qwt_scale_draw.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_scale_draw.h"
#include "qwt_scale_div.h"
#include "qwt_scale_map.h"
#include "qwt_math.h"
#include "qwt_painter.h"
#include "qwt_text.h"
 
#include <qpainter.h>
#include <qpaintengine.h>
#include <qmath.h>
 
static inline double qwtEffectivePenWidth( const QwtAbstractScaleDraw* scaleDraw )
{
    return qwtMaxF( scaleDraw->penWidthF(), 1.0 );
}
 
namespace QwtScaleRendererReal
{
    inline qreal penWidth( const QPainter* painter, const QwtScaleDraw* scaleDraw )
    {
        qreal width = scaleDraw->penWidthF();
#if 1
        if ( width <= 0.0 )
            width = 1.0;
#endif
 
        if ( painter->pen().isCosmetic() )
        {
            const QTransform& transform = painter->transform();
 
            switch ( scaleDraw->alignment() )
            {
                case QwtScaleDraw::LeftScale:
                case QwtScaleDraw::RightScale:
                {
                    width /= transform.m11();
                    break;
                }
                case QwtScaleDraw::TopScale:
                case QwtScaleDraw::BottomScale:
                {
                    width /= transform.m22();
                    break;
                }
            }
        }
 
        return width;
    }
 
    inline void drawBackbone( QPainter* painter, const QwtScaleDraw* scaleDraw )
    {
        const qreal pw2 = 0.5 * penWidth( painter, scaleDraw );
 
        const QPointF pos = scaleDraw->pos();
        const qreal length = scaleDraw->length();
 
        switch ( scaleDraw->alignment() )
        {
            case QwtScaleDraw::LeftScale:
            {
                const qreal x = pos.x() + 1.0 - pw2;
                QwtPainter::drawLine( painter, x, pos.y(), x, pos.y() + length );
 
                break;
            }
            case QwtScaleDraw::RightScale:
            {
                const qreal x = pos.x() - 1.0 + pw2;
                QwtPainter::drawLine( painter, x, pos.y(), x, pos.y() + length );
 
                break;
            }
            case QwtScaleDraw::TopScale:
            {
                const qreal y = pos.y() + 1.0 - pw2;
                QwtPainter::drawLine( painter, pos.x(), y, pos.x() + length, y );
 
                break;
            }
            case QwtScaleDraw::BottomScale:
            {
                const qreal y = pos.y() - 1.0 + pw2;
                QwtPainter::drawLine( painter, pos.x(), y, pos.x() + length, y );
 
                break;
            }
        }
    }
 
    inline void drawTick( QPainter* painter,
        const QwtScaleDraw* scaleDraw, qreal tickPos, qreal tickLength )
    {
        const QPointF pos = scaleDraw->pos();
 
        qreal pw = 0.0;
 
        if ( scaleDraw->hasComponent( QwtScaleDraw::Backbone ) )
            pw = penWidth( painter, scaleDraw );
 
        const qreal length = tickLength + pw;
 
        /*
            Those correction offsets have been found by try and error.
            They need to be understood and replaced by a calculation,
            that makes sense. TODO ...
         */
        const qreal off1 = 1.0;
        const qreal off2 = ( scaleDraw->penWidthF() <= 0.0 ) ? 0.5 : 0.0;
 
        switch ( scaleDraw->alignment() )
        {
            case QwtScaleDraw::LeftScale:
            {
                const qreal x = pos.x() + off1 - off2;
                QwtPainter::drawLine( painter, x, tickPos, x - length, tickPos );
 
                break;
            }
            case QwtScaleDraw::RightScale:
            {
                const qreal x = pos.x() - off1 + off2;
                QwtPainter::drawLine( painter, x, tickPos, x + length, tickPos );
                break;
            }
            case QwtScaleDraw::TopScale:
            {
                const qreal y = pos.y() + off1 - 2 * off2;
                QwtPainter::drawLine( painter, tickPos, y, tickPos, y - length );
 
                break;
            }
            case QwtScaleDraw::BottomScale:
            {
                const qreal y = pos.y() - off1 + off2;
                QwtPainter::drawLine( painter, tickPos, y, tickPos, y + length );
 
                break;
            }
        }
    }
}
 
namespace QwtScaleRendererInt
{
    inline void drawBackbone( QPainter* painter, const QwtScaleDraw* scaleDraw )
    {
        const int pw = qMax( qRound( scaleDraw->penWidthF() ), 1 );
 
        const qreal length = scaleDraw->length();
        const QPointF pos = scaleDraw->pos();
 
        switch ( scaleDraw->alignment() )
        {
            case QwtScaleDraw::LeftScale:
            {
                const qreal x = qRound( pos.x() - ( pw - 1 ) / 2 );
                QwtPainter::drawLine( painter, x, pos.y(), x, pos.y() + length );
 
                break;
            }
            case QwtScaleDraw::RightScale:
            {
                const qreal x = qRound( pos.x() + pw / 2 );
                QwtPainter::drawLine( painter, x, pos.y(), x, pos.y() + length );
 
                break;
            }
            case QwtScaleDraw::TopScale:
            {
                const qreal y = qRound( pos.y() - ( pw - 1 ) / 2 );
                QwtPainter::drawLine( painter, pos.x(), y, pos.x() + length, y );
 
                break;
            }
            case QwtScaleDraw::BottomScale:
            {
                const qreal y = qRound( pos.y() + pw / 2 );
                QwtPainter::drawLine( painter, pos.x(), y, pos.x() + length, y );
 
                break;
            }
        }
    }
 
    inline void drawTick( QPainter* painter,
        const QwtScaleDraw* scaleDraw, qreal tickPos, qreal tickLength )
    {
        const QPointF pos = scaleDraw->pos();
        tickPos = qRound( tickPos );
 
        int pw = 0;
        if ( scaleDraw->hasComponent( QwtScaleDraw::Backbone ) )
            pw = qMax( qRound( scaleDraw->penWidthF() ), 1 );
 
        int len = qMax( qRound( tickLength ), 1 );
 
        // the width of ticks at the borders might extent the backbone
        len += pw;
 
        if ( painter->pen().capStyle() == Qt::FlatCap )
            len++; // the end point is not rendered
 
        qreal off = 0.0;
 
        if ( painter->paintEngine()->type() == QPaintEngine::X11 )
        {
            if ( pw == 1 )
            {
                // In opposite to raster, X11 paints the end point
                off = 1.0;
            }
        }
 
        switch ( scaleDraw->alignment() )
        {
            case QwtScaleDraw::LeftScale:
            {
                const qreal x1 = qRound( pos.x() ) + 1;
                const qreal x2 = x1 - len + 1;
 
                QwtPainter::drawLine( painter, x2, tickPos, x1 - off, tickPos );
 
                break;
            }
            case QwtScaleDraw::RightScale:
            {
                const qreal x1 = qRound( pos.x() );
                const qreal x2 = x1 + len - 1;
 
                QwtPainter::drawLine( painter, x1, tickPos, x2 - off, tickPos );
 
                break;
            }
            case QwtScaleDraw::BottomScale:
            {
                const qreal y1 = qRound( pos.y() );
                const qreal y2 = y1 + len - 1;
 
                QwtPainter::drawLine( painter, tickPos, y1, tickPos, y2 - off );
 
                break;
            }
            case QwtScaleDraw::TopScale:
            {
                const qreal y1 = qRound( pos.y() );
                const qreal y2 = y1 - len + 1;
 
                QwtPainter::drawLine( painter, tickPos, y2 + 1, tickPos, y1 + 1 - off );
 
                break;
            }
        }
    }
}
 
class QwtScaleDraw::PrivateData
{
  public:
    PrivateData()
        : len( 0 )
        , alignment( QwtScaleDraw::BottomScale )
        , labelRotation( 0.0 )
    {
    }
 
    QPointF pos;
    double len;
 
    Alignment alignment;
 
    Qt::Alignment labelAlignment;
    double labelRotation;
};
 
QwtScaleDraw::QwtScaleDraw()
{
    m_data = new QwtScaleDraw::PrivateData;
    setLength( 100 );
}
 
QwtScaleDraw::~QwtScaleDraw()
{
    delete m_data;
}
 
QwtScaleDraw::Alignment QwtScaleDraw::alignment() const
{
    return m_data->alignment;
}
 
void QwtScaleDraw::setAlignment( Alignment align )
{
    m_data->alignment = align;
}
 
Qt::Orientation QwtScaleDraw::orientation() const
{
    switch ( m_data->alignment )
    {
        case TopScale:
        case BottomScale:
            return Qt::Horizontal;
        case LeftScale:
        case RightScale:
        default:
            return Qt::Vertical;
    }
}
 
void QwtScaleDraw::getBorderDistHint(
    const QFont& font, int& start, int& end ) const
{
    start = 0;
    end = 1.0;
 
    if ( !hasComponent( QwtAbstractScaleDraw::Labels ) )
        return;
 
    const QList< double >& ticks = scaleDiv().ticks( QwtScaleDiv::MajorTick );
    if ( ticks.count() == 0 )
        return;
 
    // Find the ticks, that are mapped to the borders.
    // minTick is the tick, that is mapped to the top/left-most position
    // in widget coordinates.
 
    double minTick = ticks[0];
    double minPos = scaleMap().transform( minTick );
    double maxTick = minTick;
    double maxPos = minPos;
 
    for ( int i = 1; i < ticks.count(); i++ )
    {
        const double tickPos = scaleMap().transform( ticks[i] );
        if ( tickPos < minPos )
        {
            minTick = ticks[i];
            minPos = tickPos;
        }
        if ( tickPos > scaleMap().transform( maxTick ) )
        {
            maxTick = ticks[i];
            maxPos = tickPos;
        }
    }
 
    double e = 0.0;
    double s = 0.0;
    if ( orientation() == Qt::Vertical )
    {
        s = -labelRect( font, minTick ).top();
        s -= qAbs( minPos - qRound( scaleMap().p2() ) );
 
        e = labelRect( font, maxTick ).bottom();
        e -= qAbs( maxPos - scaleMap().p1() );
    }
    else
    {
        s = -labelRect( font, minTick ).left();
        s -= qAbs( minPos - scaleMap().p1() );
 
        e = labelRect( font, maxTick ).right();
        e -= qAbs( maxPos - scaleMap().p2() );
    }
 
    if ( s < 0.0 )
        s = 0.0;
    if ( e < 0.0 )
        e = 0.0;
 
    start = qwtCeil( s );
    end = qwtCeil( e );
}
 
int QwtScaleDraw::minLabelDist( const QFont& font ) const
{
    if ( !hasComponent( QwtAbstractScaleDraw::Labels ) )
        return 0;
 
    const QList< double >& ticks = scaleDiv().ticks( QwtScaleDiv::MajorTick );
    if ( ticks.isEmpty() )
        return 0;
 
    const QFontMetrics fm( font );
 
    const bool vertical = ( orientation() == Qt::Vertical );
 
    QRectF bRect1;
    QRectF bRect2 = labelRect( font, ticks[0] );
    if ( vertical )
    {
        bRect2.setRect( -bRect2.bottom(), 0.0, bRect2.height(), bRect2.width() );
    }
 
    double maxDist = 0.0;
 
    for ( int i = 1; i < ticks.count(); i++ )
    {
        bRect1 = bRect2;
        bRect2 = labelRect( font, ticks[i] );
        if ( vertical )
        {
            bRect2.setRect( -bRect2.bottom(), 0.0,
                bRect2.height(), bRect2.width() );
        }
 
        double dist = fm.leading(); // space between the labels
        if ( bRect1.right() > 0 )
            dist += bRect1.right();
        if ( bRect2.left() < 0 )
            dist += -bRect2.left();
 
        if ( dist > maxDist )
            maxDist = dist;
    }
 
    double angle = qwtRadians( labelRotation() );
    if ( vertical )
        angle += M_PI / 2;
 
    const double sinA = qFastSin( angle ); // qreal -> double
    if ( qFuzzyCompare( sinA + 1.0, 1.0 ) )
        return qCeil( maxDist );
 
    const int fmHeight = fm.ascent() - 2;
 
    // The distance we need until there is
    // the height of the label font. This height is needed
    // for the neighbored label.
 
    double labelDist = fmHeight / qFastSin( angle ) * qFastCos( angle );
    if ( labelDist < 0 )
        labelDist = -labelDist;
 
    // For text orientations close to the scale orientation
 
    if ( labelDist > maxDist )
        labelDist = maxDist;
 
    // For text orientations close to the opposite of the
    // scale orientation
 
    if ( labelDist < fmHeight )
        labelDist = fmHeight;
 
    return qCeil( labelDist );
}
 
double QwtScaleDraw::extent( const QFont& font ) const
{
    double d = 0;
 
    if ( hasComponent( QwtAbstractScaleDraw::Labels ) )
    {
        if ( orientation() == Qt::Vertical )
            d = maxLabelWidth( font );
        else
            d = maxLabelHeight( font );
 
        if ( d > 0 )
            d += spacing();
    }
 
    if ( hasComponent( QwtAbstractScaleDraw::Ticks ) )
    {
        d += maxTickLength();
    }
 
    if ( hasComponent( QwtAbstractScaleDraw::Backbone ) )
    {
        d += qwtEffectivePenWidth( this );
    }
 
    d = qwtMaxF( d, minimumExtent() );
    return d;
}
 
int QwtScaleDraw::minLength( const QFont& font ) const
{
    int startDist, endDist;
    getBorderDistHint( font, startDist, endDist );
 
    const QwtScaleDiv& sd = scaleDiv();
 
    const uint minorCount =
        sd.ticks( QwtScaleDiv::MinorTick ).count() +
        sd.ticks( QwtScaleDiv::MediumTick ).count();
    const uint majorCount =
        sd.ticks( QwtScaleDiv::MajorTick ).count();
 
    int lengthForLabels = 0;
    if ( hasComponent( QwtAbstractScaleDraw::Labels ) )
        lengthForLabels = minLabelDist( font ) * majorCount;
 
    int lengthForTicks = 0;
    if ( hasComponent( QwtAbstractScaleDraw::Ticks ) )
    {
        const double pw = qwtEffectivePenWidth( this );
        lengthForTicks = qCeil( ( majorCount + minorCount ) * ( pw + 1.0 ) );
    }
 
    return startDist + endDist + qMax( lengthForLabels, lengthForTicks );
}
 
QPointF QwtScaleDraw::labelPosition( double value ) const
{
    const double tval = scaleMap().transform( value );
    double dist = spacing();
    if ( hasComponent( QwtAbstractScaleDraw::Backbone ) )
        dist += qwtEffectivePenWidth( this );
 
    if ( hasComponent( QwtAbstractScaleDraw::Ticks ) )
        dist += tickLength( QwtScaleDiv::MajorTick );
 
    double px = 0;
    double py = 0;
 
    switch ( alignment() )
    {
        case RightScale:
        {
            px = m_data->pos.x() + dist;
            py = tval;
            break;
        }
        case LeftScale:
        {
            px = m_data->pos.x() - dist;
            py = tval;
            break;
        }
        case BottomScale:
        {
            px = tval;
            py = m_data->pos.y() + dist;
            break;
        }
        case TopScale:
        {
            px = tval;
            py = m_data->pos.y() - dist;
            break;
        }
    }
 
    return QPointF( px, py );
}
 
void QwtScaleDraw::drawTick( QPainter* painter, double value, double len ) const
{
    if ( len <= 0 )
        return;
 
    const double tval = scaleMap().transform( value );
 
    if ( QwtPainter::roundingAlignment( painter ) )
        QwtScaleRendererInt::drawTick( painter, this, tval, len );
    else
        QwtScaleRendererReal::drawTick( painter, this, tval, len );
}
 
void QwtScaleDraw::drawBackbone( QPainter* painter ) const
{
    if ( QwtPainter::roundingAlignment( painter ) )
        QwtScaleRendererInt::drawBackbone( painter, this );
    else
        QwtScaleRendererReal::drawBackbone( painter, this );
}
 
void QwtScaleDraw::move( const QPointF& pos )
{
    m_data->pos = pos;
    updateMap();
}
 
QPointF QwtScaleDraw::pos() const
{
    return m_data->pos;
}
 
void QwtScaleDraw::setLength( double length )
{
    if ( length >= 0 && length < 10 )
        length = 10;
 
    // f.e the left/bottom scales of a polar plot
    if ( length < 0 && length > -10 )
        length = -10;
 
    m_data->len = length;
    updateMap();
}
 
double QwtScaleDraw::length() const
{
    return m_data->len;
}
 
void QwtScaleDraw::drawLabel( QPainter* painter, double value ) const
{
    QwtText lbl = tickLabel( painter->font(), value );
    if ( lbl.isEmpty() )
        return;
 
    QPointF pos = labelPosition( value );
 
    QSizeF labelSize = lbl.textSize( painter->font() );
 
    const QTransform transform = labelTransformation( pos, labelSize );
 
    painter->save();
    painter->setWorldTransform( transform, true );
 
    lbl.draw ( painter, QRect( QPoint( 0, 0 ), labelSize.toSize() ) );
 
    painter->restore();
}
 
QRect QwtScaleDraw::boundingLabelRect( const QFont& font, double value ) const
{
    QwtText lbl = tickLabel( font, value );
    if ( lbl.isEmpty() )
        return QRect();
 
    const QPointF pos = labelPosition( value );
    QSizeF labelSize = lbl.textSize( font );
 
    const QTransform transform = labelTransformation( pos, labelSize );
    return transform.mapRect( QRect( QPoint( 0, 0 ), labelSize.toSize() ) );
}
 
QTransform QwtScaleDraw::labelTransformation(
    const QPointF& pos, const QSizeF& size ) const
{
    QTransform transform;
    transform.translate( pos.x(), pos.y() );
    transform.rotate( labelRotation() );
 
    int flags = labelAlignment();
    if ( flags == 0 )
    {
        switch ( alignment() )
        {
            case RightScale:
            {
                if ( flags == 0 )
                    flags = Qt::AlignRight | Qt::AlignVCenter;
                break;
            }
            case LeftScale:
            {
                if ( flags == 0 )
                    flags = Qt::AlignLeft | Qt::AlignVCenter;
                break;
            }
            case BottomScale:
            {
                if ( flags == 0 )
                    flags = Qt::AlignHCenter | Qt::AlignBottom;
                break;
            }
            case TopScale:
            {
                if ( flags == 0 )
                    flags = Qt::AlignHCenter | Qt::AlignTop;
                break;
            }
        }
    }
 
    double x, y;
 
    if ( flags & Qt::AlignLeft )
        x = -size.width();
    else if ( flags & Qt::AlignRight )
        x = 0.0;
    else // Qt::AlignHCenter
        x = -( 0.5 * size.width() );
 
    if ( flags & Qt::AlignTop )
        y = -size.height();
    else if ( flags & Qt::AlignBottom )
        y = 0;
    else // Qt::AlignVCenter
        y = -( 0.5 * size.height() );
 
    transform.translate( x, y );
 
    return transform;
}
 
QRectF QwtScaleDraw::labelRect( const QFont& font, double value ) const
{
    QwtText lbl = tickLabel( font, value );
    if ( lbl.isEmpty() )
        return QRectF( 0.0, 0.0, 0.0, 0.0 );
 
    const QPointF pos = labelPosition( value );
 
    const QSizeF labelSize = lbl.textSize( font );
    const QTransform transform = labelTransformation( pos, labelSize );
 
    QRectF br = transform.mapRect( QRectF( QPointF( 0, 0 ), labelSize ) );
    br.translate( -pos.x(), -pos.y() );
 
    return br;
}
 
QSizeF QwtScaleDraw::labelSize( const QFont& font, double value ) const
{
    return labelRect( font, value ).size();
}
 
void QwtScaleDraw::setLabelRotation( double rotation )
{
    m_data->labelRotation = rotation;
}
 
double QwtScaleDraw::labelRotation() const
{
    return m_data->labelRotation;
}
 
void QwtScaleDraw::setLabelAlignment( Qt::Alignment alignment )
{
    m_data->labelAlignment = alignment;
}
 
Qt::Alignment QwtScaleDraw::labelAlignment() const
{
    return m_data->labelAlignment;
}
 
int QwtScaleDraw::maxLabelWidth( const QFont& font ) const
{
    double maxWidth = 0.0;
 
    const QList< double >& ticks = scaleDiv().ticks( QwtScaleDiv::MajorTick );
    for ( int i = 0; i < ticks.count(); i++ )
    {
        const double v = ticks[i];
        if ( scaleDiv().contains( v ) )
        {
            const double w = labelSize( font, ticks[i] ).width();
            if ( w > maxWidth )
                maxWidth = w;
        }
    }
 
    return qCeil( maxWidth );
}
 
int QwtScaleDraw::maxLabelHeight( const QFont& font ) const
{
    double maxHeight = 0.0;
 
    const QList< double >& ticks = scaleDiv().ticks( QwtScaleDiv::MajorTick );
    for ( int i = 0; i < ticks.count(); i++ )
    {
        const double v = ticks[i];
        if ( scaleDiv().contains( v ) )
        {
            const double h = labelSize( font, ticks[i] ).height();
            if ( h > maxHeight )
                maxHeight = h;
        }
    }
 
    return qCeil( maxHeight );
}
 
void QwtScaleDraw::updateMap()
{
    const QPointF pos = m_data->pos;
    double len = m_data->len;
 
    QwtScaleMap& sm = scaleMap();
    if ( orientation() == Qt::Vertical )
        sm.setPaintInterval( pos.y() + len, pos.y() );
    else
        sm.setPaintInterval( pos.x(), pos.x() + len );
}