QwtPlotMagnifier Class Reference

QwtPlotMagnifier provides zooming, by magnifying in steps. More...

#include <qwt_plot_magnifier.h>

Inheritance diagram for QwtPlotMagnifier:

Collaboration diagram for QwtPlotMagnifier:

List of all members.

Classes
class	PrivateData
Public Member Functions
	QwtPlotMagnifier (QwtPlotCanvas *)
virtual	~QwtPlotMagnifier ()
	Destructor.
void	setAxisEnabled (int axis, bool on)
	En/Disable an axis.
bool	isAxisEnabled (int axis) const
QwtPlotCanvas *	canvas ()
	Return observed plot canvas.
const QwtPlotCanvas *	canvas () const
	Return Observed plot canvas.
QwtPlot *	plot ()
	Return plot widget, containing the observed plot canvas.
const QwtPlot *	plot () const
	Return plot widget, containing the observed plot canvas.
Protected Member Functions
virtual void	rescale (double factor)

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Detailed Description

QwtPlotMagnifier provides zooming, by magnifying in steps.

Using QwtPlotMagnifier a plot can be zoomed in/out in steps using keys, the mouse wheel or moving a mouse button in vertical direction.

Together with QwtPlotZoomer and QwtPlotPanner it is possible to implement individual and powerful navigation of the plot canvas.

See also:

QwtPlotZoomer, QwtPlotPanner, QwtPlot

Definition at line 30 of file qwt_plot_magnifier.h.

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Constructor & Destructor Documentation

QwtPlotMagnifier::QwtPlotMagnifier

(

QwtPlotCanvas *

canvas )

[explicit]

Constructor

Parameters:

canvas

Plot canvas to be magnified

Definition at line 35 of file qwt_plot_magnifier.cpp.

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

QwtPlotMagnifier::~QwtPlotMagnifier

(

)

[virtual]

Destructor.

Definition at line 42 of file qwt_plot_magnifier.cpp.

{
    delete d_data;
}

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Member Function Documentation

QwtPlotCanvas * QwtPlotMagnifier::canvas

(

)

Return observed plot canvas.

Definition at line 81 of file qwt_plot_magnifier.cpp.

Referenced by plot().

{
    QObject *w = parent();
    if ( w && w->inherits("QwtPlotCanvas") )
        return (QwtPlotCanvas *)w;

    return NULL;
}

const QwtPlotCanvas * QwtPlotMagnifier::canvas

(

)

const

Return Observed plot canvas.

Definition at line 91 of file qwt_plot_magnifier.cpp.

{
    return ((QwtPlotMagnifier *)this)->canvas();
}

bool QwtPlotMagnifier::isAxisEnabled

(

int

axis )

const

Test if an axis is enabled

Parameters:

axis	Axis, see QwtPlot::Axis

Returns:

True, if the axis is enabled

See also:

setAxisEnabled()

Definition at line 72 of file qwt_plot_magnifier.cpp.

References QwtPlot::axisCnt, and QwtPlotMagnifier::PrivateData::isAxisEnabled.

Referenced by rescale().

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

    return true;
}

QwtPlot * QwtPlotMagnifier::plot

(

)

Return plot widget, containing the observed plot canvas.

Definition at line 97 of file qwt_plot_magnifier.cpp.

References canvas().

Referenced by rescale().

{
    QObject *w = canvas();
    if ( w )
    {
        w = w->parent();
        if ( w && w->inherits("QwtPlot") )
            return (QwtPlot *)w;
    }

    return NULL;
}

const QwtPlot * QwtPlotMagnifier::plot

(

)

const

Return plot widget, containing the observed plot canvas.

Definition at line 111 of file qwt_plot_magnifier.cpp.

{
    return ((QwtPlotMagnifier *)this)->plot();
}

void QwtPlotMagnifier::rescale

(

double

factor )

[protected, virtual]

Zoom in/out the axes scales

Parameters:

factor

A value < 1.0 zooms in, a value > 1.0 zooms out.

Implements QwtMagnifier.

Definition at line 120 of file qwt_plot_magnifier.cpp.

References QwtPlot::autoReplot(), QwtPlot::axisCnt, QwtPlot::axisScaleDiv(), isAxisEnabled(), QwtScaleDiv::isValid(), QwtScaleDiv::lowerBound(), plot(), qwtAbs, QwtScaleDiv::range(), QwtPlot::replot(), QwtPlot::setAutoReplot(), and QwtPlot::setAxisScale().

{
    factor = qwtAbs(factor);
    if ( factor == 1.0 || factor == 0.0 )
        return;

    bool doReplot = false;
    QwtPlot* plt = plot();

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

    for ( int axisId = 0; axisId < QwtPlot::axisCnt; axisId++ )
    {
        const QwtScaleDiv *scaleDiv = plt->axisScaleDiv(axisId);
        if ( isAxisEnabled(axisId) && scaleDiv->isValid() )
        {
            const double center =
                scaleDiv->lowerBound() + scaleDiv->range() / 2;
            const double width_2 = scaleDiv->range() / 2 * factor;

            plt->setAxisScale(axisId, center - width_2, center + width_2);
            doReplot = true;
        }
    }

    plt->setAutoReplot(autoReplot);

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

void QwtPlotMagnifier::setAxisEnabled	(	int	axis,
		bool	on
	)

En/Disable an axis.

Axes that are enabled will be synchronized to the result of panning. All other axes will remain unchanged.

Parameters:

axis	Axis, see QwtPlot::Axis
on	On/Off

See also:

isAxisEnabled()

Definition at line 58 of file qwt_plot_magnifier.cpp.

References QwtPlot::axisCnt, and QwtPlotMagnifier::PrivateData::isAxisEnabled.

{
    if ( axis >= 0 && axis < QwtPlot::axisCnt )
        d_data->isAxisEnabled[axis] = on;
}

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The documentation for this class was generated from the following files:

• qwt_plot_magnifier.h
• qwt_plot_magnifier.cpp