qwt_plot_magnifier.cpp

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/* -*- 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_plot.h"
#include "qwt_scale_div.h"
#include "qwt_plot_magnifier.h"

class QwtPlotMagnifier::PrivateData
{
public:
    PrivateData()
    {
        for ( int axis = 0; axis < QwtPlot::axisCnt; axis++ )
            isAxisEnabled[axis] = true;
    }

    bool isAxisEnabled[QwtPlot::axisCnt];
};

QwtPlotMagnifier::QwtPlotMagnifier( QWidget *canvas ):
    QwtMagnifier( canvas )
{
    d_data = new PrivateData();
}

QwtPlotMagnifier::~QwtPlotMagnifier()
{
    delete d_data;
}

void QwtPlotMagnifier::setAxisEnabled( int axis, bool on )
{
    if ( axis >= 0 && axis < QwtPlot::axisCnt )
        d_data->isAxisEnabled[axis] = on;
}

bool QwtPlotMagnifier::isAxisEnabled( int axis ) const
{
    if ( axis >= 0 && axis < QwtPlot::axisCnt )
        return d_data->isAxisEnabled[axis];

    return true;
}

QWidget *QwtPlotMagnifier::canvas()
{
    return parentWidget();
}

const QWidget *QwtPlotMagnifier::canvas() const
{
    return parentWidget();
}

QwtPlot *QwtPlotMagnifier::plot()
{
    QWidget *w = canvas();
    if ( w )
        w = w->parentWidget();

    return qobject_cast<QwtPlot *>( w );
}

const QwtPlot *QwtPlotMagnifier::plot() const
{
    const QWidget *w = canvas();
    if ( w )
        w = w->parentWidget();

    return qobject_cast<const QwtPlot *>( w );
}

void QwtPlotMagnifier::rescale( double factor )
{
    QwtPlot* plt = plot();
    if ( plt == NULL )
        return;

    factor = qAbs( factor );
    if ( factor == 1.0 || factor == 0.0 )
        return;

    bool doReplot = false;

    const bool autoReplot = plt->autoReplot();
    plt->setAutoReplot( false );

    for ( int axisId = 0; axisId < QwtPlot::axisCnt; axisId++ )
    {
        if ( isAxisEnabled( axisId ) )
        {
            const QwtScaleMap scaleMap = plt->canvasMap( axisId );

            double v1 = scaleMap.s1();
            double v2 = scaleMap.s2();

            if ( scaleMap.transformation() )
            {
                // the coordinate system of the paint device is always linear

                v1 = scaleMap.transform( v1 ); // scaleMap.p1()
                v2 = scaleMap.transform( v2 ); // scaleMap.p2()
            }

            const double center = 0.5 * ( v1 + v2 );
            const double width_2 = 0.5 * ( v2 - v1 ) * factor;

            v1 = center - width_2;
            v2 = center + width_2;

            if ( scaleMap.transformation() )
            {
                v1 = scaleMap.invTransform( v1 );
                v2 = scaleMap.invTransform( v2 );
            }

            plt->setAxisScale( axisId, v1, v2 );
            doReplot = true;
        }
    }

    plt->setAutoReplot( autoReplot );

    if ( doReplot )
        plt->replot();
}