qwt_polar_layout.cpp

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/******************************************************************************
 * QwtPolar Widget Library
 * Copyright (C) 2008   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_polar_layout.h"
#include "qwt_polar_plot.h"
#include "qwt_polar_canvas.h"
#include "qwt_text.h"
#include "qwt_text_label.h"
#include "qwt_legend.h"
 
class QwtPolarLayout::LayoutData
{
  public:
    void init( const QwtPolarPlot*, const QRectF& rect );
 
    struct t_legendData
    {
        int frameWidth;
        int hScrollExtent;
        int vScrollExtent;
        QSizeF hint;
    } legend;
 
    struct t_titleData
    {
        QwtText text;
        int frameWidth;
    } title;
 
    struct t_canvasData
    {
        int frameWidth;
    } canvas;
};
 
void QwtPolarLayout::LayoutData::init(
    const QwtPolarPlot* plot, const QRectF& rect )
{
    // legend
 
    if ( plot->plotLayout()->legendPosition() != QwtPolarPlot::ExternalLegend
        && plot->legend() )
    {
        legend.frameWidth = plot->legend()->frameWidth();
        legend.hScrollExtent =
            plot->legend()->scrollExtent( Qt::Horizontal );
        legend.vScrollExtent =
            plot->legend()->scrollExtent( Qt::Vertical );
 
        const QSizeF hint = plot->legend()->sizeHint();
 
        double w = qMin( hint.width(), rect.width() );
        double h = plot->legend()->heightForWidth( w );
        if ( h == 0.0 )
            h = hint.height();
 
        if ( h > rect.height() )
            w += legend.hScrollExtent;
 
        legend.hint = QSizeF( w, h );
    }
 
    // title
 
    title.frameWidth = 0;
    title.text = QwtText();
 
    if ( plot->titleLabel() )
    {
        const QwtTextLabel* label = plot->titleLabel();
        title.text = label->text();
        if ( !( title.text.testPaintAttribute( QwtText::PaintUsingTextFont ) ) )
            title.text.setFont( label->font() );
 
        title.frameWidth = plot->titleLabel()->frameWidth();
    }
 
    // canvas
 
    canvas.frameWidth = plot->canvas()->frameWidth();
}
 
class QwtPolarLayout::PrivateData
{
  public:
    PrivateData()
        : margin( 0 )
        , spacing( 0 )
    {
    }
 
    QRectF titleRect;
    QRectF legendRect;
    QRectF canvasRect;
 
    QwtPolarLayout::LayoutData layoutData;
 
    QwtPolarPlot::LegendPosition legendPos;
    double legendRatio;
 
    unsigned int margin;
    unsigned int spacing;
};
 
QwtPolarLayout::QwtPolarLayout()
{
    m_data = new PrivateData;
 
    setLegendPosition( QwtPolarPlot::BottomLegend );
    invalidate();
}
 
QwtPolarLayout::~QwtPolarLayout()
{
    delete m_data;
}
 
void QwtPolarLayout::setLegendPosition(
    QwtPolarPlot::LegendPosition pos, double ratio )
{
    if ( ratio > 1.0 )
        ratio = 1.0;
 
    switch( pos )
    {
        case QwtPolarPlot::TopLegend:
        case QwtPolarPlot::BottomLegend:
        {
            if ( ratio <= 0.0 )
                ratio = 0.33;
            m_data->legendRatio = ratio;
            m_data->legendPos = pos;
            break;
        }
        case QwtPolarPlot::LeftLegend:
        case QwtPolarPlot::RightLegend:
        {
            if ( ratio <= 0.0 )
                ratio = 0.5;
            m_data->legendRatio = ratio;
            m_data->legendPos = pos;
            break;
        }
        case QwtPolarPlot::ExternalLegend:
        {
            m_data->legendRatio = ratio; // meaningless
            m_data->legendPos = pos;
            break;
        }
        default:
            break;
    }
}
 
void QwtPolarLayout::setLegendPosition( QwtPolarPlot::LegendPosition pos )
{
    setLegendPosition( pos, 0.0 );
}
 
QwtPolarPlot::LegendPosition QwtPolarLayout::legendPosition() const
{
    return m_data->legendPos;
}
 
void QwtPolarLayout::setLegendRatio( double ratio )
{
    setLegendPosition( legendPosition(), ratio );
}
 
double QwtPolarLayout::legendRatio() const
{
    return m_data->legendRatio;
}
 
const QRectF& QwtPolarLayout::titleRect() const
{
    return m_data->titleRect;
}
 
const QRectF& QwtPolarLayout::legendRect() const
{
    return m_data->legendRect;
}
 
const QRectF& QwtPolarLayout::canvasRect() const
{
    return m_data->canvasRect;
}
 
void QwtPolarLayout::invalidate()
{
    m_data->titleRect = m_data->legendRect = m_data->canvasRect = QRect();
}
 
QRectF QwtPolarLayout::layoutLegend( Options options, QRectF& rect ) const
{
    const QSizeF hint( m_data->layoutData.legend.hint );
 
    int dim;
    if ( m_data->legendPos == QwtPolarPlot::LeftLegend
        || m_data->legendPos == QwtPolarPlot::RightLegend )
    {
        // We don't allow vertical legends to take more than
        // half of the available space.
 
        dim = qMin( double( hint.width() ), rect.width() * m_data->legendRatio );
 
        if ( !( options & IgnoreScrollbars ) )
        {
            if ( hint.height() > rect.height() )
            {
                // The legend will need additional
                // space for the vertical scrollbar.
 
                dim += m_data->layoutData.legend.hScrollExtent;
            }
        }
    }
    else
    {
        dim = qMin( double( hint.height() ), rect.height() * m_data->legendRatio );
        dim = qMax( dim, m_data->layoutData.legend.vScrollExtent );
    }
 
    QRectF legendRect = rect;
    switch( m_data->legendPos )
    {
        case QwtPolarPlot::LeftLegend:
        {
            legendRect.setWidth( dim );
            rect.setLeft( legendRect.right() );
            break;
        }
        case QwtPolarPlot::RightLegend:
        {
            legendRect.setX( rect.right() - dim + 1 );
            legendRect.setWidth( dim );
            rect.setRight( legendRect.left() );
            break;
        }
        case QwtPolarPlot::TopLegend:
        {
            legendRect.setHeight( dim );
            rect.setTop( legendRect.bottom() );
            break;
        }
        case QwtPolarPlot::BottomLegend:
        {
            legendRect.setY( rect.bottom() - dim + 1 );
            legendRect.setHeight( dim );
            rect.setBottom( legendRect.top() );
            break;
        }
        case QwtPolarPlot::ExternalLegend:
            break;
    }
 
    return legendRect;
}
 
void QwtPolarLayout::activate( const QwtPolarPlot* plot,
    const QRectF& boundingRect, Options options )
{
    invalidate();
 
    QRectF rect( boundingRect ); // undistributed rest of the plot rect
    rect.adjust( m_data->margin, m_data->margin,
        -m_data->margin, -m_data->margin );
 
    // We extract all layout relevant data from the widgets
    // and save them to m_data->layoutData.
 
    m_data->layoutData.init( plot, rect );
    if ( !( options & IgnoreLegend )
        && m_data->legendPos != QwtPolarPlot::ExternalLegend
        && plot->legend() && !plot->legend()->isEmpty() )
    {
        m_data->legendRect = layoutLegend( options, rect );
        if ( m_data->layoutData.legend.frameWidth &&
            !( options & IgnoreFrames ) )
        {
            // In case of a frame we have to insert a spacing.
            // Otherwise the leading of the font separates
            // legend and scale/canvas
 
            switch( m_data->legendPos )
            {
                case QwtPolarPlot::LeftLegend:
                    rect.setLeft( rect.left() + m_data->spacing );
                    break;
 
                case QwtPolarPlot::RightLegend:
                    rect.setRight( rect.right() - m_data->spacing );
                    break;
 
                case QwtPolarPlot::TopLegend:
                    rect.setTop( rect.top() + m_data->spacing );
                    break;
 
                case QwtPolarPlot::BottomLegend:
                    rect.setBottom( rect.bottom() - m_data->spacing );
                    break;
 
                case QwtPolarPlot::ExternalLegend:
                    break; // suppress compiler warning
            }
        }
    }
 
    if ( !( options & IgnoreTitle ) &&
        !m_data->layoutData.title.text.isEmpty() )
    {
        int h = m_data->layoutData.title.text.heightForWidth( rect.width() );
        if ( !( options & IgnoreFrames ) )
            h += 2 * m_data->layoutData.title.frameWidth;
 
        m_data->titleRect = QRectF( rect.x(), rect.y(), rect.width(), h );
 
        // subtract title
        rect.setTop( rect.top() + h + m_data->spacing );
    }
 
    if ( plot->zoomPos().radius() > 0.0 || plot->zoomFactor() < 1.0 )
    {
        // In zoomed state we have no idea about the geometry that
        // is best for the plot. So we use the complete rectangle
        // accepting, that there might a lot of space wasted
        // around the plot.
 
        m_data->canvasRect = rect;
    }
    else
    {
        // In full state we know, that we want
        // to display something circular.
 
        const int dim = qMin( rect.width(), rect.height() );
 
        m_data->canvasRect.setX( rect.center().x() - dim / 2 );
        m_data->canvasRect.setY( rect.y() );
        m_data->canvasRect.setSize( QSize( dim, dim ) );
    }
 
    if ( !m_data->legendRect.isEmpty() )
    {
        if ( m_data->legendPos == QwtPolarPlot::LeftLegend
            || m_data->legendPos == QwtPolarPlot::RightLegend )
        {
            // We prefer to align the legend to the canvas - not to
            // the complete plot - if possible.
 
            if ( m_data->layoutData.legend.hint.height()
                < m_data->canvasRect.height() )
            {
                m_data->legendRect.setY( m_data->canvasRect.y() );
                m_data->legendRect.setHeight( m_data->canvasRect.height() );
            }
        }
    }
}