b2dclipstate.cxx

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
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 *   except in compliance with the License. You may obtain a copy of
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 */
 
#include <basegfx/utils/b2dclipstate.hxx>
 
#include <basegfx/range/b2drange.hxx>
#include <basegfx/range/b2dpolyrange.hxx>
#include <basegfx/polygon/b2dpolygon.hxx>
#include <basegfx/polygon/b2dpolygontools.hxx>
#include <basegfx/polygon/b2dpolypolygon.hxx>
#include <basegfx/polygon/b2dpolypolygontools.hxx>
#include <basegfx/polygon/b2dpolypolygoncutter.hxx>
#include <utility>
 
 
namespace basegfx::utils
{
    class ImplB2DClipState
    {
    public:
        enum Operation {UNION, INTERSECT, XOR, SUBTRACT};
 
        ImplB2DClipState() :
            mePendingOps(UNION)
        {}
 
        explicit ImplB2DClipState( B2DPolyPolygon aPoly ) :
            maClipPoly(std::move(aPoly)),
            mePendingOps(UNION)
        {}
 
        bool isCleared() const
        {
            return !maClipPoly.count()
                && !maPendingPolygons.count()
                && !maPendingRanges.count();
        }
 
        bool isNullClipPoly() const
        {
            return maClipPoly.count() == 1
                && !maClipPoly.getB2DPolygon(0).count();
        }
 
        bool isNull() const
        {
            return !maPendingPolygons.count()
                && !maPendingRanges.count()
                && isNullClipPoly();
        }
 
        void makeNull()
        {
            maPendingPolygons.clear();
            maPendingRanges.clear();
            maClipPoly.clear();
            maClipPoly.append(B2DPolygon());
            mePendingOps = UNION;
        }
 
        bool operator==(const ImplB2DClipState& rRHS) const
        {
            return maPendingPolygons == rRHS.maPendingPolygons
                && maPendingRanges == rRHS.maPendingRanges
                && maClipPoly == rRHS.maClipPoly
                && mePendingOps == rRHS.mePendingOps;
        }
 
        void addRange(const B2DRange& rRange, Operation eOp)
        {
            if( rRange.isEmpty() )
                return;
 
            commitPendingPolygons();
            if( mePendingOps != eOp )
                commitPendingRanges();
 
            mePendingOps = eOp;
            maPendingRanges.appendElement(
                rRange,
                B2VectorOrientation::Positive);
        }
 
        void addPolyPolygon(const B2DPolyPolygon& aPoly, Operation eOp)
        {
            commitPendingRanges();
            if( mePendingOps != eOp )
                commitPendingPolygons();
 
            mePendingOps = eOp;
            maPendingPolygons.append(aPoly);
        }
 
        void unionRange(const B2DRange& rRange)
        {
            if( isCleared() )
                return;
 
            addRange(rRange,UNION);
        }
 
        void unionPolyPolygon(const B2DPolyPolygon& rPolyPoly)
        {
            if( isCleared() )
                return;
 
            addPolyPolygon(rPolyPoly,UNION);
        }
 
        void intersectRange(const B2DRange& rRange)
        {
            if( isNull() )
                return;
 
            addRange(rRange,INTERSECT);
        }
 
        void intersectPolyPolygon(const B2DPolyPolygon& rPolyPoly)
        {
            if( isNull() )
                return;
 
            addPolyPolygon(rPolyPoly,INTERSECT);
        }
 
        void subtractRange(const B2DRange& rRange )
        {
            if( isNull() )
                return;
 
            addRange(rRange,SUBTRACT);
        }
 
        void subtractPolyPolygon(const B2DPolyPolygon& rPolyPoly)
        {
            if( isNull() )
                return;
 
            addPolyPolygon(rPolyPoly,SUBTRACT);
        }
 
        void xorRange(const B2DRange& rRange)
        {
            addRange(rRange,XOR);
        }
 
        void xorPolyPolygon(const B2DPolyPolygon& rPolyPoly)
        {
            addPolyPolygon(rPolyPoly,XOR);
        }
 
        void transform(const basegfx::B2DHomMatrix& rTranslate)
        {
            maPendingRanges.transform(rTranslate);
            maPendingPolygons.transform(rTranslate);
            maClipPoly.transform(rTranslate);
        }
 
        B2DPolyPolygon const & getClipPoly() const
        {
            commitPendingRanges();
            commitPendingPolygons();
 
            return maClipPoly;
        }
 
    private:
        void commitPendingPolygons() const
        {
            if( !maPendingPolygons.count() )
                return;
 
            // assumption: maClipPoly has kept polygons prepared for
            // clipping; i.e. no neutral polygons & correct
            // orientation
            maPendingPolygons = utils::prepareForPolygonOperation(maPendingPolygons);
            const bool bIsEmpty=isNullClipPoly();
            const bool bIsCleared=!maClipPoly.count();
            switch(mePendingOps)
            {
                case UNION:
                    assert( !bIsCleared );
 
                    if( bIsEmpty )
                        maClipPoly = maPendingPolygons;
                    else
                        maClipPoly = utils::solvePolygonOperationOr(
                            maClipPoly,
                            maPendingPolygons);
                    break;
                case INTERSECT:
                    assert( !bIsEmpty );
 
                    if( bIsCleared )
                        maClipPoly = maPendingPolygons;
                    else
                        maClipPoly = utils::solvePolygonOperationAnd(
                            maClipPoly,
                            maPendingPolygons);
                    break;
                case XOR:
                    if( bIsEmpty )
                        maClipPoly = maPendingPolygons;
                    else if( bIsCleared )
                    {
                        // not representable, strictly speaking,
                        // using polygons with the common even/odd
                        // or nonzero winding number fill rule. If
                        // we'd want to represent it, fill rule
                        // would need to be "non-negative winding
                        // number" (and we then would return
                        // 'holes' here)
 
                        // going for an ugly hack meanwhile
                        maClipPoly = utils::solvePolygonOperationXor(
                            B2DPolyPolygon(
                                utils::createPolygonFromRect(B2DRange(-1E20,-1E20,1E20,1E20))),
                            maPendingPolygons);
                    }
                    else
                        maClipPoly = utils::solvePolygonOperationXor(
                            maClipPoly,
                            maPendingPolygons);
                    break;
                case SUBTRACT:
                    assert( !bIsEmpty );
 
                    // first union all pending ones, subtract en bloc then
                    maPendingPolygons = solveCrossovers(maPendingPolygons);
                    maPendingPolygons = stripNeutralPolygons(maPendingPolygons);
                    maPendingPolygons = stripDispensablePolygons(maPendingPolygons);
 
                    if( bIsCleared )
                    {
                        // not representable, strictly speaking,
                        // using polygons with the common even/odd
                        // or nonzero winding number fill rule. If
                        // we'd want to represent it, fill rule
                        // would need to be "non-negative winding
                        // number" (and we then would return
                        // 'holes' here)
 
                        // going for an ugly hack meanwhile
                        maClipPoly = utils::solvePolygonOperationDiff(
                            B2DPolyPolygon(
                                utils::createPolygonFromRect(B2DRange(-1E20,-1E20,1E20,1E20))),
                            maPendingPolygons);
                    }
                    else
                        maClipPoly = utils::solvePolygonOperationDiff(
                            maClipPoly,
                            maPendingPolygons);
                    break;
            }
 
            maPendingPolygons.clear();
            mePendingOps = UNION;
        }
 
        void commitPendingRanges() const
        {
            if( !maPendingRanges.count() )
                return;
 
            // use the specialized range clipper for the win
            B2DPolyPolygon aCollectedRanges;
            const bool bIsEmpty=isNullClipPoly();
            const bool bIsCleared=!maClipPoly.count();
            switch(mePendingOps)
            {
                case UNION:
                    assert( !bIsCleared );
 
                    aCollectedRanges = maPendingRanges.solveCrossovers();
                    aCollectedRanges = stripNeutralPolygons(aCollectedRanges);
                    aCollectedRanges = stripDispensablePolygons(aCollectedRanges);
                    if( bIsEmpty )
                        maClipPoly = aCollectedRanges;
                    else
                        maClipPoly = utils::solvePolygonOperationOr(
                            maClipPoly,
                            aCollectedRanges);
                    break;
                case INTERSECT:
                    assert( !bIsEmpty );
 
                    aCollectedRanges = maPendingRanges.solveCrossovers();
                    aCollectedRanges = stripNeutralPolygons(aCollectedRanges);
                    if( maPendingRanges.count() > 1 )
                        aCollectedRanges = stripDispensablePolygons(aCollectedRanges, true);
 
                    if( bIsCleared )
                        maClipPoly = aCollectedRanges;
                    else
                        maClipPoly = utils::solvePolygonOperationAnd(
                            maClipPoly,
                            aCollectedRanges);
                    break;
                case XOR:
                    aCollectedRanges = maPendingRanges.solveCrossovers();
                    aCollectedRanges = stripNeutralPolygons(aCollectedRanges);
                    aCollectedRanges = correctOrientations(aCollectedRanges);
 
                    if( bIsEmpty )
                        maClipPoly = aCollectedRanges;
                    else if( bIsCleared )
                    {
                        // not representable, strictly speaking,
                        // using polygons with the common even/odd
                        // or nonzero winding number fill rule. If
                        // we'd want to represent it, fill rule
                        // would need to be "non-negative winding
                        // number" (and we then would return
                        // 'holes' here)
 
                        // going for an ugly hack meanwhile
                        maClipPoly = utils::solvePolygonOperationXor(
                            B2DPolyPolygon(
                                utils::createPolygonFromRect(B2DRange(-1E20,-1E20,1E20,1E20))),
                            aCollectedRanges);
                    }
                    else
                        maClipPoly = utils::solvePolygonOperationXor(
                            maClipPoly,
                            aCollectedRanges);
                    break;
                case SUBTRACT:
                    assert( !bIsEmpty );
 
                    // first union all pending ranges, subtract en bloc then
                    aCollectedRanges = maPendingRanges.solveCrossovers();
                    aCollectedRanges = stripNeutralPolygons(aCollectedRanges);
                    aCollectedRanges = stripDispensablePolygons(aCollectedRanges);
 
                    if( bIsCleared )
                    {
                        // not representable, strictly speaking,
                        // using polygons with the common even/odd
                        // or nonzero winding number fill rule. If
                        // we'd want to represent it, fill rule
                        // would need to be "non-negative winding
                        // number" (and we then would return
                        // 'holes' here)
 
                        // going for an ugly hack meanwhile
                        maClipPoly = utils::solvePolygonOperationDiff(
                            B2DPolyPolygon(
                                utils::createPolygonFromRect(B2DRange(-1E20,-1E20,1E20,1E20))),
                            aCollectedRanges);
                    }
                    else
                        maClipPoly = utils::solvePolygonOperationDiff(
                            maClipPoly,
                            aCollectedRanges);
                    break;
            }
 
            maPendingRanges.clear();
            mePendingOps = UNION;
        }
 
        mutable B2DPolyPolygon maPendingPolygons;
        mutable B2DPolyRange   maPendingRanges;
        mutable B2DPolyPolygon maClipPoly;
        mutable Operation      mePendingOps;
    };
 
    B2DClipState::B2DClipState() = default;
 
    B2DClipState::~B2DClipState() = default;
 
    B2DClipState::B2DClipState( const B2DClipState& ) = default;
 
    B2DClipState::B2DClipState( B2DClipState&& ) = default;
 
    B2DClipState::B2DClipState( const B2DPolyPolygon& rPolyPoly ) :
        mpImpl( ImplB2DClipState(rPolyPoly) )
    {}
 
    B2DClipState& B2DClipState::operator=( const B2DClipState& ) = default;
 
    B2DClipState& B2DClipState::operator=( B2DClipState&& ) = default;
 
    void B2DClipState::makeNull()
    {
        mpImpl->makeNull();
    }
 
    bool B2DClipState::isCleared() const
    {
        return mpImpl->isCleared();
    }
 
    bool B2DClipState::operator==(const B2DClipState& rRHS) const
    {
        if(mpImpl.same_object(rRHS.mpImpl))
            return true;
 
        return ((*mpImpl) == (*rRHS.mpImpl));
    }
 
    bool B2DClipState::operator!=(const B2DClipState& rRHS) const
    {
        return !(*this == rRHS);
    }
 
    void B2DClipState::unionRange(const B2DRange& rRange)
    {
        mpImpl->unionRange(rRange);
    }
 
    void B2DClipState::unionPolyPolygon(const B2DPolyPolygon& rPolyPoly)
    {
        mpImpl->unionPolyPolygon(rPolyPoly);
    }
 
    void B2DClipState::intersectRange(const B2DRange& rRange)
    {
        mpImpl->intersectRange(rRange);
    }
 
    void B2DClipState::intersectPolyPolygon(const B2DPolyPolygon& rPolyPoly)
    {
        mpImpl->intersectPolyPolygon(rPolyPoly);
    }
 
    void B2DClipState::subtractRange(const B2DRange& rRange)
    {
        mpImpl->subtractRange(rRange);
    }
 
    void B2DClipState::subtractPolyPolygon(const B2DPolyPolygon& rPolyPoly)
    {
        mpImpl->subtractPolyPolygon(rPolyPoly);
    }
 
    void B2DClipState::xorRange(const B2DRange& rRange)
    {
        mpImpl->xorRange(rRange);
    }
 
    void B2DClipState::xorPolyPolygon(const B2DPolyPolygon& rPolyPoly)
    {
        mpImpl->xorPolyPolygon(rPolyPoly);
    }
 
    B2DPolyPolygon const & B2DClipState::getClipPoly() const
    {
        return mpImpl->getClipPoly();
    }
 
    void B2DClipState::transform(const basegfx::B2DHomMatrix& rTranslate)
    {
        return mpImpl->transform(rTranslate);
    }
 
 
} // end of namespace
 
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