qwt_slider.cpp

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/* -*- 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_slider.h"
#include "qwt_painter.h"
#include "qwt_scale_draw.h"
#include "qwt_scale_map.h"
#include <qevent.h>
#include <qdrawutil.h>
#include <qpainter.h>
#include <qalgorithms.h>
#include <qmath.h>
#include <qstyle.h>
#include <qstyleoption.h>
#include <qapplication.h>

static QSize qwtHandleSize( const QSize &size, 
    Qt::Orientation orientation, bool hasTrough )
{
    QSize handleSize = size;

    if ( handleSize.isEmpty() )
    {
        const int handleThickness = 16;
        handleSize.setWidth( 2 * handleThickness );
        handleSize.setHeight( handleThickness );

        if ( !hasTrough )
            handleSize.transpose();

        if ( orientation == Qt::Vertical )
            handleSize.transpose();
    }

    return handleSize;
}

static QwtScaleDraw::Alignment qwtScaleDrawAlignment( 
    Qt::Orientation orientation, QwtSlider::ScalePosition scalePos )
{
    QwtScaleDraw::Alignment align;

    if ( orientation == Qt::Vertical )
    {
        // NoScale lays out like Left
        if ( scalePos == QwtSlider::LeadingScale )
            align = QwtScaleDraw::RightScale;
        else
            align = QwtScaleDraw::LeftScale;
    }
    else
    {
        // NoScale lays out like Bottom
        if ( scalePos == QwtSlider::TrailingScale )
            align = QwtScaleDraw::TopScale;
        else
            align = QwtScaleDraw::BottomScale;
    }

    return align;
}

class QwtSlider::PrivateData
{
public:
    PrivateData():
        repeatTimerId( 0 ),
        updateInterval( 150 ),
        stepsIncrement( 0 ),
        pendingValueChange( false ),
        borderWidth( 2 ),
        spacing( 4 ),
        scalePosition( QwtSlider::TrailingScale ),
        hasTrough( true ),
        hasGroove( false ),
        mouseOffset( 0 )
    {
    }

    int repeatTimerId;
    bool timerTick;
    int updateInterval;
    int stepsIncrement;
    bool pendingValueChange;

    QRect sliderRect;

    QSize handleSize;
    int borderWidth;
    int spacing;

    Qt::Orientation orientation;
    QwtSlider::ScalePosition scalePosition;

    bool hasTrough;
    bool hasGroove;

    int mouseOffset;

    mutable QSize sizeHintCache;
};
QwtSlider::QwtSlider( QWidget *parent ):
    QwtAbstractSlider( parent )
{
    initSlider( Qt::Vertical );
}

QwtSlider::QwtSlider( Qt::Orientation orientation, QWidget *parent ):
    QwtAbstractSlider( parent )
{
    initSlider( orientation );
}

QwtSlider::~QwtSlider()
{
    delete d_data;
}

void QwtSlider::initSlider( Qt::Orientation orientation )
{
    if ( orientation == Qt::Vertical )
        setSizePolicy( QSizePolicy::Fixed, QSizePolicy::Expanding );
    else
        setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Fixed );

    setAttribute( Qt::WA_WState_OwnSizePolicy, false );

    d_data = new QwtSlider::PrivateData;

    d_data->orientation = orientation;

    scaleDraw()->setAlignment( 
        qwtScaleDrawAlignment( orientation, d_data->scalePosition ) );
    scaleDraw()->setLength( 100 );

    setScale( 0.0, 100.0 );
    setValue( 0.0 );
}

void QwtSlider::setOrientation( Qt::Orientation orientation )
{
    if ( orientation == d_data->orientation )
        return;

    d_data->orientation = orientation;

    scaleDraw()->setAlignment( 
        qwtScaleDrawAlignment( orientation, d_data->scalePosition ) );

    if ( !testAttribute( Qt::WA_WState_OwnSizePolicy ) )
    {
        QSizePolicy sp = sizePolicy();
        sp.transpose();
        setSizePolicy( sp );

        setAttribute( Qt::WA_WState_OwnSizePolicy, false );
    }

    if ( testAttribute( Qt::WA_WState_Polished ) )
        layoutSlider( true );
}

Qt::Orientation QwtSlider::orientation() const
{
    return d_data->orientation;
}

void QwtSlider::setScalePosition( ScalePosition scalePosition )
{
    if ( d_data->scalePosition == scalePosition )
        return;

    d_data->scalePosition = scalePosition;
    scaleDraw()->setAlignment( 
        qwtScaleDrawAlignment( d_data->orientation, scalePosition ) );

    if ( testAttribute( Qt::WA_WState_Polished ) )
        layoutSlider( true );
}

QwtSlider::ScalePosition QwtSlider::scalePosition() const
{
    return d_data->scalePosition;
}

void QwtSlider::setBorderWidth( int width )
{
    if ( width < 0 )
        width = 0;

    if ( width != d_data->borderWidth )
    {
        d_data->borderWidth = width;

        if ( testAttribute( Qt::WA_WState_Polished ) )
            layoutSlider( true );
    }
}

int QwtSlider::borderWidth() const
{
    return d_data->borderWidth;
}

void QwtSlider::setSpacing( int spacing )
{
    if ( spacing <= 0 )
        spacing = 0;

    if ( spacing != d_data->spacing  )
    {
        d_data->spacing = spacing;

        if ( testAttribute( Qt::WA_WState_Polished ) )
            layoutSlider( true );
    }
}

int QwtSlider::spacing() const
{
    return d_data->spacing;
}

void QwtSlider::setHandleSize( const QSize &size )
{
    if ( size != d_data->handleSize )
    {
        d_data->handleSize = size;

        if ( testAttribute( Qt::WA_WState_Polished ) )
            layoutSlider( true );
    }
}

QSize QwtSlider::handleSize() const
{
    return d_data->handleSize;
}

void QwtSlider::setScaleDraw( QwtScaleDraw *scaleDraw )
{
    const QwtScaleDraw *previousScaleDraw = this->scaleDraw();
    if ( scaleDraw == NULL || scaleDraw == previousScaleDraw )
        return;

    if ( previousScaleDraw )
        scaleDraw->setAlignment( previousScaleDraw->alignment() );

    setAbstractScaleDraw( scaleDraw );

    if ( testAttribute( Qt::WA_WState_Polished ) )
        layoutSlider( true );
}

const QwtScaleDraw *QwtSlider::scaleDraw() const
{
    return static_cast<const QwtScaleDraw *>( abstractScaleDraw() );
}

QwtScaleDraw *QwtSlider::scaleDraw()
{
    return static_cast<QwtScaleDraw *>( abstractScaleDraw() );
}

void QwtSlider::scaleChange()
{
    QwtAbstractSlider::scaleChange();

    if ( testAttribute( Qt::WA_WState_Polished ) )
        layoutSlider( true );
}

void QwtSlider::setUpdateInterval( int interval )
{
    d_data->updateInterval = qMax( interval, 50 );
}

int QwtSlider::updateInterval() const
{
    return d_data->updateInterval;
}

void QwtSlider::drawSlider( 
    QPainter *painter, const QRect &sliderRect ) const
{
    QRect innerRect( sliderRect );

    if ( d_data->hasTrough )
    {
        const int bw = d_data->borderWidth;
        innerRect = sliderRect.adjusted( bw, bw, -bw, -bw );

        painter->fillRect( innerRect, palette().brush( QPalette::Mid ) );
        qDrawShadePanel( painter, sliderRect, palette(), true, bw, NULL );
    }

    if ( d_data->hasGroove )
    {
        const QSize handleSize = qwtHandleSize( d_data->handleSize,
            d_data->orientation, d_data->hasTrough );

        const int slotExtent = 4;
        const int slotMargin = 4;

        QRect slotRect; 
        if ( orientation() == Qt::Horizontal )
        {
            int slotOffset = qMax( 1, handleSize.width() / 2 - slotMargin );
            int slotHeight = slotExtent + ( innerRect.height() % 2 );

            slotRect.setWidth( innerRect.width() - 2 * slotOffset );
            slotRect.setHeight( slotHeight );
        }
        else
        {
            int slotOffset = qMax( 1, handleSize.height() / 2 - slotMargin );
            int slotWidth = slotExtent + ( innerRect.width() % 2 );

            slotRect.setWidth( slotWidth );
            slotRect.setHeight( innerRect.height() - 2 * slotOffset );

        }

        slotRect.moveCenter( innerRect.center() );

        QBrush brush = palette().brush( QPalette::Dark );
        qDrawShadePanel( painter, slotRect, palette(), true, 1 , &brush );
    }

    if ( isValid() )
        drawHandle( painter, handleRect(), transform( value() ) );
}

void QwtSlider::drawHandle( QPainter *painter, 
    const QRect &handleRect, int pos ) const
{
    const int bw = d_data->borderWidth;

    qDrawShadePanel( painter, 
        handleRect, palette(), false, bw,
        &palette().brush( QPalette::Button ) );

    pos++; // shade line points one pixel below
    if ( orientation() == Qt::Horizontal )
    {
        qDrawShadeLine( painter, pos, handleRect.top() + bw,
            pos, handleRect.bottom() - bw, palette(), true, 1 );
    }
    else // Vertical
    {
        qDrawShadeLine( painter, handleRect.left() + bw, pos,
            handleRect.right() - bw, pos, palette(), true, 1 );
    }
}

bool QwtSlider::isScrollPosition( const QPoint &pos ) const
{
    if ( handleRect().contains( pos ) )
    {
        const double v = ( orientation() == Qt::Horizontal ) 
            ? pos.x() : pos.y();

        d_data->mouseOffset = v - transform( value() );
        return true;
    }

    return false;
}

double QwtSlider::scrolledTo( const QPoint &pos ) const
{
    int p = ( orientation() == Qt::Horizontal ) 
        ? pos.x() : pos.y();

    p -= d_data->mouseOffset;

    int min = transform( lowerBound() );
    int max = transform( upperBound() );
    if ( min > max )
        qSwap( min, max );

    p = qBound( min, p, max );

    return scaleMap().invTransform( p );
}

void QwtSlider::mousePressEvent( QMouseEvent *event )
{
    if ( isReadOnly() )
    {
        event->ignore();
        return;
    }

    const QPoint pos = event->pos();

    if ( isValid() && d_data->sliderRect.contains( pos ) )
    {
        if ( !handleRect().contains( pos ) )
        {
            const int markerPos = transform( value() );

            d_data->stepsIncrement = pageSteps();

            if ( d_data->orientation == Qt::Horizontal )
            {
                if ( pos.x() < markerPos )
                    d_data->stepsIncrement = -d_data->stepsIncrement;
            }
            else
            {
                if ( pos.y() < markerPos )
                    d_data->stepsIncrement = -d_data->stepsIncrement;
            }

            if ( isInverted() )
                d_data->stepsIncrement = -d_data->stepsIncrement;

            const double v = value();
            incrementValue( d_data->stepsIncrement );

            if ( v != value() )
            {
                if ( isTracking() )
                    Q_EMIT valueChanged( value() );
                else
                    d_data->pendingValueChange = true;

                Q_EMIT sliderMoved( value() );
            }

            d_data->timerTick = false;
            d_data->repeatTimerId = startTimer( qMax( 250, 2 * updateInterval() ) );

            return;
        }
    }

    QwtAbstractSlider::mousePressEvent( event );
}

void QwtSlider::mouseReleaseEvent( QMouseEvent *event )
{
    if ( d_data->repeatTimerId > 0 )
    {
        killTimer( d_data->repeatTimerId );
        d_data->repeatTimerId = 0;
        d_data->timerTick = false;
        d_data->stepsIncrement = 0;
    }

    if ( d_data->pendingValueChange )
    {
        d_data->pendingValueChange = false;
        Q_EMIT valueChanged( value() );
    }

    QwtAbstractSlider::mouseReleaseEvent( event );
}

void QwtSlider::timerEvent( QTimerEvent *event )
{
    if ( event->timerId() != d_data->repeatTimerId )
    {
        QwtAbstractSlider::timerEvent( event );
        return;
    }

    if ( !isValid() )
    {
        killTimer( d_data->repeatTimerId );
        d_data->repeatTimerId = 0;
        return;
    }

    const double v = value();
    incrementValue( d_data->stepsIncrement );

    if ( v != value() )
    {
        if ( isTracking() )
            Q_EMIT valueChanged( value() );
        else
            d_data->pendingValueChange = true;

        Q_EMIT sliderMoved( value() );
    }

    if ( !d_data->timerTick )
    {
        // restart the timer with a shorter interval
        killTimer( d_data->repeatTimerId );
        d_data->repeatTimerId = startTimer( updateInterval() );
        
        d_data->timerTick = true;
    }   
}

void QwtSlider::paintEvent( QPaintEvent *event )
{
    QPainter painter( this );
    painter.setClipRegion( event->region() );

    QStyleOption opt;
    opt.init(this);
    style()->drawPrimitive(QStyle::PE_Widget, &opt, &painter, this);

    if ( d_data->scalePosition != QwtSlider::NoScale )
    {
        if ( !d_data->sliderRect.contains( event->rect() ) )
            scaleDraw()->draw( &painter, palette() );
    }

    drawSlider( &painter, d_data->sliderRect );

    if ( hasFocus() )
        QwtPainter::drawFocusRect( &painter, this, d_data->sliderRect );
}

void QwtSlider::resizeEvent( QResizeEvent *event )
{
    layoutSlider( false );
    QwtAbstractSlider::resizeEvent( event );
}

bool QwtSlider::event( QEvent *event )
{
    if ( event->type() == QEvent::PolishRequest )
        layoutSlider( false );

    return QwtAbstractSlider::event( event );
}

void QwtSlider::changeEvent( QEvent *event )
{
    if ( event->type() == QEvent::StyleChange || 
        event->type() == QEvent::FontChange )
    {
        if ( testAttribute( Qt::WA_WState_Polished ) )
            layoutSlider( true );
    }

    QwtAbstractSlider::changeEvent( event );
}

void QwtSlider::layoutSlider( bool update_geometry )
{
    int bw = 0;
    if ( d_data->hasTrough )
        bw = d_data->borderWidth;

    const QSize handleSize = qwtHandleSize( d_data->handleSize,
        d_data->orientation, d_data->hasTrough );

    QRect sliderRect = contentsRect();

    /*
       The marker line of the handle needs to be aligned to
       the scale. But the marker is in the center 
       and we need space enough to display the rest of the handle.

       But the scale itself usually needs margins for displaying
       the tick labels, that also might needs space beyond the
       backbone.

       Now it depends on what needs more margins. If it is the
       slider the scale gets shrunk, otherwise the slider.
     */

    int scaleMargin = 0;
    if ( d_data->scalePosition != QwtSlider::NoScale )
    {
        int d1, d2;
        scaleDraw()->getBorderDistHint( font(), d1, d2 );

        scaleMargin = qMax( d1, d2 ) - bw;
    }

    int scaleX, scaleY, scaleLength;

    if ( d_data->orientation == Qt::Horizontal )
    {
        const int handleMargin = handleSize.width() / 2 - 1;
        if ( scaleMargin > handleMargin )
        {
            int off = scaleMargin - handleMargin;
            sliderRect.adjust( off, 0, -off, 0 );
        }

        scaleX = sliderRect.left() + bw + handleSize.width() / 2 - 1;
        scaleLength = sliderRect.width() - handleSize.width();
    }
    else
    {
        int handleMargin = handleSize.height() / 2 - 1;
        if ( scaleMargin > handleMargin )
        {
            int off = scaleMargin - handleMargin;
            sliderRect.adjust( 0, off, 0, -off );
        }

        scaleY = sliderRect.top() + bw + handleSize.height() / 2 - 1;
        scaleLength = sliderRect.height() - handleSize.height();
    }

    scaleLength -= 2 * bw;

    // now align slider and scale according to the ScalePosition

    if ( d_data->orientation == Qt::Horizontal )
    {
        const int h = handleSize.height() + 2 * bw;

        if ( d_data->scalePosition == QwtSlider::TrailingScale )
        {
            sliderRect.setTop( sliderRect.bottom() + 1 - h );
            scaleY = sliderRect.top() - d_data->spacing;
        }
        else
        {
            sliderRect.setHeight( h );
            scaleY = sliderRect.bottom() + 1 + d_data->spacing;
        }
    }
    else // Qt::Vertical
    {
        const int w = handleSize.width() + 2 * bw;

        if ( d_data->scalePosition == QwtSlider::LeadingScale )
        {
            sliderRect.setWidth( w );
            scaleX = sliderRect.right() + 1 + d_data->spacing;
        }
        else
        {
            sliderRect.setLeft( sliderRect.right() + 1 - w );
            scaleX = sliderRect.left() - d_data->spacing;
        }
    }

    d_data->sliderRect = sliderRect;

    scaleDraw()->move( scaleX, scaleY );
    scaleDraw()->setLength( scaleLength );

    if ( update_geometry )
    {
        d_data->sizeHintCache = QSize(); // invalidate
        updateGeometry();
        update();
    }
}

void QwtSlider::setTrough( bool on )
{
    if ( d_data->hasTrough != on )
    {
        d_data->hasTrough = on;

        if ( testAttribute( Qt::WA_WState_Polished ) )
            layoutSlider( true );
    }
}

bool QwtSlider::hasTrough() const
{
    return d_data->hasTrough;
}

void QwtSlider::setGroove( bool on )
{
    if ( d_data->hasGroove != on )
    {
        d_data->hasGroove = on;
        
        if ( testAttribute( Qt::WA_WState_Polished ) )
            layoutSlider( true );
    }
}

bool QwtSlider::hasGroove() const
{
    return d_data->hasGroove;
} 

QSize QwtSlider::sizeHint() const
{
    const QSize hint = minimumSizeHint();
    return hint.expandedTo( QApplication::globalStrut() );
}

QSize QwtSlider::minimumSizeHint() const
{
    if ( !d_data->sizeHintCache.isEmpty() )
        return d_data->sizeHintCache;

    const QSize handleSize = qwtHandleSize( d_data->handleSize,
        d_data->orientation, d_data->hasTrough );

    int bw = 0;
    if ( d_data->hasTrough )
        bw = d_data->borderWidth;

    int sliderLength = 0; 
    int scaleExtent = 0;

    if ( d_data->scalePosition != QwtSlider::NoScale )
    {
        int d1, d2;
        scaleDraw()->getBorderDistHint( font(), d1, d2 );

        const int scaleBorderDist = 2 * ( qMax( d1, d2 ) - bw );

        int handleBorderDist;
        if ( d_data->orientation == Qt::Horizontal )
            handleBorderDist = handleSize.width();
        else
            handleBorderDist = handleSize.height();

        sliderLength = scaleDraw()->minLength( font() );
        if ( handleBorderDist > scaleBorderDist )
        {
            // We need additional space for the overlapping handle
            sliderLength += handleBorderDist - scaleBorderDist;
        }

        scaleExtent += d_data->spacing;
        scaleExtent += qCeil( scaleDraw()->extent( font() ) );
    }

    sliderLength = qMax( sliderLength, 84 ); // from QSlider

    int w = 0;
    int h = 0;

    if ( d_data->orientation == Qt::Horizontal )
    {
        w = sliderLength;
        h = handleSize.height() + 2 * bw + scaleExtent;
    }
    else
    {
        w = handleSize.width() + 2 * bw + scaleExtent;
        h = sliderLength;
    }

    // finally add margins
    int left, right, top, bottom;
    getContentsMargins( &left, &top, &right, &bottom );

    w += left + right;
    h += top + bottom;

    d_data->sizeHintCache = QSize( w, h );
    return d_data->sizeHintCache;
}

QRect QwtSlider::handleRect() const
{
    if ( !isValid() )
        return QRect();

    const int markerPos = transform( value() );

    QPoint center = d_data->sliderRect.center();
    if ( d_data->orientation == Qt::Horizontal )
        center.setX( markerPos );
    else
        center.setY( markerPos );

    QRect rect;
    rect.setSize( qwtHandleSize( d_data->handleSize,
        d_data->orientation, d_data->hasTrough ) );
    rect.moveCenter( center );

    return rect;
}

QRect QwtSlider::sliderRect() const
{
    return d_data->sliderRect;
}