path: root/basegfx/inc/basegfx/point/b2dhompoint.hxx

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#ifndef _BGFX_POINT_B2DHOMPOINT_HXX
#define _BGFX_POINT_B2DHOMPOINT_HXX

#ifndef _BGFX_POINT_B2DPOINT_HXX
#include <basegfx/point/b2dpoint.hxx>
#endif

namespace basegfx
{
    namespace point
    {
        /** Basic homogen Point class with two double values and one homogen factor

            This class provides access to homogen coordinates in 2D.
            For this purpose all the operators which need to do specific
            action due to their homogenity are implemented here.
            The only caveat are member methods which are declared as const
            but do change the content. These are documented for that reason.
            The class is designed to provide homogenous coordinates without
            direct access to the homogen part (mfW). This is also the reason
            for leaving out the [] operators which return references to members.

            @see B2DTuple
        */
        class B2DHomPoint
        {
        protected:
            /// This member contains the coordinate part of the point
            ::basegfx::tuple::B2DTuple                  maTuple;

            /// This Member holds the homogenous part of the point
            double                                      mfW;

            /** Test if this homogen point does have a homogenous part

                @return Returns sal_True if this point has no homogenous part
            */
            sal_Bool implIsHomogenized() const;

            /** Remove homogenous part of this Point

                This method does necessary calculations to remove
                the evtl. homogenous part of this Point. This may
                change all members.
            */
            void implHomogenize();

            /** Test and on demand remove homogenous part

                This method tests if this Point does have a homogenous part
                and then evtl. takes actions to remove that part.

                @attention Even when this method is const it may change all
                members of this instance. This is due to the fact that changing
                the homogenous part of a homogenous point does from a mathematical
                point of view not change the point at all.
            */
            void implTestAndHomogenize() const;

        public:
            /** Create a homogen point

                @param fVal
                This parameter is used to initialize the coordinate
                part of the Point. The homogenous part is initialized to 1.0.
            */
            B2DHomPoint(double fVal = 0.0)
            :   maTuple(fVal),
                mfW(1.0)
            {}

            /** Create a homogen point

                @param fX
                This parameter is used to initialize the X-coordinate
                of the Point. The homogenous part is initialized to 1.0.

                @param fY
                This parameter is used to initialize the Y-coordinate
                of the Point. The homogenous part is initialized to 1.0.
            */
            B2DHomPoint(double fX, double fY)
            :   maTuple(fX, fY),
                mfW(1.0)
            {}

            /** Create a copy of a 2D Point

                @param rVec
                The 2D point which will be copied. The homogenous part
                is initialized to 1.0.
            */
            B2DHomPoint(const B2DPoint& rVec)
            :   maTuple(rVec),
                mfW(1.0)
            {}

            /** Create a copy of a homogen point

                @param rVec
                The homogen point which will be copied. The homogenous part
                is copied, too.
            */
            B2DHomPoint(const B2DHomPoint& rVec)
            :   maTuple(rVec.maTuple.getX(), rVec.maTuple.getY()),
                mfW(rVec.mfW)
            {}

            ~B2DHomPoint()
            {}

            /** Get a 2D point from this homogenous point

                This method normalizes this homogen point if necessary and
                returns the corresponding 2D point for this homogen point.

                @attention Even when this method is const it may change all
                members of this instance.
            */
            B2DPoint getB2DPoint() const;

            /** Get X-coordinate

                This method normalizes this homogen point if necessary and
                returns the corresponding X-coordinate for this homogen point.

                @attention Even when this method is const it may change all
                members of this instance.
            */
            double getX() const;

            /** Get Y-coordinate

                This method normalizes this homogen point if necessary and
                returns the corresponding Y-coordinate for this homogen point.

                @attention Even when this method is const it may change all
                members of this instance.
            */
            double getY() const;

            /** Set X-coordinate of the homogen point.

                This method sets the X-coordinate of the homogen point. If
                the point does have a homogenous part this is taken into account.

                @param fX
                The to-be-set X-coordinate without homogenous part.
            */
            void setX(double fX);

            /** Set Y-coordinate of the homogen point.

                This method sets the Y-coordinate of the homogen point. If
                the point does have a homogenous part this is taken into account.

                @param fY
                The to-be-set Y-coordinate without homogenous part.
            */
            void setY(double fY);

            // operators
            //////////////////////////////////////////////////////////////////////

            B2DHomPoint& operator+=( const B2DHomPoint& rPnt );

            B2DHomPoint& operator-=( const B2DHomPoint& rPnt );

            B2DHomPoint& operator*=(double t);

            B2DHomPoint& operator*=( const matrix::B2DHomMatrix& rMat );

            B2DHomPoint& operator/=(double t);

            B2DHomPoint& operator-(void);

            sal_Bool operator==( const B2DHomPoint& rPnt ) const;

            sal_Bool operator!=( const B2DHomPoint& rPnt ) const;

            B2DHomPoint& operator=( const B2DHomPoint& rPnt );
        };

        // external operators
        //////////////////////////////////////////////////////////////////////////

        B2DHomPoint min(const B2DHomPoint& rVecA, const B2DHomPoint& rVecB);

        B2DHomPoint max(const B2DHomPoint& rVecA, const B2DHomPoint& rVecB);

        B2DHomPoint abs(const B2DHomPoint& rVec);

        B2DHomPoint interpolate(B2DHomPoint& rOld1, B2DHomPoint& rOld2, double t);

        B2DHomPoint average(B2DHomPoint& rOld1, B2DHomPoint& rOld2);

        B2DHomPoint average(B2DHomPoint& rOld1, B2DHomPoint& rOld2, B2DHomPoint& rOld3);

        B2DHomPoint operator+(const B2DHomPoint& rVecA, const B2DHomPoint& rVecB);

        B2DHomPoint operator-(const B2DHomPoint& rVecA, const B2DHomPoint& rVecB);

        B2DHomPoint operator*(const B2DHomPoint& rVec, double t);

        B2DHomPoint operator*(double t, const B2DHomPoint& rVec);

        B2DHomPoint operator*( const matrix::B2DHomMatrix& rMat, const B2DHomPoint& rPoint );

        B2DHomPoint operator/(const B2DHomPoint& rVec, double t);

        B2DHomPoint operator/(double t, const B2DHomPoint& rVec);
    } // end of namespace point
} // end of namespace basegfx

#endif // _BGFX_POINT_B2DHOMPOINT_HXX