LINE_CHAIN_BASE( SH_LINE_CHAIN ), m_closed( false ), m_width( 0 )
    {}

    /**
     * Copy Constructor
     */

    SHAPE_LINE_CHAIN( const SHAPE_LINE_CHAIN& aShape )
            : SHAPE_LINE_CHAIN_BASE( SH_LINE_CHAIN ),
              m_points( aShape.m_points ),
              m_shapes( aShape.m_shapes ),
              m_arcs( aShape.m_arcs ),
              m_closed( aShape.m_closed ),
              m_width( aShape.m_width ),
              m_bbox( aShape.m_bbox )
    {}

    SHAPE_LINE_CHAIN( const std::vector<int>& aV);

    SHAPE_LINE_CHAIN( const std::vector<wxPoint>& aV, bool aClosed = false )
            : SHAPE_LINE_CHAIN_BASE( SH_LINE_CHAIN ), m_closed( aClosed ), m_width( 0 )
    {
        m_points.reserve( aV.size() );

        for( auto pt : aV )
            m_points.emplace_back( pt.x, pt.y );

        m_shapes = std::vector<ssize_t>( aV.size(), ssize_t( SHAPE_IS_PT ) );
    }

    SHAPE_LINE_CHAIN( const std::vector<VECTOR2I>& aV, bool aClosed = false )
            : SHAPE_LINE_CHAIN_BASE( SH_LINE_CHAIN ), m_closed( aClosed ), m_width( 0 )
    {
        m_points = aV;
        m_shapes = std::vector<ssize_t>( aV.size(), ssize_t( SHAPE_IS_PT ) );
    }

    SHAPE_LINE_CHAIN( const SHAPE_ARC& aArc, bool aClosed = false )
            : SHAPE_LINE_CHAIN_BASE( SH_LINE_CHAIN ),
              m_closed( aClosed ),
              m_width( 0 )
    {
        m_points = aArc.ConvertToPolyline().CPoints();
        m_arcs.emplace_back( aArc );
        m_shapes = std::vector<ssize_t>( m_points.size(), 0 );
    }

    SHAPE_LINE_CHAIN( const ClipperLib::Path& aPath ) :
        SHAPE_LINE_CHAIN_BASE( SH_LINE_CHAIN ),
        m_closed( true ),
        m_width( 0 )
    {
        m_points.reserve( aPath.size() );
        m_shapes = std::vector<ssize_t>( aPath.size(), ssize_t( SHAPE_IS_PT ) );

        for( const auto& point : aPath )
            m_points.emplace_back( point.X, point.Y );
    }

    virtual ~SHAPE_LINE_CHAIN()
    {}

    SHAPE_LINE_CHAIN& operator=(const SHAPE_LINE_CHAIN&) = default;

    SHAPE* Clone() const override;

    /**
     * Function Clear()
     * Removes all points from the line chain.
     */
    void Clear()
    {
        m_points.clear();
        m_arcs.clear();
        m_shapes.clear();
        m_closed = false;
    }

    /**
     * Function SetClosed()
     *
     * Marks the line chain as closed (i.e. with a segment connecting the last point with
     * the first point).
     * @param aClosed: whether the line chain is to be closed or not.
     */
    void SetClosed( bool aClosed )
    {
        m_closed = aClosed;
    }

    /**
     * Function IsClosed()
     *
     * @return aClosed: true, when our line is closed.
     */
    bool IsClosed() const override
    {
        return m_closed;
    }

    /**
     * Sets the width of all segments in the chain
     * @param aWidth width in internal units
     */
    void SetWidth( int aWidth )
    {
        m_width = aWidth;
    }

    /**
     * Gets the current width of the segments in the chain
     * @return width in internal units
     */
    int Width() const
    {
        return m_width;
    }

    /**
     * Function SegmentCount()
     *
     * Returns number of segments in this line chain.
     * @return number of segments
     */
    int SegmentCount() const
    {
        int c = m_points.size() - 1;
        if( m_closed )
            c++;

        return std::max( 0, c );
    }

    /**
     * Returns the number of shapes (line segments or arcs) in this line chain.
     * This is kind of like SegmentCount() but will only count arcs as 1 segment
     * @return ArcCount() + the number of non-arc segments
     */
    int ShapeCount() const;

    /**
     * Function PointCount()
     *
     * Returns the number of points (vertices) in this line chain
     * @return number of points
     */
    int PointCount() const
    {
        return m_points.size();
    }

    /**
     * Function Segment()
     *
     * Returns a copy of the aIndex-th segment in the line chain.
     * @param aIndex: index of the segment in the line chain. Negative values are counted from
     * the end (i.e. -1 means the last segment in the line chain)
     * @return SEG - aIndex-th segment in the line chain
     */
    SEG Segment( int aIndex )
    {
        if( aIndex < 0 )
            aIndex += SegmentCount();

        if( aIndex == (int)( m_points.size() - 1 ) && m_closed )
            return SEG( m_points[aIndex], m_points[0], aIndex );
        else
            return SEG( m_points[aIndex], m_points[aIndex + 1], aIndex );
    }

    /**
     * Function CSegment()
     *
     * Returns a constant copy of the aIndex-th segment in the line chain.
     * @param aIndex: index of the segment in the line chain. Negative values are counted from
     * the end (i.e. -1 means the last segment in the line chain)
     * @return const SEG - aIndex-th segment in the line chain
     */
    const SEG CSegment( int aIndex ) const
    {
        if( aIndex < 0 )
            aIndex += SegmentCount();

        if( aIndex == (int)( m_points.size() - 1 ) && m_closed )
            return SEG( m_points[aIndex], m_points[0], aIndex );
        else
            return SEG( m_points[aIndex], m_points[aIndex + 1], aIndex );
    }

    /**
     * Returns the vertex index of the next shape in the chain, or -1 if aPoint is in the last shape
     * If aPoint is the start of a segment, this will be ( aPoint + 1 ).
     * If aPoint is part of an arc, this will be the index of the start of the next shape after the
     * arc, in other words, the last point of the arc.
     * @param aPointIndex is a vertex in the chain
     * @param aForwards is true if the next shape is desired, false for previous shape
     * @return the vertex index of the start of the next shape after aPoint's shape
     */
    int NextShape( int aPointIndex, bool aForwards = true ) const;

    int PrevShape( int aPointIndex ) const
    {
        return NextShape( aPointIndex, false );
    }

    /**
     * Accessor Function to move a point to a specific location
     * @param aIndex Index (wrapping) of the point to move
     * @param aPos New absolute location of the point
     */
    void SetPoint( int aIndex, const VECTOR2I& aPos )
    {
        if( aIndex < 0 )
            aIndex += PointCount();
        else if( aIndex >= PointCount() )
            aIndex -= PointCount();

        m_points[aIndex] = aPos;

        if( m_shapes[aIndex] != SHAPE_IS_PT )
            convertArc( m_shapes[aIndex] );
    }

    /**
     * Function Point()
     *
     * Returns a const reference to a given point in the line chain.
     * @param aIndex index of the point
     * @return const reference to the point
     */
    const VECTOR2I& CPoint( int aIndex ) const
    {
        if( aIndex < 0 )
            aIndex += PointCount();
        else if( aIndex >= PointCount() )
            aIndex -= PointCount();

        return m_points[aIndex];
    }

    const std::vector<VECTOR2I>& CPoints() const
    {
        return m_points;
    }

    /**
     * Returns the last point in the line chain.
     */
    const VECTOR2I& CLastPoint() const
    {
        return m_points[PointCount() - 1];
    }

    /**
     * @return the vector of stored arcs
     */
    const std::vector<SHAPE_ARC>& CArcs() const
    {
        return m_arcs;
    }

    /**
     * @return the vector of values indicating shape type and location
     */
    const std::vector<ssize_t>& CShapes() const
    {
        return m_shapes;
    }

    /// @copydoc SHAPE::BBox()
    const BOX2I BBox( int aClearance = 0 ) const override
    {
        BOX2I bbox;
        bbox.Compute( m_points );

        if( aClearance != 0 || m_width != 0 )
            bbox.Inflate( aClearance + m_width );

        return bbox;
    }

    void GenerateBBoxCache() const
    {
        m_bbox.Compute( m_points );

        if( m_width != 0 )
            m_bbox.Inflate( m_width );
    }

    const BOX2I BBoxFromCache() const
    {
        return m_bbox;
    }

    /**
     * Function Distance()
     *
     * Computes the minimum distance between the line chain and a point aP.
     * @param aP the point
     * @return minimum distance.
     */
    int Distance( const VECTOR2I& aP, bool aOutlineOnly = false ) const;

    /**
     * Function Reverse()
     *
     * Reverses point order in the line chain.
     * @return line chain with reversed point order (original A-B-C-D: returned D-C-B-A)
     */
    const SHAPE_LINE_CHAIN Reverse() const;

    /**
     * Function Length()
     *
     * Returns length of the line chain in Euclidean metric.
     * @return length of the line chain
     */
    long long int Length() const;

    /**
     * Function Append()
     *
     * Appends a new point at the end of the line chain.
     * @param aX is X coordinate of the new point
     * @param aY is Y coordinate of the new point
     * @param aAllowDuplication = true to append the new point
     * even it is the same as the last entered point
     * false (default) to skip it if it is the same as the last entered point
     */
    void Append( int aX, int aY, bool aAllowDuplication = false )
    {
        VECTOR2I v( aX, aY );
        Append( v, aAllowDuplication );
    }

    /**
     * Function Append()
     *
     * Appends a new point at the end of the line chain.
     * @param aP the new point
     * @param aAllowDuplication = true to append the new point
     * even it is the same as the last entered point
     * false (default) to skip it if it is the same as the last entered point
     */
    void Append( const VECTOR2I& aP, bool aAllowDuplication = false )
    {
        if( m_points.size() == 0 )
            m_bbox = BOX2I( aP, VECTOR2I( 0, 0 ) );

        if( m_points.size() == 0 || aAllowDuplication || CPoint( -1 ) != aP )
        {
            m_points.push_back( aP );
            m_shapes.push_back( ssize_t( SHAPE_IS_PT ) );
            m_bbox.Merge( aP );
        }
    }

    /**
     * Function Append()
     *
     * Appends another line chain at the end.
     * @param aOtherLine the line chain to be appended.
     */
    void Append( const SHAPE_LINE_CHAIN& aOtherLine );

    void Append( const SHAPE_ARC& aArc );

    void Insert( size_t aVertex, const VECTOR2I& aP );

    void Insert( size_t aVertex, const SHAPE_ARC& aArc );

    /**
     * Function Replace()
     *
     * Replaces points with indices in range [start_index, end_index] with a single point aP.
     * @param aStartIndex start of the point range to be replaced (inclusive)
     * @param aEndIndex end of the point range to be replaced (inclusive)
     * @param aP replacement point
     */
    void Replace( int aStartIndex, int aEndIndex, const VECTOR2I& aP );

    /**
     * Function Replace()
     *
     * Replaces points with indices in range [start_index, end_index] with the points from line
     * chain aLine.
     * @param aStartIndex start of the point range to be replaced (inclusive)
     * @param aEndIndex end of the point range to be replaced (inclusive)
     * @param aLine replacement line chain.
     */
    void Replace( int aStartIndex, int aEndIndex, const SHAPE_LINE_CHAIN& aLine );

    /**
     * Function Remove()
     *
     * Removes the range of points [start_index, end_index] from the line chain.
     * @param aStartIndex start of the point range to be replaced (inclusive)
     * @param aEndIndex end of the point range to be replaced (inclusive)
     */
    void Remove( int aStartIndex, int aEndIndex );

    /**
     * Function Remove()
     * removes the aIndex-th point from the line chain.
     * @param aIndex is the index of the point to be removed.
     */
    void Remove( int aIndex )
    {
        Remove( aIndex, aIndex );
    }

    /**
     * Removes the shape at the given index from the line chain.
     * If the given index is inside an arc, the entire arc will be removed.
     * Otherwise this is equivalent to Remove( aPointIndex ).
     * @param aPointIndex is the index of the point to remove
     */
    void RemoveShape( int aPointIndex );

    /**
     * Function Split()
     *
     * Inserts the point aP belonging to one of the our segments, splitting the adjacent segment
     * in two.
     * @param aP the point to be inserted
     * @return index of the newly inserted point (or a negative value if aP does not lie on
     * our line)
     */
    int Split( const VECTOR2I& aP );

    /**
     * Function Find()
     *
     * Searches for point aP.
     * @param aP the point to be looked for
     * @return index of the correspoinding point in the line chain or negative when not found.
     */
    int Find( const VECTOR2I& aP ) const;

    /**
     * Function FindSegment()
     *
     * Searches for segment containing point aP.
     * @param aP the point to be looked for
     * @return index of the correspoinding segment in the line chain or negative when not found.
     */
    int FindSegment( const VECTOR2I& aP ) const;

    /**
     * Function Slice()
     *
     * Returns a subset of this line chain containing the [start_index, end_index] range of points.
     * @param aStartIndex start of the point range to be returned (inclusive)
     * @param aEndIndex end of the point range to be returned (inclusive)
     * @return cut line chain.
     */
    const SHAPE_LINE_CHAIN Slice( int aStartIndex, int aEndIndex = -1 ) const;

    struct compareOriginDistance
    {
        compareOriginDistance( const VECTOR2I& aOrigin ):
            m_origin( aOrigin )
        {}

        bool operator()( const INTERSECTION& aA, const INTERSECTION& aB )
        {
            return ( m_origin - aA.p ).EuclideanNorm() < ( m_origin - aB.p ).EuclideanNorm();
        }

        VECTOR2I m_origin;
    };

    bool Intersects( const SHAPE_LINE_CHAIN& aChain ) const;

    /**
     * Function Intersect()
     *
     * Finds all intersection points between our line chain and the segment aSeg.
     * @param aSeg the segment chain to find intersections with
     * @param aIp reference to a vector to store found intersections. Intersection points are
     * sorted with increasing distances from point aSeg.a.
     * @return number of intersections found
     */
    int Intersect( const SEG& aSeg, INTERSECTIONS& aIp ) const;

    /**
     * Function Intersect()
     *
     * Finds all intersection points between our line chain and the line chain aChain.
     * @param aChain the line chain to find intersections with
     * @param aIp reference to a vector to store found intersections. Intersection points are
     * sorted with increasing path lengths from the starting point of aChain.
     * @return number of intersections found
     */
    int Intersect( const SHAPE_LINE_CHAIN& aChain, INTERSECTIONS& aIp ) const;

    /**
     * Function PathLength()
     *
     * Computes the walk path length from the beginning of the line chain and the point aP
     * belonging to our line.
     * @return: path length in Euclidean metric or -1 if aP does not belong to the line chain.
     */
    int PathLength( const VECTOR2I& aP ) const;

    /**
     * Function CheckClearance()
     *
     * Checks if point aP is closer to (or on) an edge or vertex of the line chain.
     * @param aP point to check
     * @param aDist distance in internal units
     * @return true if the point is equal to or closer than aDist to the line chain.
     */
    bool CheckClearance( const VECTOR2I& aP, const int aDist) const;

    /**
     * Function SelfIntersecting()
     *
     * Checks if the line chain is self-intersecting.
     * @return (optional) first found self-intersection point.
     */
    const OPT<INTERSECTION> SelfIntersecting() const;

    /**
     * Function Simplify()
     *
     * Simplifies the line chain by removing colinear adjacent segments and duplicate vertices.
     * @param aRemoveColinear controsl the removal of colinear adjacent segments
     * @return reference to self.
     */
    SHAPE_LINE_CHAIN& Simplify( bool aRemoveColinear = true );

    /**
     * Converts an arc to only a point chain by removing the arc and references
     *
     * @param aArcIndex index of the arc to convert to points
     */
    void convertArc( ssize_t aArcIndex );

    /**
     * Creates a new Clipper path from the SHAPE_LINE_CHAIN in a given orientation
     */
    ClipperLib::Path convertToClipper( bool aRequiredOrientation ) const;

    /**
     * Find the segment nearest the given point.
     *
     * @param aP point to compare with
     * @return the index of the segment closest to the point
     */
    int NearestSegment( const VECTOR2I& aP ) const;

    /**
     * Finds a point on the line chain that is closest to point aP.
     * @param aP is the point to find
     * @param aAllowInternalShapePoints if false will not return points internal to an arc (i.e.
     *                                  only the arc endpoints are possible candidates)
     * @return the nearest point.
     */
    const VECTOR2I NearestPoint( const VECTOR2I& aP, bool aAllowInternalShapePoints = true ) const;

    /**
     * Finds a point on the line chain that is closest to the line defined by the points of
     * segment aSeg, also returns the distance.
     * @param aSeg Segment defining the line.
     * @param dist reference receiving the distance to the nearest point.
     * @return the nearest point.
     */
    const VECTOR2I NearestPoint( const SEG& aSeg, int& dist ) const;

    /// @copydoc SHAPE::Format()
    const std::string Format() const override;

    /// @copydoc SHAPE::Parse()
    bool Parse( std::stringstream& aStream ) override;

    bool operator!=( const SHAPE_LINE_CHAIN& aRhs ) const
    {
        if( PointCount() != aRhs.PointCount() )
            return true;

        for( int i = 0; i < PointCount(); i++ )
        {
            if( CPoint( i ) != aRhs.CPoint( i ) )
                return true;
        }

        return false;
    }

    bool CompareGeometry( const SHAPE_LINE_CHAIN& aOther ) const;

    void Move( const VECTOR2I& aVector ) override
    {
        for( auto& pt : m_points )
            pt += aVector;

        for( auto& arc : m_arcs )
            arc.Move( aVector );
    }

    /**
     * Mirrors the line points about y or x (or both)
     * @param aX If true, mirror about the y axis (flip X coordinate)
     * @param aY If true, mirror about the x axis (flip Y coordinate)
     * @param aRef sets the reference point about which to mirror
     */
    void Mirror( bool aX = true, bool aY = false, const VECTOR2I& aRef = { 0, 0 } );

    /**
     * Function Rotate
     * rotates all vertices by a given angle
     * @param aCenter is the rotation center
     * @param aAngle rotation angle in radians
     */
    void Rotate( double aAngle, const VECTOR2I& aCenter = VECTOR2I( 0, 0 ) ) override;

    bool IsSolid() const override
    {
        return false;
    }

    const VECTOR2I PointAlong( int aPathLength ) const;

    double Area() const;

    size_t ArcCount() const
    {
        return m_arcs.size();
    }

    ssize_t ArcIndex( size_t aSegment ) const
    {
        if( aSegment >= m_shapes.size() )
            return SHAPE_IS_PT;

        return m_shapes[aSegment];
    }

    const SHAPE_ARC& Arc( size_t aArc ) const
    {
        return m_arcs[aArc];
    }

    bool isArc( size_t aSegment ) const
    {
        /**
         * A segment is part of an arc except in the special case of two arcs next to each other
         * but without a shared vertex.  Here there is a segment between the end of the first arc
         * and the start of the second arc.
         */
        return ( aSegment < m_shapes.size() - 1
                 && m_shapes[aSegment] != SHAPE_IS_PT
                 && m_shapes[aSegment] == m_shapes[aSegment + 1] );
    }

    virtual const VECTOR2I GetPoint( int aIndex ) const override { return CPoint(aIndex); }
    virtual const SEG GetSegment( int aIndex ) const override { return CSegment(aIndex); }
    virtual size_t GetPointCount() const override { return PointCount(); }
    virtual size_t GetSegmentCount() const override { return SegmentCount(); }

private:

    constexpr static ssize_t SHAPE_IS_PT = -1;

    /// array of vertices
    std::vector<VECTOR2I> m_points;

    /**
     * Array of indices that refer to the index of the shape if the point is part of a larger
     * shape, e.g. arc or spline.
     * If the value is -1, the point is just a point.
     */
    std::vector<ssize_t> m_shapes;

    std::vector<SHAPE_ARC> m_arcs;

    /// is the line chain closed?
    bool m_closed;

    /// Width of the segments (for BBox calculations in RTree)
    /// TODO Adjust usage of SHAPE_LINE_CHAIN to account for where we need a width and where not
    /// Alternatively, we could split the class into a LINE_CHAIN (no width) and SHAPE_LINE_CHAIN
    /// that derives from SHAPE as well that does have a width.  Not sure yet on the correct path.
    /// TODO Note that we also have SHAPE_SIMPLE which is a closed, filled SHAPE_LINE_CHAIN.
    int m_width;

    /// cached bounding box
    mutable BOX2I m_bbox;
};


#endif // __SHAPE_LINE_CHAIN