qgsbezierdata.h

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/***************************************************************************
    qgsbezierdata.h  -  Data structure for Poly-Bézier curve digitizing
    ---------------------
    begin                : December 2025
    copyright            : (C) 2025 by Loïc Bartoletti
                           Adapted from BezierEditing plugin work by Takayuki Mizutani
    email                : loic dot bartoletti at oslandia dot com
 ***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSBEZIERDATA_H
#define QGSBEZIERDATA_H
 
#include <memory>
 
#include "qgis_gui.h"
#include "qgspoint.h"
 
#define SIP_NO_FILE
 
class QgsNurbsCurve;


struct GUI_EXPORT QgsAnchorWithHandles
{
    QgsPoint anchor;      
    QgsPoint leftHandle;  
    QgsPoint rightHandle; 

    QgsAnchorWithHandles() = default;

    explicit QgsAnchorWithHandles( const QgsPoint &point )
      : anchor( point )
      , leftHandle( point )
      , rightHandle( point )
    {}

    QgsAnchorWithHandles( const QgsPoint &point, const QgsPoint &left, const QgsPoint &right )
      : anchor( point )
      , leftHandle( left )
      , rightHandle( right )
    {}
};

class GUI_EXPORT QgsBezierData
{
  public:
    QgsBezierData() = default;

    static constexpr int INTERPOLATION_POINTS = 32;

    void addAnchor( const QgsPoint &point );

    void moveAnchor( int index, const QgsPoint &point );

    void moveHandle( int index, const QgsPoint &point );

    void insertAnchor( int segmentIndex, const QgsPoint &point );

    void deleteAnchor( int index );

    void retractHandle( int index );

    void extendHandle( int index, const QgsPoint &point );

    int anchorCount() const { return mData.count(); }

    int handleCount() const { return mData.count() * 2; }

    QgsPoint anchor( int index ) const;

    QgsPoint handle( int index ) const;

    QVector<QgsPoint> anchors() const;

    QVector<QgsPoint> handles() const;

    const QgsAnchorWithHandles &anchorWithHandles( int index ) const;

    QgsPointSequence interpolateLine() const;

    std::unique_ptr<QgsNurbsCurve> asNurbsCurve( int degree = 3 ) const;

    static QgsBezierData fromPolyBezierControlPoints( const QVector<QgsPoint> &controlPoints, int degree = 3 );

    static QgsBezierData fromPolyBezierControlPoints( const QVector<QgsPointXY> &controlPoints, int degree = 3 );

    static void calculateSymmetricHandles( QVector<QgsPoint> &controlPoints, int anchorIndex, const QgsPoint &mousePosition );

    static void calculateSymmetricHandles( const QgsPoint &anchor, const QgsPoint &mousePosition, QgsPoint *handleFollow, QgsPoint *handleOpposite );

    void calculateSymmetricHandles( int anchorIndex, const QgsPoint &mousePosition );

    void clear();

    bool isEmpty() const { return mData.isEmpty(); }

    int findClosestAnchor( const QgsPoint &point, double tolerance ) const;

    int findClosestHandle( const QgsPoint &point, double tolerance ) const;

    int findClosestSegment( const QgsPoint &point, double tolerance ) const;
 
  private:
    QVector<QgsAnchorWithHandles> mData;              
    static const QgsAnchorWithHandles sInvalidAnchor; 
};

 
#endif // QGSBEZIERDATA_H