qwt_clipper.cpp

/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include "qwt_clipper.h"
#include "qwt_point_polar.h"
#include <qrect.h>
#include <string.h>
#include <stdlib.h>

#if QT_VERSION < 0x040601
#define qAtan(x) ::atan(x)
#endif

namespace QwtClip
{
    // some templates used for inlining
    template <class Point, typename T> class LeftEdge;
    template <class Point, typename T> class RightEdge;
    template <class Point, typename T> class TopEdge;
    template <class Point, typename T> class BottomEdge;

    template <class Point> class PointBuffer;
}

template <class Point, typename Value>
class QwtClip::LeftEdge
{
public:
    inline LeftEdge( Value x1, Value, Value, Value ):
        d_x1( x1 )
    {
    }

    inline bool isInside( const Point &p  ) const
    {
        return p.x() >= d_x1;
    }

    inline Point intersection( const Point &p1, const Point &p2 ) const
    {
        double dy = ( p1.y() - p2.y() ) / double( p1.x() - p2.x() );
        return Point( d_x1, static_cast< Value >( p2.y() + ( d_x1 - p2.x() ) * dy ) );
    }
private:
    const Value d_x1;
};

template <class Point, typename Value>
class QwtClip::RightEdge
{
public:
    inline RightEdge( Value, Value x2, Value, Value ):
        d_x2( x2 )
    {
    }

    inline bool isInside( const Point &p  ) const
    {
        return p.x() <= d_x2;
    }

    inline Point intersection( const Point &p1, const Point &p2 ) const
    {
        double dy = ( p1.y() - p2.y() ) / double( p1.x() - p2.x() );
        return Point( d_x2, static_cast<Value>( p2.y() + ( d_x2 - p2.x() ) * dy ) );
    }

private:
    const Value d_x2;
};

template <class Point, typename Value>
class QwtClip::TopEdge
{
public:
    inline TopEdge( Value, Value, Value y1, Value ):
        d_y1( y1 )
    {
    }

    inline bool isInside( const Point &p  ) const
    {
        return p.y() >= d_y1;
    }

    inline Point intersection( const Point &p1, const Point &p2 ) const
    {
        double dx = ( p1.x() - p2.x() ) / double( p1.y() - p2.y() );
        return Point( static_cast<Value>( p2.x() + ( d_y1 - p2.y() ) * dx ), d_y1 );
    }

private:
    const Value d_y1;
};

template <class Point, typename Value>
class QwtClip::BottomEdge
{
public:
    inline BottomEdge( Value, Value, Value, Value y2 ):
        d_y2( y2 )
    {
    }