qwt_plot_legenditem.cpp

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/******************************************************************************
 * 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_legenditem.h"
#include "qwt_dyngrid_layout.h"
#include "qwt_text.h"
#include "qwt_graphic.h"
#include "qwt_legend_data.h"
#include "qwt_math.h"

#include <qlayoutitem.h>
#include <qpen.h>
#include <qbrush.h>
#include <qpainter.h>

namespace
{
    class LayoutItem QWT_FINAL : public QLayoutItem
    {
      public:
        LayoutItem( const QwtPlotLegendItem*, const QwtPlotItem* );
        virtual ~LayoutItem();

        const QwtPlotItem* plotItem() const;

        void setData( const QwtLegendData& );
        const QwtLegendData& data() const;

        virtual Qt::Orientations expandingDirections() const QWT_OVERRIDE;
        virtual QRect geometry() const QWT_OVERRIDE;
        virtual bool hasHeightForWidth() const QWT_OVERRIDE;
        virtual int heightForWidth( int ) const QWT_OVERRIDE;
        virtual bool isEmpty() const QWT_OVERRIDE;
        virtual QSize maximumSize() const QWT_OVERRIDE;
        virtual int minimumHeightForWidth( int ) const QWT_OVERRIDE;
        virtual QSize minimumSize() const QWT_OVERRIDE;
        virtual void setGeometry( const QRect& ) QWT_OVERRIDE;
        virtual QSize sizeHint() const QWT_OVERRIDE;

      private:

        const QwtPlotLegendItem* m_legendItem;
        const QwtPlotItem* m_plotItem;
        QwtLegendData m_data;

        QRect m_rect;
    };

    LayoutItem::LayoutItem(
            const QwtPlotLegendItem* legendItem, const QwtPlotItem* plotItem )
        : m_legendItem( legendItem )
        , m_plotItem( plotItem)
    {
    }

    LayoutItem::~LayoutItem()
    {
    }

    const QwtPlotItem* LayoutItem::plotItem() const
    {
        return m_plotItem;
    }

    void LayoutItem::setData( const QwtLegendData& data )
    {
        m_data = data;
    }

    const QwtLegendData& LayoutItem::data() const
    {
        return m_data;
    }

    Qt::Orientations LayoutItem::expandingDirections() const
    {
        return Qt::Horizontal;
    }

    bool LayoutItem::hasHeightForWidth() const
    {
        return !m_data.title().isEmpty();
    }

    int LayoutItem::minimumHeightForWidth( int w ) const
    {
        return m_legendItem->heightForWidth( m_data, w );
    }

    int LayoutItem::heightForWidth( int w ) const
    {
        return m_legendItem->heightForWidth( m_data, w );
    }

    bool LayoutItem::isEmpty() const
    {
        return false;
    }

    QSize LayoutItem::maximumSize() const
    {
        return QSize( QLAYOUTSIZE_MAX, QLAYOUTSIZE_MAX );
    }

    QSize LayoutItem::minimumSize() const
    {
        return m_legendItem->minimumSize( m_data );
    }

    QSize LayoutItem::sizeHint() const
    {
        return minimumSize();
    }

    void LayoutItem::setGeometry( const QRect& rect )
    {
        m_rect = rect;
    }

    QRect LayoutItem::geometry() const
    {
        return m_rect;
    }
}

class QwtPlotLegendItem::PrivateData
{
  public:
    PrivateData()
        : itemMargin( 4 )
        , itemSpacing( 4 )
        , borderRadius( 0.0 )
        , borderPen( Qt::NoPen )
        , backgroundBrush( Qt::NoBrush )
        , backgroundMode( QwtPlotLegendItem::LegendBackground )
        , canvasAlignment( Qt::AlignRight | Qt::AlignBottom )
    {
        canvasOffset[ 0 ] = canvasOffset[1] = 10;
        layout = new QwtDynGridLayout();
        layout->setMaxColumns( 2 );

        layout->setSpacing( 0 );
        layout->setContentsMargins( 0, 0, 0, 0 );
    }

    ~PrivateData()
    {
        delete layout;
    }

    QFont font;
    QPen textPen;
    int itemMargin;
    int itemSpacing;

    double borderRadius;
    QPen borderPen;
    QBrush backgroundBrush;
    QwtPlotLegendItem::BackgroundMode backgroundMode;

    int canvasOffset[2];
    Qt::Alignment canvasAlignment;

    QMap< const QwtPlotItem*, QList< LayoutItem* > > map;
    QwtDynGridLayout* layout;
};

QwtPlotLegendItem::QwtPlotLegendItem()
    : QwtPlotItem( QwtText( "Legend" ) )
{
    m_data = new PrivateData;

    setItemInterest( QwtPlotItem::LegendInterest, true );
    setZ( 100.0 );
}

QwtPlotLegendItem::~QwtPlotLegendItem()
{
    clearLegend();
    delete m_data;
}

int QwtPlotLegendItem::rtti() const
{
    return QwtPlotItem::Rtti_PlotLegend;
}

void QwtPlotLegendItem::setAlignmentInCanvas( Qt::Alignment alignment )
{
    if ( m_data->canvasAlignment != alignment )
    {
        m_data->canvasAlignment = alignment;
        itemChanged();
    }
}

Qt::Alignment QwtPlotLegendItem::alignmentInCanvas() const
{
    return m_data->canvasAlignment;
}

void QwtPlotLegendItem::setMaxColumns( uint maxColumns )
{
    if ( maxColumns != m_data->layout->maxColumns() )
    {
        m_data->layout->setMaxColumns( maxColumns );
        itemChanged();
    }
}

uint QwtPlotLegendItem::maxColumns() const
{
    return m_data->layout->maxColumns();
}

void QwtPlotLegendItem::setMargin( int margin )
{
    margin = qMax( margin, 0 );
    if ( margin != this->margin() )
    {
        m_data->layout->setContentsMargins(
            margin, margin, margin, margin );

        itemChanged();
    }
}

int QwtPlotLegendItem::margin() const
{
    int left;
    m_data->layout->getContentsMargins( &left, NULL, NULL, NULL );

    return left;
}

void QwtPlotLegendItem::setSpacing( int spacing )
{
    spacing = qMax( spacing, 0 );
    if ( spacing != m_data->layout->spacing() )
    {
        m_data->layout->setSpacing( spacing );
        itemChanged();
    }
}

int QwtPlotLegendItem::spacing() const
{
    return m_data->layout->spacing();
}

void QwtPlotLegendItem::setItemMargin( int margin )
{
    margin = qMax( margin, 0 );
    if ( margin != m_data->itemMargin )
    {
        m_data->itemMargin = margin;

        m_data->layout->invalidate();
        itemChanged();
    }
}

int QwtPlotLegendItem::itemMargin() const
{
    return m_data->itemMargin;
}

void QwtPlotLegendItem::setItemSpacing( int spacing )
{
    spacing = qMax( spacing, 0 );
    if ( spacing != m_data->itemSpacing )
    {
        m_data->itemSpacing = spacing;

        m_data->layout->invalidate();
        itemChanged();
    }

}

int QwtPlotLegendItem::itemSpacing() const
{
    return m_data->itemSpacing;
}

void QwtPlotLegendItem::setFont( const QFont& font )
{
    if ( font != m_data->font )
    {
        m_data->font = font;

        m_data->layout->invalidate();
        itemChanged();
    }
}

QFont QwtPlotLegendItem::font() const
{
    return m_data->font;
}

void QwtPlotLegendItem::setOffsetInCanvas(
    Qt::Orientations orientations, int numPixels )
{
    if ( numPixels < 0 )
        numPixels = -1;

    bool isChanged = false;

    int* offset = m_data->canvasOffset;

    if ( orientations & Qt::Horizontal )
    {
        if ( numPixels != offset[0] )
        {
            offset[0] = numPixels;
            isChanged = true;
        }
    }

    if ( orientations & Qt::Vertical )
    {
        if ( numPixels != offset[1] )
        {
            offset[1] = numPixels;
            isChanged = true;
        }
    }

    if ( isChanged )
        itemChanged();
}

int QwtPlotLegendItem::offsetInCanvas(
    Qt::Orientation orientation ) const
{
    const int index = ( orientation == Qt::Vertical ) ? 1 : 0;
    return m_data->canvasOffset[index];
}

void QwtPlotLegendItem::setBorderRadius( double radius )
{
    radius = qwtMaxF( 0.0, radius );

    if ( radius != m_data->borderRadius )
    {
        m_data->borderRadius = radius;
        itemChanged();
    }
}

double QwtPlotLegendItem::borderRadius() const
{
    return m_data->borderRadius;
}

void QwtPlotLegendItem::setBorderPen( const QPen& pen )
{
    if ( m_data->borderPen != pen )
    {
        m_data->borderPen = pen;
        itemChanged();
    }
}

QPen QwtPlotLegendItem::borderPen() const
{
    return m_data->borderPen;
}

void QwtPlotLegendItem::setBackgroundBrush( const QBrush& brush )
{
    if ( m_data->backgroundBrush != brush )
    {
        m_data->backgroundBrush = brush;
        itemChanged();
    }
}

QBrush QwtPlotLegendItem::backgroundBrush() const
{
    return m_data->backgroundBrush;
}

void QwtPlotLegendItem::setBackgroundMode( BackgroundMode mode )
{
    if ( mode != m_data->backgroundMode )
    {
        m_data->backgroundMode = mode;
        itemChanged();
    }
}

QwtPlotLegendItem::BackgroundMode QwtPlotLegendItem::backgroundMode() const
{
    return m_data->backgroundMode;
}

void QwtPlotLegendItem::setTextPen( const QPen& pen )
{
    if ( m_data->textPen != pen )
    {
        m_data->textPen = pen;
        itemChanged();
    }
}

QPen QwtPlotLegendItem::textPen() const
{
    return m_data->textPen;
}

void QwtPlotLegendItem::draw( QPainter* painter,
    const QwtScaleMap& xMap, const QwtScaleMap& yMap,
    const QRectF& canvasRect ) const
{
    Q_UNUSED( xMap );
    Q_UNUSED( yMap );

    m_data->layout->setGeometry( geometry( canvasRect ) );
    if ( m_data->layout->geometry().isEmpty() )
    {
        // don't draw a legend when having no content
        return;
    }

    if ( m_data->backgroundMode == QwtPlotLegendItem::LegendBackground )
        drawBackground( painter, m_data->layout->geometry() );

    for ( int i = 0; i < m_data->layout->count(); i++ )
    {
        const LayoutItem* layoutItem =
            static_cast< LayoutItem* >( m_data->layout->itemAt( i ) );

        if ( m_data->backgroundMode == QwtPlotLegendItem::ItemBackground )
            drawBackground( painter, layoutItem->geometry() );

        painter->save();

        drawLegendData( painter, layoutItem->plotItem(),
            layoutItem->data(), layoutItem->geometry() );

        painter->restore();
    }
}

void QwtPlotLegendItem::drawBackground(
    QPainter* painter, const QRectF& rect ) const
{
    painter->save();

    painter->setPen( m_data->borderPen );
    painter->setBrush( m_data->backgroundBrush );

    const double radius = m_data->borderRadius;
    painter->drawRoundedRect( rect, radius, radius );

    painter->restore();
}

QRect QwtPlotLegendItem::geometry( const QRectF& canvasRect ) const
{
    QRect rect;
    rect.setSize( m_data->layout->sizeHint() );

    if ( m_data->canvasAlignment & Qt::AlignHCenter )
    {
        int x = qRound( canvasRect.center().x() );
        rect.moveCenter( QPoint( x, rect.center().y() ) );
    }
    else if ( m_data->canvasAlignment & Qt::AlignRight )
    {
        const int offset = offsetInCanvas( Qt::Horizontal );
        rect.moveRight( qwtFloor( canvasRect.right() - offset ) );
    }
    else
    {
        const int offset = offsetInCanvas( Qt::Horizontal );
        rect.moveLeft( qwtCeil( canvasRect.left() + offset ) );
    }

    if ( m_data->canvasAlignment & Qt::AlignVCenter )
    {
        int y = qRound( canvasRect.center().y() );
        rect.moveCenter( QPoint( rect.center().x(), y ) );
    }
    else if ( m_data->canvasAlignment & Qt::AlignBottom )
    {
        const int offset = offsetInCanvas( Qt::Vertical );
        rect.moveBottom( qwtFloor( canvasRect.bottom() - offset ) );
    }
    else
    {
        const int offset = offsetInCanvas( Qt::Vertical );
        rect.moveTop( qwtCeil( canvasRect.top() + offset ) );
    }

    return rect;
}

void QwtPlotLegendItem::updateLegend( const QwtPlotItem* plotItem,
    const QList< QwtLegendData >& data )
{
    if ( plotItem == NULL )
        return;

    QList< LayoutItem* > layoutItems;

    QMap< const QwtPlotItem*, QList< LayoutItem* > >::const_iterator it =
        m_data->map.constFind( plotItem );
    if ( it != m_data->map.constEnd() )
        layoutItems = it.value();

    bool changed = false;

    if ( data.size() != layoutItems.size() )
    {
        changed = true;

        for ( int i = 0; i < layoutItems.size(); i++ )
        {
            m_data->layout->removeItem( layoutItems[i] );
            delete layoutItems[i];
        }
        layoutItems.clear();

        if ( it != m_data->map.constEnd() )
            m_data->map.remove( plotItem );

        if ( !data.isEmpty() )
        {
            layoutItems.reserve( data.size() );

            for ( int i = 0; i < data.size(); i++ )
            {
                LayoutItem* layoutItem =
                    new LayoutItem( this, plotItem );
                m_data->layout->addItem( layoutItem );
                layoutItems += layoutItem;
            }

            m_data->map.insert( plotItem, layoutItems );
        }
    }

    for ( int i = 0; i < data.size(); i++ )
    {
        if ( layoutItems[i]->data().values() != data[i].values() )
        {
            layoutItems[i]->setData( data[i] );
            changed = true;
        }
    }

    if ( changed )
    {
        m_data->layout->invalidate();
        itemChanged();
    }
}

void QwtPlotLegendItem::clearLegend()
{
    if ( !m_data->map.isEmpty() )
    {
        m_data->map.clear();

        for ( int i = m_data->layout->count() - 1; i >= 0; i-- )
            delete m_data->layout->takeAt( i );

        itemChanged();
    }
}

void QwtPlotLegendItem::drawLegendData( QPainter* painter,
    const QwtPlotItem* plotItem, const QwtLegendData& data,
    const QRectF& rect ) const
{
    Q_UNUSED( plotItem );

    const int m = m_data->itemMargin;
    const QRectF r = rect.toRect().adjusted( m, m, -m, -m );

    painter->setClipRect( r, Qt::IntersectClip );

    int titleOff = 0;

    const QwtGraphic graphic = data.icon();
    if ( !graphic.isEmpty() )
    {
        QRectF iconRect( r.topLeft(), graphic.defaultSize() );

        iconRect.moveCenter(
            QPoint( iconRect.center().x(), rect.center().y() ) );

        graphic.render( painter, iconRect, Qt::KeepAspectRatio );

        titleOff += iconRect.width() + m_data->itemSpacing;
    }

    const QwtText text = data.title();
    if ( !text.isEmpty() )
    {
        painter->setPen( textPen() );
        painter->setFont( font() );

        const QRectF textRect = r.adjusted( titleOff, 0, 0, 0 );
        text.draw( painter, textRect );
    }
}

QSize QwtPlotLegendItem::minimumSize( const QwtLegendData& data ) const
{
    QSize size( 2 * m_data->itemMargin, 2 * m_data->itemMargin );

    if ( !data.isValid() )
        return size;

    const QwtGraphic graphic = data.icon();
    const QwtText text = data.title();

    int w = 0;
    int h = 0;

    if ( !graphic.isNull() )
    {
        w = graphic.width();
        h = graphic.height();
    }

    if ( !text.isEmpty() )
    {
        const QSizeF sz = text.textSize( font() );

        w += qwtCeil( sz.width() );
        h = qMax( h, qwtCeil( sz.height() ) );
    }

    if ( graphic.width() > 0 && !text.isEmpty() )
        w += m_data->itemSpacing;

    size += QSize( w, h );
    return size;
}

int QwtPlotLegendItem::heightForWidth(
    const QwtLegendData& data, int width ) const
{
    width -= 2 * m_data->itemMargin;

    const QwtGraphic graphic = data.icon();
    const QwtText text = data.title();

    if ( text.isEmpty() )
        return graphic.height();

    if ( graphic.width() > 0 )
        width -= graphic.width() + m_data->itemSpacing;

    int h = text.heightForWidth( width, font() );
    h += 2 * m_data->itemMargin;

    return qMax( graphic.height(), h );
}

QList< const QwtPlotItem* > QwtPlotLegendItem::plotItems() const
{
    return m_data->map.keys();
}

QList< QRect > QwtPlotLegendItem::legendGeometries(
    const QwtPlotItem* plotItem ) const
{
    QList< LayoutItem* > layoutItems;

    QMap< const QwtPlotItem*, QList< LayoutItem* > >::const_iterator it =
        m_data->map.constFind( plotItem );
    if ( it != m_data->map.constEnd() )
        layoutItems = it.value();

    QList< QRect > geometries;
    geometries.reserve(layoutItems.size() );

    for ( int i = 0; i < layoutItems.size(); i++ )
        geometries += layoutItems[i]->geometry();

    return geometries;
}