/* -*- 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_scale_map.h"
#include <qrect.h>
#include <qalgorithms.h>
#include <qmath.h>
#include <qdebug.h>

#if QT_VERSION < 0x040601
#define qExp(x) ::exp(x)
#endif

QT_STATIC_CONST_IMPL double QwtScaleMap::LogMin = 1.0e-150;
QT_STATIC_CONST_IMPL double QwtScaleMap::LogMax = 1.0e150;

//! Constructor for a linear transformation
QwtScaleTransformation::QwtScaleTransformation( Type type ):
    d_type( type )
{
}

//! Destructor
QwtScaleTransformation::~QwtScaleTransformation()
{
}

//! Create a clone of the transformation
QwtScaleTransformation *QwtScaleTransformation::copy() const
{
    return new QwtScaleTransformation( d_type );
}

/*!
  \brief Transform a value between 2 linear intervals

  \param s value related to the interval [s1, s2]
  \param s1 first border of scale interval
  \param s2 second border of scale interval
  \param p1 first border of target interval
  \param p2 second border of target interval
  \return
  <dl>
  <dt>linear mapping:<dd>p1 + (p2 - p1) / (s2 - s1) * (s - s1)</dd>
  </dl>
  <dl>
  <dt>log10 mapping: <dd>p1 + (p2 - p1) / log(s2 / s1) * log(s / s1)</dd>
  </dl>
*/

double QwtScaleTransformation::xForm(
    double s, double s1, double s2, double p1, double p2 ) const
{
    if ( d_type == Log10 )
        return p1 + ( p2 - p1 ) / log( s2 / s1 ) * log( s / s1 );
    else
        return p1 + ( p2 - p1 ) / ( s2 - s1 ) * ( s - s1 );
}

/*!
  \brief Transform a value from a linear to a logarithmic interval

  \param p value related to the linear interval [p1, p2]
  \param p1 first border of linear interval
  \param p2 second border of linear interval
  \param s1 first border of logarithmic interval
  \param s2 second border of logarithmic interval
  \return
  <dl>
  <dt>exp((p - p1) / (p2 - p1) * log(s2 / s1)) * s1;
  </dl>
*/

double QwtScaleTransformation::invXForm( double p, double p1, double p2,
    double s1, double s2 ) const
{
    if ( d_type == Log10 )
        return qExp( ( p - p1 ) / ( p2 - p1 ) * log( s2 / s1 ) ) * s1;
    else
        return s1 + ( s2 - s1 ) / ( p2 - p1 ) * ( p - p1 );
}

/*!
  \brief Constructor

  The scale and paint device intervals are both set to [0,1].
*/
QwtScaleMap::QwtScaleMap():
    d_s1( 0.0 ),
    d_s2( 1.0 ),
    d_p1( 0.0 ),
    d_p2( 1.0 ),
    d_cnv( 1.0 )
{
    d_transformation = new QwtScaleTransformation(
        QwtScaleTransformation::Linear );
}

//! Copy constructor
QwtScaleMap::QwtScaleMap( const QwtScaleMap& other ):
    d_s1( other.d_s1 ),
    d_s2( other.d_s2 ),
    d_p1( other.d_p1 ),
    d_p2( other.d_p2 ),
    d_cnv( other.d_cnv )
{
    d_transformation = other.d_transformation->copy();
}

/*!
  Destructor
*/
QwtScaleMap::~QwtScaleMap()
{
    delete d_transformation;
}

//! Assignment operator
QwtScaleMap &QwtScaleMap::operator=( const QwtScaleMap & other )
{
    d_s1 = other.d_s1;
    d_s2 = other.d_s2;
    d_p1 = other.d_p1;
    d_p2 = other.d_p2;
    d_cnv = other.d_cnv;

    delete d_transformation;
    d_transformation = other.d_transformation->copy();

    return *this;
}

/*!
   Initialize the map with a transformation
*/
void QwtScaleMap::setTransformation(
    QwtScaleTransformation *transformation )
{
    if ( transformation == NULL )
        return;

    if ( transformation != d_transformation )
    {
        delete d_transformation;
        d_transformation = transformation;
    }

    setScaleInterval( d_s1, d_s2 );
}

//! Get the transformation
const QwtScaleTransformation *QwtScaleMap::transformation() const
{
    return d_transformation;
}

/*!
  \brief Specify the borders of the scale interval
  \param s1 first border
  \param s2 second border
  \warning logarithmic scales might be aligned to [LogMin, LogMax]
*/
void QwtScaleMap::setScaleInterval( double s1, double s2 )
{
    if ( d_transformation->type() == QwtScaleTransformation::Log10 )
    {
        if ( s1 < LogMin )
            s1 = LogMin;
        else if ( s1 > LogMax )
            s1 = LogMax;

        if ( s2 < LogMin )
            s2 = LogMin;
        else if ( s2 > LogMax )
            s2 = LogMax;
    }

    d_s1 = s1;
    d_s2 = s2;

    if ( d_transformation->type() != QwtScaleTransformation::Other )
        newFactor();
}

/*!
  \brief Specify the borders of the paint device interval
  \param p1 first border
  \param p2 second border
*/
void QwtScaleMap::setPaintInterval( double p1, double p2 )
{
    d_p1 = p1;
    d_p2 = p2;

    if ( d_transformation->type() != QwtScaleTransformation::Other )
        newFactor();
}

/*!
  \brief Re-calculate the conversion factor.
*/
void QwtScaleMap::newFactor()
{
    d_cnv = 0.0;

    switch ( d_transformation->type() )
    {
        case QwtScaleTransformation::Linear:
            if ( d_s2 != d_s1 )
                d_cnv = ( d_p2 - d_p1 ) / ( d_s2 - d_s1 );
            break;
        case QwtScaleTransformation::Log10:
            if ( d_s1 != 0 )
                d_cnv = ( d_p2 - d_p1 ) / log( d_s2 / d_s1 );
            break;
        default:;
    }
}

/*!
   Transform a rectangle

   \param xMap X map
   \param yMap Y map
   \param rect Rectangle in scale coordinates
   \return Rectangle in paint coordinates

   \sa invTransform()
*/
QRectF QwtScaleMap::transform( const QwtScaleMap &xMap,
    const QwtScaleMap &yMap, const QRectF &rect )
{
    double x1 = xMap.transform( rect.left() );
    double x2 = xMap.transform( rect.right() );
    double y1 = yMap.transform( rect.top() );
    double y2 = yMap.transform( rect.bottom() );

    if ( x2 < x1 )
        qSwap( x1, x2 );
    if ( y2 < y1 )
        qSwap( y1, y2 );

    if ( qwtFuzzyCompare( x1, 0.0, x2 - x1 ) == 0 )
        x1 = 0.0;
    if ( qwtFuzzyCompare( x2, 0.0, x2 - x1 ) == 0 )
        x2 = 0.0;
    if ( qwtFuzzyCompare( y1, 0.0, y2 - y1 ) == 0 )
        y1 = 0.0;
    if ( qwtFuzzyCompare( y2, 0.0, y2 - y1 ) == 0 )
        y2 = 0.0;

    return QRectF( x1, y1, x2 - x1 + 1, y2 - y1 + 1 );
}

/*!
   Transform a rectangle from paint to scale coordinates

   \param xMap X map
   \param yMap Y map
   \param rect Rectangle in paint coordinates
   \return Rectangle in scale coordinates
   \sa transform()
*/
QRectF QwtScaleMap::invTransform( const QwtScaleMap &xMap,
    const QwtScaleMap &yMap, const QRectF &rect )
{
    const double x1 = xMap.invTransform( rect.left() );
    const double x2 = xMap.invTransform( rect.right() - 1 );
    const double y1 = yMap.invTransform( rect.top() );
    const double y2 = yMap.invTransform( rect.bottom() - 1 );

    const QRectF r( x1, y1, x2 - x1, y2 - y1 );
    return r.normalized();
}

#ifndef QT_NO_DEBUG_STREAM

QDebug operator<<( QDebug debug, const QwtScaleMap &map )
{
    debug.nospace() << "QwtScaleMap("
        << static_cast<int>( map.transformation()->type() )
        << ", s:" << map.s1() << "->" << map.s2()
        << ", p:" << map.p1() << "->" << map.p2()
        << ")";

    return debug.space();
}

#endif