qwt_plot_item.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_plot_item.h"
#include "qwt_text.h"
#include "qwt_plot.h"
#include "qwt_legend.h"
#include "qwt_legend_item.h"
#include "qwt_scale_div.h"
#include <qpainter.h>

class QwtPlotItem::PrivateData
{
public:
    PrivateData():
        plot( NULL ),
        isVisible( true ),
        renderHints( 0 ),
        z( 0.0 )
    {
    }

    mutable QwtPlot *plot;

    bool isVisible;
    QwtPlotItem::RenderHints renderHints;
    double z;

    QwtText title;
};

/*!
   Constructor
   \param title Title of the item
*/
QwtPlotItem::QwtPlotItem( const QwtText &title )
{
    d_data = new PrivateData;
    d_data->title = title;
}

//! Destroy the QwtPlotItem
QwtPlotItem::~QwtPlotItem()
{
    attach( NULL );
    delete d_data;
}

/*!
  \brief 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.

  \param plot Plot widget
  \sa detach()
*/
void QwtPlotItem::attach( QwtPlot *plot )
{
    if ( plot == d_data->plot )
        return;

    // remove the item from the previous plot

    if ( d_data->plot )
    {
        if ( d_data->plot->legend() )
            d_data->plot->legend()->remove( this );

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

    d_data->plot = plot;

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

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

/*!
   \brief This method detaches a QwtPlotItem from any 
          QwtPlot it has been associated with.

   detach() is equivalent to calling attach( NULL )
   \sa attach()
*/
void QwtPlotItem::detach()
{
    attach( NULL );
}

//! Return attached plot
QwtPlot *QwtPlotItem::plot() const
{
    return d_data->plot;
}

/*!
   Plot items are painted in increasing z-order.

   \return setZ(), QwtPlotDict::itemList()
*/
double QwtPlotItem::z() const
{
    return d_data->z;
}

/*!
   \brief Set the z value

   Plot items are painted in increasing z-order.

   \param z Z-value
   \sa z(), QwtPlotDict::itemList()
*/
void QwtPlotItem::setZ( double z )
{
    if ( d_data->z != z )
    {
        if ( d_data->plot ) // update the z order
            d_data->plot->attachItem( this, false );

        d_data->z = z;

        if ( d_data->plot )
            d_data->plot->attachItem( this, true );

        itemChanged();
    }
}

/*!
   Set a new title

   \param title Title
   \sa title()
*/
void QwtPlotItem::setTitle( const QString &title )
{
    setTitle( QwtText( title ) );
}

/*!
   Set a new title

   \param title Title
   \sa title()
*/
void QwtPlotItem::setTitle( const QwtText &title )
{
    if ( d_data->title != title )
    {
        d_data->title = title;
        itemChanged();
    }
}

/*!
   \return Title of the item
   \sa setTitle()
*/
const QwtText &QwtPlotItem::title() const
{
    return d_data->title;
}

/*!
   Toggle an render hint

   \param hint Render hint
   \param on true/false

   \sa testRenderHint(), RenderHint
*/
void QwtPlotItem::setRenderHint( RenderHint hint, bool on )
{
    if ( ( ( d_data->renderHints & hint ) != 0 ) != on )
    {
        if ( on )
            d_data->renderHints |= hint;
        else
            d_data->renderHints &= ~hint;

        itemChanged();
    }
}

/*!
   Test a render hint

   \param hint Render hint
   \return true/false
   \sa setRenderHint(), RenderHint
*/
bool QwtPlotItem::testRenderHint( RenderHint hint ) const
{
    return ( d_data->renderHints & hint );
}

//! Show the item
void QwtPlotItem::show()
{
    setVisible( true );
}

//! Hide the item
void QwtPlotItem::hide()
{
    setVisible( false );
}

/*!
    Show/Hide the item

    \param on Show if true, otherwise hide
    \sa isVisible(), show(), hide()
*/
void QwtPlotItem::setVisible( bool on )
{
    if ( on != d_data->isVisible )
    {
        d_data->isVisible = on;
        itemChanged();
    }
}

/*!
    \return true if visible
    \sa setVisible(), show(), hide()
*/
bool QwtPlotItem::isVisible() const
{
    return d_data->isVisible;
}

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

   \sa updateLegend()
*/
void QwtPlotItem::itemChanged()
{
    if ( d_data->plot )
    {
        if ( d_data->plot->legend() )
            updateLegend( d_data->plot->legend() );
    }
}

/*!
   \return An invalid bounding rect: QRectF(1.0, 1.0, -2.0, -2.0)
*/
QRectF QwtPlotItem::boundingRect() const
{
    return QRectF( 1.0, 1.0, -2.0, -2.0 ); // invalid
}

/*!
   \brief Allocate the widget that represents the item on the legend

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

   \return QwtLegendItem()
   \sa updateLegend() QwtLegend()
*/
QWidget *QwtPlotItem::legendItem() const
{
    QwtLegendItem *item = new QwtLegendItem;
    return item;
}

/*!
   \brief 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 updates a QwtLegendItem(), 
   but an item could be represented by any type of widget,
   by overloading legendItem() and updateLegend().

   \param legend Legend

   \sa legendItem(), itemChanged(), QwtLegend()
*/
void QwtPlotItem::updateLegend( QwtLegend *legend ) const
{
    if ( legend == NULL )
        return;

    QWidget *lgdItem = legend->find( this );
    if ( !d_data->title.isNull() )
    {
        if ( lgdItem == NULL )
        {
            lgdItem = legendItem();
            if ( lgdItem )
                legend->insert( this, lgdItem );
        }
        if ( lgdItem && lgdItem->inherits( "QwtLegendItem" ) )
        {
            QwtLegendItem* label = ( QwtLegendItem* )lgdItem;
            if ( label )
            {
                // paint the identifier
                const QSize sz = label->identifierSize();

                QPixmap identifier( sz.width(), sz.height() );
                identifier.fill( Qt::transparent );

                QPainter painter( &identifier );
                painter.setRenderHint( QPainter::Antialiasing,
                    testRenderHint( QwtPlotItem::RenderAntialiased ) );
                drawLegendIdentifier( &painter,
                    QRect( 0, 0, sz.width(), sz.height() ) );
                painter.end();

                const bool doUpdate = label->updatesEnabled();
                if ( doUpdate )
                    label->setUpdatesEnabled( false );

                label->setText( title() );
                label->setIdentifier( identifier );

                if ( doUpdate )
                    label->setUpdatesEnabled( true );

                label->update();
            }
        }
    }
    else
    {
        if ( lgdItem )
        {
            lgdItem->hide();
            lgdItem->deleteLater();
        }
    }
}

/*!
   \brief Calculate the bounding scale rect of 2 maps

   \param xMap X map
   \param yMap X map

   \return Bounding scale rect of the scale maps, normalized
*/
QRectF QwtPlotItem::scaleRect( const QwtScaleMap &xMap,
    const QwtScaleMap &yMap ) const
{
    return QRectF( xMap.s1(), yMap.s1(),
        xMap.sDist(), yMap.sDist() );
}

/*!
   \brief Calculate the bounding paint rect of 2 maps

   \param xMap X map
   \param yMap X map

   \return Bounding paint rect of the scale maps, normalized
*/
QRectF QwtPlotItem::paintRect( const QwtScaleMap &xMap,
    const QwtScaleMap &yMap ) const
{
    const QRectF rect( xMap.p1(), yMap.p1(),
        xMap.pDist(), yMap.pDist() );

    return rect;
}