UT_HilbertSequence.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        UT_HilbertSequence.h (UT Library, C++)
 *
 * COMMENTS:    A class that generates a 2D Hilbert Curve within a given
 *              rectangle.
 */

#ifndef __UT_HILBERTSEQUENCE_H_INCLUDED__
#define __UT_HILBERTSEQUENCE_H_INCLUDED__

#include "UT_API.h"

class UT_API UT_HilbertCurve2D
{
public:
    UT_HilbertCurve2D(int level = 0);

    // Get the coordinates of a point on the Hilbert curve at the given
    // distance along the curve. Returns false if the distance exceeds the
    // curve length, as defined by its level.
    bool                 getPointFromDistance(int d, int &xp, int &yp) const;

    /// Retrieve the distance along the curve given coordinates of a point on
    /// the curve. If the coordinates are outside of the curve's bounding
    /// square, as defined by its level, the distance returned is -1.
    int                  getDistanceFromPoint(int xp, int yp) const;

    /// Advance the from the point at the given coordinates, to the next point
    /// along the curve and return those new coordinates. If the point is
    /// already at the end of the curve, this call returns false and the
    /// coordinates are left untouched.
    bool                 advancePointAlongCurve(int &xp, int &yp) const;

    int                  getLevel() const       { return myLevel; }
    int                  getSize() const        { return mySize; }
    int                  getLength() const      { return mySize * mySize; }
    
private:
    int                  myLevel;
    int                  mySize;
};

class UT_API UT_HilbertSequence2D
{
public:
    /// Initializes sequence data with the given parameters
    /// @param res_x @n Sequence resolution in x
    /// @param res_y @n Sequence resolution in y
    UT_HilbertSequence2D(int res_x = 0, int res_y = 0);

    class UT_API iterator
    {
    public:
        iterator();
        iterator(const UT_HilbertSequence2D &sequence);
        
        int              getDistance() const    { return myDistance; }
        int              getIndex() const       { return myIndex; }
        void             getCoord(int &x, int &y) const;
        
        void             rewind();
        void             advance();
        bool             atEnd() const;
        
        iterator        &operator++()           { advance(); return *this; }
        // No post increment as it is harmful
    protected:
    private:
        int              myResX, myResY;
        int              myDistance;
        int              myIndex;
        int              myCoordX, myCoordY;
        UT_HilbertCurve2D myCurve;
    };

    iterator             begin() const          { return iterator(*this); }

    int                  getXRes() const        { return myResX; }
    int                  getYRes() const        { return myResY; }
    
private:
    int                  myResX;
    int                  myResY;
};

#endif // __UT_HILBERTSEQUENCE_H_INCLUDED__