qwt_polar_layout.cpp

Go to the documentation of this file.

/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * 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()
{
    d_data = new PrivateData;

    setLegendPosition( QwtPolarPlot::BottomLegend );
    invalidate();
}

QwtPolarLayout::~QwtPolarLayout()
{
    delete d_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;
            d_data->legendRatio = ratio;
            d_data->legendPos = pos;
            break;
        }
        case QwtPolarPlot::LeftLegend:
        case QwtPolarPlot::RightLegend:
        {
            if ( ratio <= 0.0 )
                ratio = 0.5;
            d_data->legendRatio = ratio;
            d_data->legendPos = pos;
            break;
        }
        case QwtPolarPlot::ExternalLegend:
        {
            d_data->legendRatio = ratio; // meaningless
            d_data->legendPos = pos;
            break;
        }
        default:
            break;
    }
}

void QwtPolarLayout::setLegendPosition( QwtPolarPlot::LegendPosition pos )
{
    setLegendPosition( pos, 0.0 );
}

QwtPolarPlot::LegendPosition QwtPolarLayout::legendPosition() const
{
    return d_data->legendPos;
}

void QwtPolarLayout::setLegendRatio( double ratio )
{
    setLegendPosition( legendPosition(), ratio );
}

double QwtPolarLayout::legendRatio() const
{
    return d_data->legendRatio;
}

const QRectF &QwtPolarLayout::titleRect() const
{
    return d_data->titleRect;
}

const QRectF &QwtPolarLayout::legendRect() const
{
    return d_data->legendRect;
}

const QRectF &QwtPolarLayout::canvasRect() const
{
    return d_data->canvasRect;
}

void QwtPolarLayout::invalidate()
{
    d_data->titleRect = d_data->legendRect = d_data->canvasRect = QRect();
}

QRectF QwtPolarLayout::layoutLegend( Options options, QRectF &rect ) const
{
    const QSizeF hint( d_data->layoutData.legend.hint );

    int dim;
    if ( d_data->legendPos == QwtPolarPlot::LeftLegend
        || d_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() * d_data->legendRatio );

        if ( !( options & IgnoreScrollbars ) )
        {
            if ( hint.height() > rect.height() )
            {
                // The legend will need additional
                // space for the vertical scrollbar.

                dim += d_data->layoutData.legend.hScrollExtent;
            }
        }
    }
    else
    {
        dim = qMin( double( hint.height() ), rect.height() * d_data->legendRatio );
        dim = qMax( dim, d_data->layoutData.legend.vScrollExtent );
    }

    QRectF legendRect = rect;
    switch( d_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( d_data->margin, d_data->margin,
        -d_data->margin, -d_data->margin );

    // We extract all layout relevant data from the widgets
    // and save them to d_data->layoutData.

    d_data->layoutData.init( plot, rect );
    if ( !( options & IgnoreLegend )
        && d_data->legendPos != QwtPolarPlot::ExternalLegend
        && plot->legend() && !plot->legend()->isEmpty() )
    {
        d_data->legendRect = layoutLegend( options, rect );
        if ( d_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( d_data->legendPos )
            {
                case QwtPolarPlot::LeftLegend:
                    rect.setLeft( rect.left() + d_data->spacing );
                    break;

                case QwtPolarPlot::RightLegend:
                    rect.setRight( rect.right() - d_data->spacing );
                    break;

                case QwtPolarPlot::TopLegend:
                    rect.setTop( rect.top() + d_data->spacing );
                    break;

                case QwtPolarPlot::BottomLegend:
                    rect.setBottom( rect.bottom() - d_data->spacing );
                    break;

                case QwtPolarPlot::ExternalLegend:
                    break; // suppress compiler warning
            }
        }
    }

    if ( !( options & IgnoreTitle ) &&
        !d_data->layoutData.title.text.isEmpty() )
    {
        int h = d_data->layoutData.title.text.heightForWidth( rect.width() );
        if ( !( options & IgnoreFrames ) )
            h += 2 * d_data->layoutData.title.frameWidth;

        d_data->titleRect = QRectF( rect.x(), rect.y(), rect.width(), h );

        // subtract title
        rect.setTop( rect.top() + h + d_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.

        d_data->canvasRect = rect;
    }
    else
    {
        // In full state we know, that we want
        // to display something circular.

        const int dim = qMin( rect.width(), rect.height() );

        d_data->canvasRect.setX( rect.center().x() - dim / 2 );
        d_data->canvasRect.setY( rect.y() );
        d_data->canvasRect.setSize( QSize( dim, dim ) );
    }

    if ( !d_data->legendRect.isEmpty() )
    {
        if ( d_data->legendPos == QwtPolarPlot::LeftLegend
            || d_data->legendPos == QwtPolarPlot::RightLegend )
        {
            // We prefer to align the legend to the canvas - not to
            // the complete plot - if possible.

            if ( d_data->layoutData.legend.hint.height()
                    < d_data->canvasRect.height() )
            {
                d_data->legendRect.setY( d_data->canvasRect.y() );
                d_data->legendRect.setHeight( d_data->canvasRect.height() );
            }
        }
    }
}