Base class for items on the plot canvas. More...

#include <qwt_plot_item.h>

Inheritance diagram for QwtPlotItem:

Collaboration diagram for QwtPlotItem:

Classes
class	PrivateData
Public Types
enum	RttiValues { Rtti_PlotItem = 0, Rtti_PlotGrid, Rtti_PlotScale, Rtti_PlotMarker, Rtti_PlotCurve, Rtti_PlotHistogram, Rtti_PlotSpectrogram, Rtti_PlotSVG, Rtti_PlotUserItem = 1000 }
	Runtime type information. More...
enum	ItemAttribute { Legend = 1, AutoScale = 2 }
Public Member Functions
	QwtPlotItem (const QwtText &title=QwtText())
virtual	~QwtPlotItem ()
	Destroy the QwtPlotItem.
void	attach (QwtPlot *plot)
	Attach the item to a plot.
void	detach ()
	This method detaches a QwtPlotItem from any QwtPlot it has been associated with.
QwtPlot *	plot () const
	Return attached plot.
void	setTitle (const QString &title)
void	setTitle (const QwtText &title)
const QwtText &	title () const
virtual int	rtti () const
void	setItemAttribute (ItemAttribute, bool on=true)
bool	testItemAttribute (ItemAttribute) const
double	z () const
void	setZ (double z)
	Set the z value.
void	show ()
	Show the item.
void	hide ()
	Hide the item.
virtual void	setVisible (bool)
bool	isVisible () const
void	setAxis (int xAxis, int yAxis)
void	setXAxis (int axis)
int	xAxis () const
	Return xAxis.
void	setYAxis (int axis)
int	yAxis () const
	Return yAxis.
virtual void	itemChanged ()
virtual void	draw (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &canvasRect) const =0
	Draw the item.
virtual QwtDoubleRect	boundingRect () const
virtual void	updateLegend (QwtLegend *) const
	Update the widget that represents the item on the legend.
virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
	Update the item to changes of the axes scale division.
virtual QWidget *	legendItem () const
	Allocate the widget that represents the item on the legend.
QwtDoubleRect	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding scale rect of 2 maps.
QRect	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding paint rect of 2 maps.
QRect	transform (const QwtScaleMap &, const QwtScaleMap &, const QwtDoubleRect &) const
QwtDoubleRect	invTransform (const QwtScaleMap &, const QwtScaleMap &, const QRect &) const

Detailed Description

Base class for items on the plot canvas.

A plot item is "something", that can be painted on the plot canvas, or only affects the scales of the plot widget. They can be categorized as:

Representator
A "Representator" is an item that represents some sort of data on the plot canvas. The different representator classes are organized according to the characteristics of the data:
- QwtPlotMarker Represents a point or a horizontal/vertical coordinate
- QwtPlotCurve Represents a series of points
- QwtPlotSpectrogram ( QwtPlotRasterItem ) Represents raster data
- ...

Decorators
A "Decorator" is an item, that displays additional information, that is not related to any data:
- QwtPlotGrid
- QwtPlotScaleItem
- QwtPlotSvgItem
- ...

Depending on the QwtPlotItem::ItemAttribute flags, an item is included into autoscaling or has an entry on the legnd.

Before misusing the existing item classes it might be better to implement a new type of plot item ( don't implement a watermark as spectrogram ). Deriving a new type of QwtPlotItem primarily means to implement the YourPlotItem::draw() method.

See also:: The cpuplot example shows the implementation of additional plot items.

Definition at line 65 of file qwt_plot_item.h.

Member Enumeration Documentation

enum QwtPlotItem::ItemAttribute

Plot Item Attributes

Legend
The item is represented on the legend.
AutoScale
The boundingRect() of the item is included in the autoscaling calculation.

See also:: setItemAttribute(), testItemAttribute()

Enumerator:

Legend
AutoScale

Definition at line 100 of file qwt_plot_item.h.

    {
        Legend = 1,
        AutoScale = 2
    };

enum QwtPlotItem::RttiValues

Runtime type information.

RttiValues is used to cast plot items, without having to enable runtime type information of the compiler.

Enumerator:

Rtti_PlotItem
Rtti_PlotGrid
Rtti_PlotScale
Rtti_PlotMarker
Rtti_PlotCurve
Rtti_PlotHistogram
Rtti_PlotSpectrogram
Rtti_PlotSVG
Rtti_PlotUserItem

Definition at line 74 of file qwt_plot_item.h.

    { 
        Rtti_PlotItem = 0,

        Rtti_PlotGrid,
        Rtti_PlotScale,
        Rtti_PlotMarker,
        Rtti_PlotCurve,
        Rtti_PlotHistogram,
        Rtti_PlotSpectrogram,
        Rtti_PlotSVG,

        Rtti_PlotUserItem = 1000
    };

Constructor & Destructor Documentation

QwtPlotItem::QwtPlotItem ( const QwtText & title = QwtText() ) [explicit]

Constructor

Parameters:

title Title of the item

Definition at line 51 of file qwt_plot_item.cpp.

References title(), and QwtPlotItem::PrivateData::title.

{
    d_data = new PrivateData;
    d_data->title = title;
}

QwtPlotItem::~QwtPlotItem ( ) [virtual]

Destroy the QwtPlotItem.

Definition at line 58 of file qwt_plot_item.cpp.

References attach().

{
    attach(NULL);
    delete d_data;
}

Member Function Documentation

void QwtPlotItem::attach ( QwtPlot * plot )

Attach the item to a plot.

This method will attach a QwtPlotItem to the QwtPlot argument. It will first detach the QwtPlotItem from any plot from a previous call to attach (if necessary). If a NULL argument is passed, it will detach from any QwtPlot it was attached to.

Parameters:

plot	Plot widget

See also:: QwtPlotItem::detach()

Definition at line 75 of file qwt_plot_item.cpp.

References QwtPlot::autoReplot(), QwtLegend::find(), itemChanged(), QwtPlot::legend(), legendItem(), plot(), and QwtPlotItem::PrivateData::plot.

Referenced by QwtPlotDict::detachItems(), QmitkHistogramWidget::InitializeMarker(), QmitkPlotWidget::InsertCurve(), QmitkHistogramWidget::QmitkHistogramWidget(), QmitkHistogramWidget::SetHistogram(), and ~QwtPlotItem().

{
    if ( plot == d_data->plot )
        return;

    // remove the item from the previous plot

    if ( d_data->plot )
    {
        if ( d_data->plot->legend() )
        {
            QWidget *legendItem = d_data->plot->legend()->find(this);
            if ( legendItem )
                delete legendItem; 
        }

        d_data->plot->attachItem(this, false);

        if ( d_data->plot->autoReplot() )
            d_data->plot->update();
    }

    d_data->plot = plot;

    if ( d_data->plot )
    {
        // insert the item into the current plot

        d_data->plot->attachItem(this, true);
        itemChanged();
    }
}

QwtDoubleRect QwtPlotItem::boundingRect ( ) const [virtual]

Returns:: An invalid bounding rect: QwtDoubleRect(1.0, 1.0, -2.0, -2.0)

Reimplemented in QmitkHistogram, QwtPlotCurve, QwtPlotMarker, QwtPlotSpectrogram, and QwtPlotSvgItem.

Definition at line 392 of file qwt_plot_item.cpp.

Referenced by QwtPlotRasterItem::draw(), QwtPlotCurve::maxXValue(), QwtPlotCurve::maxYValue(), QwtPlotCurve::minXValue(), QwtPlotCurve::minYValue(), and QwtPlot::updateAxes().

{
    return QwtDoubleRect(1.0, 1.0, -2.0, -2.0); // invalid
}

void QwtPlotItem::detach ( ) [inline]

This method detaches a QwtPlotItem from any QwtPlot it has been associated with.

detach() is equivalent to calling attach( NULL )

See also:: attach( QwtPlot* plot )

Definition at line 126 of file qwt_plot_item.h.

{ attach(NULL); }

virtual void QwtPlotItem::draw	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRect &	canvasRect
	)		const `[pure virtual]`

Draw the item.

Parameters:

painter	Painter
xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.
canvasRect	Contents rect of the canvas in painter coordinates

Implemented in QmitkHistogram, QwtPlotCurve, QwtPlotGrid, QwtPlotMarker, QwtPlotRasterItem, QwtPlotScaleItem, QwtPlotSpectrogram, and QwtPlotSvgItem.

Referenced by QwtPlot::drawItems().

void QwtPlotItem::hide ( )

Hide the item.

Definition at line 276 of file qwt_plot_item.cpp.

References setVisible().

{
    setVisible(false);
}

QwtDoubleRect QwtPlotItem::invTransform	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRect &	rect
	)		const

Transform a rectangle from paint to scale coordinates

Parameters:

xMap	X map
yMap	Y map
rect	Rectangle in paint coordinates

Returns:: Rectangle in scale coordinates

See also:: transform()

Definition at line 553 of file qwt_plot_item.cpp.

References QwtScaleMap::invTransform(), and QwtDoubleRect::normalized().

Referenced by QwtPlotSvgItem::draw(), QwtPlotSpectrogram::draw(), and QwtPlotRasterItem::draw().

{
    const double x1 = xMap.invTransform(rect.left());
    const double x2 = xMap.invTransform(rect.right());
    const double y1 = yMap.invTransform(rect.top());
    const double y2 = yMap.invTransform(rect.bottom());
        
    const QwtDoubleRect r(x1, y1, x2 - x1, y2 - y1);

    return r.normalized();
}

bool QwtPlotItem::isVisible ( ) const

Returns:: true if visible

See also:: setVisible(), show(), hide()

Definition at line 300 of file qwt_plot_item.cpp.

References QwtPlotItem::PrivateData::isVisible.

Referenced by QwtPlot::drawItems().

{ 
    return d_data->isVisible; 
}

void QwtPlotItem::itemChanged ( ) [virtual]

Update the legend and call QwtPlot::autoRefresh for the parent plot.

See also:: updateLegend()

Definition at line 311 of file qwt_plot_item.cpp.

References QwtPlot::autoRefresh(), QwtPlot::legend(), QwtPlotItem::PrivateData::plot, and updateLegend().

{
    if ( d_data->plot )
    {
        if ( d_data->plot->legend() )
            updateLegend(d_data->plot->legend());

        d_data->plot->autoRefresh();
    }
}

QWidget * QwtPlotItem::legendItem ( ) const [virtual]

Allocate the widget that represents the item on the legend.

The default implementation is made for QwtPlotCurve and returns a QwtLegendItem(), but an item could be represented by any type of widget, by overloading legendItem() and updateLegend().

Returns:: QwtLegendItem()

See also:: updateLegend() QwtLegend()

Implements QwtLegendItemManager.

Definition at line 407 of file qwt_plot_item.cpp.

Referenced by attach(), updateLegend(), and QwtPlotCurve::updateLegend().

{
    return new QwtLegendItem;
}

QRect QwtPlotItem::paintRect	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap
	)		const

Calculate the bounding paint rect of 2 maps.

Parameters:

xMap	X map
yMap	X map

Returns:: Bounding rect of the scale maps

Definition at line 509 of file qwt_plot_item.cpp.

References QwtScaleMap::p1(), and QwtScaleMap::pDist().

Referenced by QwtPlotRasterItem::draw().

{
    const QRect rect( qRound(xMap.p1()), qRound(yMap.p1()),
        qRound(xMap.pDist()), qRound(yMap.pDist()) );

    return rect;
}

QwtPlot * QwtPlotItem::plot ( ) const

Return attached plot.

Definition at line 126 of file qwt_plot_item.cpp.

References QwtPlotItem::PrivateData::plot.

Referenced by attach(), QwtPlotCurve::closestPoint(), QwtPlotCurve::draw(), QwtPlotScaleItem::setScaleDivFromAxis(), and QwtPlotScaleItem::setScaleDraw().

{ 
    return d_data->plot; 
}

int QwtPlotItem::rtti ( ) const [virtual]

Return rtti for the specific class represented. QwtPlotItem is simply a virtual interface class, and base classes will implement this method with specific rtti values so a user can differentiate them.

The rtti value is useful for environments, where the runtime type information is disabled and it is not possible to do a dynamic_cast<...>.

Returns:: rtti value

See also:: RttiValues

Reimplemented in QwtPlotCurve, QwtPlotGrid, QwtPlotMarker, QwtPlotScaleItem, QwtPlotSpectrogram, and QwtPlotSvgItem.

Definition at line 120 of file qwt_plot_item.cpp.

References Rtti_PlotItem.

Referenced by QwtPlotPrintFilter::apply(), QwtPlotDict::detachItems(), QwtPlot::drawItems(), and QwtPlotPrintFilter::reset().

{
    return Rtti_PlotItem;
}

QwtDoubleRect QwtPlotItem::scaleRect	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap
	)		const

Calculate the bounding scale rect of 2 maps.

Parameters:

xMap	X map
yMap	X map

Returns:: Bounding rect of the scale maps

Definition at line 494 of file qwt_plot_item.cpp.

References QwtScaleMap::s1(), and QwtScaleMap::sDist().

{
    return QwtDoubleRect(xMap.s1(), yMap.s1(), 
        xMap.sDist(), yMap.sDist() );
}

void QwtPlotItem::setAxis	(	int	xAxis,
		int	yAxis
	)

Set X and Y axis

The item will painted according to the coordinates its Axes.

Parameters:

xAxis	X Axis
yAxis	Y Axis

See also:: setXAxis(), setYAxis(), xAxis(), yAxis()

Definition at line 332 of file qwt_plot_item.cpp.

References itemChanged(), xAxis(), QwtPlotItem::PrivateData::xAxis, QwtPlot::xBottom, QwtPlot::xTop, yAxis(), QwtPlotItem::PrivateData::yAxis, QwtPlot::yLeft, and QwtPlot::yRight.

{
    if (xAxis == QwtPlot::xBottom || xAxis == QwtPlot::xTop )
       d_data->xAxis = xAxis;

    if (yAxis == QwtPlot::yLeft || yAxis == QwtPlot::yRight )
       d_data->yAxis = yAxis;

    itemChanged();    
}

void QwtPlotItem::setItemAttribute	(	ItemAttribute	attribute,
		bool	on = `true`
	)

Toggle an item attribute

Parameters:

attribute	Attribute type
on	true/false

See also:: testItemAttribute(), ItemAttribute

Definition at line 207 of file qwt_plot_item.cpp.

References QwtPlotItem::PrivateData::attributes, and itemChanged().

Referenced by QwtPlotCurve::init(), and QwtPlotSpectrogram::QwtPlotSpectrogram().

{
    if ( bool(d_data->attributes & attribute) != on )
    {
        if ( on )
            d_data->attributes |= attribute;
        else
            d_data->attributes &= ~attribute;

        itemChanged();
    }
}

void QwtPlotItem::setTitle ( const QString & title )

Set a new title

Parameters:

title Title

See also:: title()

Definition at line 170 of file qwt_plot_item.cpp.

{
    setTitle(QwtText(title));
}

void QwtPlotItem::setTitle ( const QwtText & title )

Set a new title

Parameters:

title Title

See also:: title()

Definition at line 181 of file qwt_plot_item.cpp.

References itemChanged(), title(), and QwtPlotItem::PrivateData::title.

{
    if ( d_data->title != title )
    {
        d_data->title = title; 
        itemChanged();
    }
}

void QwtPlotItem::setVisible ( bool on ) [virtual]

Show/Hide the item

Parameters:

on	Show if true, otherwise hide

See also:: isVisible(), show(), hide()

Definition at line 287 of file qwt_plot_item.cpp.

References QwtPlotItem::PrivateData::isVisible, and itemChanged().

Referenced by hide(), and show().

{ 
    if ( on != d_data->isVisible )
    {
        d_data->isVisible = on; 
        itemChanged(); 
    }
}

void QwtPlotItem::setXAxis ( int axis )

Set the X axis

The item will painted according to the coordinates its Axes.

Parameters:

axis X Axis

See also:: setAxis(), setYAxis(), xAxis()

Definition at line 351 of file qwt_plot_item.cpp.

References itemChanged(), QwtPlotItem::PrivateData::xAxis, QwtPlot::xBottom, and QwtPlot::xTop.

{
    if (axis == QwtPlot::xBottom || axis == QwtPlot::xTop )
    {
       d_data->xAxis = axis;
       itemChanged();    
    }
}

void QwtPlotItem::setYAxis ( int axis )

Set the Y axis

The item will painted according to the coordinates its Axes.

Parameters:

axis Y Axis

See also:: setAxis(), setXAxis(), yAxis()

Definition at line 368 of file qwt_plot_item.cpp.

References itemChanged(), QwtPlotItem::PrivateData::yAxis, QwtPlot::yLeft, and QwtPlot::yRight.

{
    if (axis == QwtPlot::yLeft || axis == QwtPlot::yRight )
    {
       d_data->yAxis = axis;
       itemChanged();   
    }
}

void QwtPlotItem::setZ ( double z )

Set the z value.

Plot items are painted in increasing z-order.

Parameters:

z Z-value

See also:: z(), QwtPlotDict::itemList()

Definition at line 149 of file qwt_plot_item.cpp.

References itemChanged(), QwtPlotItem::PrivateData::plot, z(), and QwtPlotItem::PrivateData::z.

Referenced by QwtPlotCurve::init(), QwtPlotGrid::QwtPlotGrid(), QwtPlotMarker::QwtPlotMarker(), QwtPlotScaleItem::QwtPlotScaleItem(), and QwtPlotSpectrogram::QwtPlotSpectrogram().

{ 
    if ( d_data->z != z )
    {
        d_data->z = z; 
        if ( d_data->plot )
        {
            // update the z order
            d_data->plot->attachItem(this, false);
            d_data->plot->attachItem(this, true);
        }
        itemChanged();
    }
}

void QwtPlotItem::show ( )

Show the item.

Definition at line 270 of file qwt_plot_item.cpp.

References setVisible().

{
    setVisible(true);
}

bool QwtPlotItem::testItemAttribute ( ItemAttribute attribute ) const

Test an item attribute

Parameters:

attribute Attribute type

Returns:: true/false

See also:: setItemAttribute(), ItemAttribute

Definition at line 227 of file qwt_plot_item.cpp.

References QwtPlotItem::PrivateData::attributes.

Referenced by QwtPlot::updateAxes(), and updateLegend().

{
    return d_data->attributes & attribute;
}

const QwtText & QwtPlotItem::title ( ) const

Returns:: Title of the item

See also:: setTitle()

Definition at line 194 of file qwt_plot_item.cpp.

References QwtPlotItem::PrivateData::title.

Referenced by QwtPlotItem(), setTitle(), and QwtPlotCurve::updateLegend().

{
    return d_data->title;
}

QRect QwtPlotItem::transform	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QwtDoubleRect &	rect
	)		const

Transform a rectangle

Parameters:

xMap	X map
yMap	Y map
rect	Rectangle in scale coordinates

Returns:: Rectangle in paint coordinates

See also:: invTransform()

Definition at line 528 of file qwt_plot_item.cpp.

References QwtDoubleRect::bottom(), QwtDoubleRect::left(), QwtDoubleRect::right(), QwtDoubleRect::top(), and QwtScaleMap::transform().

Referenced by QwtPlotSvgItem::draw(), QwtPlotSpectrogram::draw(), QwtPlotRasterItem::draw(), and QwtPlotSpectrogram::renderImage().

{
    int x1 = qRound(xMap.transform(rect.left()));
    int x2 = qRound(xMap.transform(rect.right()));
    int y1 = qRound(yMap.transform(rect.top()));
    int y2 = qRound(yMap.transform(rect.bottom()));

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

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

void QwtPlotItem::updateLegend ( QwtLegend * legend ) const [virtual]

Update the widget that represents the item on the legend.

updateLegend() is called from itemChanged() to adopt the widget representing the item on the legend to its new configuration.

The default implementation is made for QwtPlotCurve and updates a QwtLegendItem(), but an item could be represented by any type of widget, by overloading legendItem() and updateLegend().

Parameters:

legend Legend

See also:: legendItem(), itemChanged(), QwtLegend()

Implements QwtLegendItemManager.

Reimplemented in QwtPlotCurve.

Definition at line 426 of file qwt_plot_item.cpp.

References QwtLegend::find(), QwtLegend::insert(), QwtLegend::itemMode(), Legend, legendItem(), QwtPlotItem::PrivateData::plot, QwtLegendItem::setItemMode(), QwtLegendItem::setText(), testItemAttribute(), and QwtPlotItem::PrivateData::title.

Referenced by itemChanged().

{
    if ( !legend )
        return;

    QWidget *lgdItem = legend->find(this);
    if ( testItemAttribute(QwtPlotItem::Legend) )
    {
        if ( lgdItem == NULL )
        {
            lgdItem = legendItem();
            if ( lgdItem )
            {
                if ( lgdItem->inherits("QwtLegendItem") )
                {
                    QwtLegendItem *label = (QwtLegendItem *)lgdItem;
                    label->setItemMode(legend->itemMode());

                    if ( d_data->plot )
                    {
                        QObject::connect(label, SIGNAL(clicked()), 
                            d_data->plot, SLOT(legendItemClicked()));
                        QObject::connect(label, SIGNAL(checked(bool)), 
                            d_data->plot, SLOT(legendItemChecked(bool)));
                    }
                }
                legend->insert(this, lgdItem);
            }
        }
        if ( lgdItem && lgdItem->inherits("QwtLegendItem") )
        {
            QwtLegendItem* label = (QwtLegendItem*)lgdItem;
            if ( label )
                label->setText(d_data->title);
        }
    }
    else
    {
        delete lgdItem;
    }
}

void QwtPlotItem::updateScaleDiv	(	const QwtScaleDiv &	,
		const QwtScaleDiv &
	)		`[virtual]`

Update the item to changes of the axes scale division.

Update the item, when the axes of plot have changed. The default implementation does nothing, but items that depend on the scale division (like QwtPlotGrid()) have to reimplement updateScaleDiv()

Parameters: