source: trunk/src/widgets/qslider.cpp

/****************************************************************************
** $Id: qslider.cpp 174 2007-11-06 22:27:57Z dmik $
**
** Implementation of QSlider class
**
** Created : 961019
**
** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of the widgets module of the Qt GUI Toolkit.
**
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** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.QPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** Licensees holding valid Qt Enterprise Edition or Qt Professional Edition
** licenses may use this file in accordance with the Qt Commercial License
** Agreement provided with the Software.
**
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** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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**   information about Qt Commercial License Agreements.
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**********************************************************************/

#include "qslider.h"
#ifndef QT_NO_SLIDER
#include "qpainter.h"
#include "qdrawutil.h"
#include "qtimer.h"
#include "qbitmap.h"
#include "qapplication.h"
#include "qstyle.h"
#if defined(QT_ACCESSIBILITY_SUPPORT)
#include "qaccessible.h"
#endif

static const int thresholdTime = 300;
static const int repeatTime = 100;

struct QSliderPrivate
{
    // ### move these to QSlider in Qt 4.0
    int sliderStartVal;
    QSliderPrivate() : sliderStartVal( 0 ) { }
};


/*!
    \class QSlider
    \brief The QSlider widget provides a vertical or horizontal slider.

    \ingroup basic
    \mainclass

    The slider is the classic widget for controlling a bounded value.
    It lets the user move a slider along a horizontal or vertical
    groove and translates the slider's position into an integer value
    within the legal range.

    QSlider inherits QRangeControl, which provides the "integer" side
    of the slider. setRange() and value() are likely to be used by
    practically all slider users; see the \l QRangeControl
    documentation for information about the many other functions that
    class provides.

    The main functions offered by the slider itself are tickmark and
    orientation control; you can use setTickmarks() to indicate where
    you want the tickmarks to be, setTickInterval() to indicate how
    many of them you want and setOrientation() to indicate whether the
    slider is to be horizontal or vertical.

    A slider accepts focus on Tab and uses the mouse wheel and a
    suitable keyboard interface.

    <img src=qslider-m.png> <img src=qslider-w.png>

    \important setRange

    \sa QScrollBar QSpinBox
    \link guibooks.html#fowler GUI Design Handbook: Slider\endlink
*/


/*!
    \enum QSlider::TickSetting

    This enum specifies where the tickmarks are to be drawn relative
    to the slider's groove and the handle the user moves.

    \value NoMarks do not draw any tickmarks.
    \value Both draw tickmarks on both sides of the groove.
    \value Above draw tickmarks above the (horizontal) slider
    \value Below draw tickmarks below the (horizontal) slider
    \value Left draw tickmarks to the left of the (vertical) slider
    \value Right draw tickmarks to the right of the (vertical) slider
*/


/*!
    Constructs a vertical slider.

    The \a parent and \a name arguments are sent on to the QWidget
    constructor.
*/

QSlider::QSlider( QWidget *parent, const char *name )
    : QWidget( parent, name  )
{
    orient = Vertical;
    init();
}

/*!
    Constructs a slider.

    The \a orientation must be \l Qt::Vertical or \l Qt::Horizontal.

    The \a parent and \a name arguments are sent on to the QWidget
    constructor.
*/

QSlider::QSlider( Orientation orientation, QWidget *parent, const char *name )
    : QWidget( parent, name )
{
    orient = orientation;
    init();
}

/*!
    Constructs a slider whose value can never be smaller than \a
    minValue or greater than \a maxValue, whose page step size is \a
    pageStep and whose value is initially \a value (which is
    guaranteed to be in range using bound()).

    If \a orientation is \c Qt::Vertical the slider is vertical and if it
    is \c Qt::Horizontal the slider is horizontal.

    The \a parent and \a name arguments are sent on to the QWidget
    constructor.
*/

QSlider::QSlider( int minValue, int maxValue, int pageStep,
                  int value, Orientation orientation,
                  QWidget *parent, const char *name )
    : QWidget( parent, name ),
      QRangeControl( minValue, maxValue, 1, pageStep, value )
{
    orient = orientation;
    init();
    sliderVal = value;
}

/*!
    Destructor.
*/
QSlider::~QSlider()
{
    delete d;
}

void QSlider::init()
{
    d = new QSliderPrivate;
    timer = 0;
    sliderPos = 0;
    sliderVal = 0;
    clickOffset = 0;
    state = Idle;
    track = TRUE;
    ticks = NoMarks;
    tickInt = 0;

    if ( style().styleHint( QStyle::SH_GUIStyle ) == QStyle::PMStyle )
        setFocusPolicy( StrongFocus );
    else
    setFocusPolicy( TabFocus  );
    initTicks();

    QSizePolicy sp( QSizePolicy::Expanding, QSizePolicy::Fixed );
    if ( orient == Vertical )
        sp.transpose();
    setSizePolicy( sp );
    clearWState( WState_OwnSizePolicy );
}


/*
    Does what's needed when someone changes the tickmark status.
*/

void QSlider::initTicks()
{
    tickOffset = style().pixelMetric( QStyle::PM_SliderTickmarkOffset, this );
}


/*!
    \property QSlider::tracking
    \brief whether slider tracking is enabled

    If tracking is enabled (the default), the slider emits the
    valueChanged() signal whenever the slider is being dragged. If
    tracking is disabled, the slider emits the valueChanged() signal
    when the user releases the mouse button (unless the value happens
    to be the same as before).
*/

void QSlider::setTracking( bool enable )
{
    track = enable;
}


/*!
    \fn void QSlider::valueChanged( int value )

    This signal is emitted when the slider value is changed, with the
    new slider \a value as its argument.
*/

/*!
    \fn void QSlider::sliderPressed()

    This signal is emitted when the user presses the slider with the
    mouse.
*/

/*!
    \fn void QSlider::sliderMoved( int value )

    This signal is emitted when the slider is dragged, with the new
    slider \a value as its argument.
*/

/*!
    \fn void QSlider::sliderReleased()

    This signal is emitted when the user releases the slider with the mouse.
*/

/*
    Calculates slider position corresponding to value \a v.
*/

int QSlider::positionFromValue( int v ) const
{
    int  a = available();
    int x = QRangeControl::positionFromValue( v, a );
    if ( orient == Horizontal && QApplication::reverseLayout() )
        x = a - x;
    return x;
}

/*
    Returns the available space in which the slider can move.
*/

int QSlider::available() const
{
    return style().pixelMetric( QStyle::PM_SliderSpaceAvailable, this );
}

/*
    Calculates a value corresponding to slider position \a p.
*/

int QSlider::valueFromPosition( int p ) const
{
    int a = available();
    int x = QRangeControl::valueFromPosition( p, a );
    if ( orient == Horizontal && QApplication::reverseLayout() )
        x = maxValue() + minValue() - x;
    return x;
}

/*!
    Implements the virtual QRangeControl function.
*/

void QSlider::rangeChange()
{
    int newPos = positionFromValue( value() );
    if ( newPos != sliderPos ) {
        reallyMoveSlider( newPos );
    }
}

/*!
    Implements the virtual QRangeControl function.
*/

void QSlider::valueChange()
{
    if ( sliderVal != value() ) {
        int newPos = positionFromValue( value() );
        sliderVal = value();
        reallyMoveSlider( newPos );
    }
    emit valueChanged(value());
#if defined(QT_ACCESSIBILITY_SUPPORT)
    QAccessible::updateAccessibility( this, 0, QAccessible::ValueChanged );
#endif
}


/*!
    \reimp
*/
void QSlider::resizeEvent( QResizeEvent * )
{
    rangeChange();
    initTicks();
}


/*!
    Reimplements the virtual function QWidget::setPalette().

    Sets the background color to the mid color for Motif style sliders
    using palette \a p.
*/

void QSlider::setPalette( const QPalette &p )
{
    QWidget::setPalette( p );
}



/*!
    \property QSlider::orientation
    \brief the slider's orientation

    The orientation must be \l Qt::Vertical (the default) or \l
    Qt::Horizontal.
*/

void QSlider::setOrientation( Orientation orientation )
{
    if ( orientation == orient )
        return;

    if ( !testWState( WState_OwnSizePolicy ) ) {
        QSizePolicy sp = sizePolicy();
        sp.transpose();
        setSizePolicy( sp );
        clearWState( WState_OwnSizePolicy );
    }

    orient = orientation;

    rangeChange();
    update();
}

/*!
    \fn int QSlider::sliderStart() const

    Returns the start position of the slider.
*/


/*!
    Returns the slider handle rectangle. (This is the visual marker
    that the user can move.)
*/

QRect QSlider::sliderRect() const
{
    return style().querySubControlMetrics( QStyle::CC_Slider, this,
                                           QStyle::SC_SliderHandle );
}

/*
    Performs the actual moving of the slider.
*/

void QSlider::reallyMoveSlider( int newPos )
{
    QRegion oldR(sliderRect());
    sliderPos = newPos;
    QRegion newR(sliderRect());

    /* just the one repaint if no background */
    if (backgroundMode() == NoBackground)
        repaint(newR | oldR, FALSE);
    else {
        repaint(oldR.subtract(newR));
        repaint(newR, FALSE);
    }
}


/*!
    \reimp
*/
void QSlider::paintEvent( QPaintEvent * )
{
    QPainter p( this );

    QStyle::SFlags flags = QStyle::Style_Default;
    if (isEnabled())
        flags |= QStyle::Style_Enabled;
    if (hasFocus())
        flags |= QStyle::Style_HasFocus;

    QStyle::SCFlags sub = QStyle::SC_SliderGroove | QStyle::SC_SliderHandle;
    if ( tickmarks() != NoMarks )
        sub |= QStyle::SC_SliderTickmarks;

    style().drawComplexControl( QStyle::CC_Slider, &p, this, rect(), colorGroup(),
                                flags, sub, state == Dragging ? QStyle::SC_SliderHandle : QStyle::SC_None );
}


/*!
    \reimp
*/
void QSlider::mousePressEvent( QMouseEvent *e )
{
    int slideLength = style().pixelMetric( QStyle::PM_SliderLength, this );
    resetState();
    d->sliderStartVal = sliderVal;
    QRect r = sliderRect();

    if ( e->button() == RightButton )
        return;

    if ( r.contains( e->pos() ) ) {
        state = Dragging;
        clickOffset = (QCOORD)( goodPart( e->pos() ) - sliderPos );
        emit sliderPressed();
    } else if ( e->button() == MidButton ) {
        int pos = goodPart( e->pos() );
        moveSlider( pos - slideLength / 2 );
        state = Dragging;
        clickOffset = slideLength / 2;
    } else if ( orient == Horizontal && e->pos().x() < r.left() //### goodPart
                || orient == Vertical && e->pos().y() < r.top() ) {
        if ( QApplication::reverseLayout() ) {
            state = TimingUp;
            addPage();
        } else {
            state = TimingDown;
            subtractPage();
        }
        if ( !timer )
            timer = new QTimer( this );
        connect( timer, SIGNAL(timeout()), SLOT(repeatTimeout()) );
        timer->start( thresholdTime, TRUE );
    } else if ( orient == Horizontal && e->pos().x() > r.right() //### goodPart
                || orient == Vertical && e->pos().y() > r.bottom() ) {
        if ( QApplication::reverseLayout() ) {
            state = TimingDown;
            subtractPage();
        } else {
            state = TimingUp;
            addPage();
        }
        if ( !timer )
            timer = new QTimer( this );
        connect( timer, SIGNAL(timeout()), SLOT(repeatTimeout()) );
        timer->start( thresholdTime, TRUE );
    }
    update( sliderRect() );
}

/*!
    \reimp
*/
void QSlider::mouseMoveEvent( QMouseEvent *e )
{
    if ( state != Dragging )
        return;

    QRect r = rect();
    int m = style().pixelMetric( QStyle::PM_MaximumDragDistance,
                                 this );
    if ( m >= 0 ) {
        if ( orientation() == Horizontal )
            r.setRect( r.x() - m, r.y() - 2*m/3,
                       r.width() + 2*m, r.height() + 3*m );
        else
            r.setRect( r.x() - 2*m/3, r.y() - m,
                       r.width() + 3*m, r.height() + 2*m );
        if ( !r.contains( e->pos() ) ) {
            moveSlider( positionFromValue(d->sliderStartVal) );
            return;
        }
    }

    int pos = goodPart( e->pos() );
    moveSlider( pos - clickOffset );
}

/*!
    \reimp
*/
#ifndef QT_NO_WHEELEVENT
void QSlider::wheelEvent( QWheelEvent * e )
{
    if ( e->orientation() != orientation() && !rect().contains(e->pos()) )
        return;

    static float offset = 0;
    static QSlider* offset_owner = 0;
    if (offset_owner != this){
        offset_owner = this;
        offset = 0;
    }
    offset += -e->delta()*QMAX(pageStep(),lineStep())/120;
    if (QABS(offset)<1)
        return;
    setValue( value() + int(offset) );
    offset -= int(offset);
    e->accept();
}
#endif

/*!
    \reimp
*/
void QSlider::mouseReleaseEvent( QMouseEvent * )
{
    resetState();
    update( sliderRect() );
}

/*!
    \reimp
*/
void QSlider::focusInEvent( QFocusEvent * e)
{
    QWidget::focusInEvent( e );
}

/*!
    \reimp
*/
void QSlider::focusOutEvent( QFocusEvent * e )
{
    QWidget::focusOutEvent( e );
}

/*!
    Moves the left (or top) edge of the slider to position \a pos. The
    slider is actually moved to the step position nearest the given \a
    pos.
*/

void QSlider::moveSlider( int pos )
{
    int  a = available();
    int newPos = QMIN( a, QMAX( 0, pos ) );
    int newVal = valueFromPosition( newPos );
    if (style().styleHint(QStyle::SH_Slider_SnapToValue, this))
        newPos = positionFromValue( newVal );
    if ( sliderPos != newPos )
        reallyMoveSlider( newPos );
    if ( sliderVal != newVal ) {
        sliderVal = newVal;
        emit sliderMoved( sliderVal );
    }
    if ( tracking() && sliderVal != value() )
        setValue( sliderVal );

}


/*
    Resets all state information and stops the timer.
*/

void QSlider::resetState()
{
    if ( timer ) {
        timer->stop();
        timer->disconnect();
    }
    switch ( state ) {
    case TimingUp:
    case TimingDown:
        break;
    case Dragging: {
        setValue( valueFromPosition( sliderPos ) );
        emit sliderReleased();
        break;
    }
    case Idle:
        break;
    default:
        qWarning("QSlider: (%s) in wrong state", name( "unnamed" ) );
    }
    state = Idle;
}


/*!
    \reimp
*/
void QSlider::keyPressEvent( QKeyEvent *e )
{
    bool sloppy = bool(style().styleHint(QStyle::SH_Slider_SloppyKeyEvents, this));
    switch ( e->key() ) {
    case Key_Left:
        if ( sloppy || orient == Horizontal ) {
            if (QApplication::reverseLayout())
                addLine();
            else
                subtractLine();
        }
        break;
    case Key_Right:
        if ( sloppy || orient == Horizontal ) {
            if (QApplication::reverseLayout())
                subtractLine();
            else
                addLine();
        }
        break;
    case Key_Up:
        if ( sloppy || orient == Vertical )
            subtractLine();
        break;
    case Key_Down:
        if ( sloppy || orient == Vertical )
            addLine();
        break;
    case Key_Prior:
        subtractPage();
        break;
    case Key_Next:
        addPage();
        break;
    case Key_Home:
        setValue( minValue() );
        break;
    case Key_End:
        setValue( maxValue() );
        break;
    default:
        e->ignore();
        return;
    }
}

void QSlider::setValue( int value )
{
    QRangeControl::setValue( value );
#if defined(QT_ACCESSIBILITY_SUPPORT)
    QAccessible::updateAccessibility( this, 0, QAccessible::ValueChanged );
#endif
}


/*! \reimp
*/

void QSlider::addLine()
{
    QRangeControl::addLine();
}

/*! \reimp
*/

void QSlider::subtractLine()
{
    QRangeControl::subtractLine();
}

/*!
    Moves the slider one pageStep() up or right.
*/

void QSlider::addStep()
{
    addPage();
}


/*!
    Moves the slider one pageStep() down or left.
*/

void QSlider::subtractStep()
{
    subtractPage();
}


/*
  Waits for autorepeat.
*/

void QSlider::repeatTimeout()
{
    Q_ASSERT( timer );
    timer->disconnect();
    if ( state == TimingDown )
        connect( timer, SIGNAL(timeout()), SLOT(subtractStep()) );
    else if ( state == TimingUp )
        connect( timer, SIGNAL(timeout()), SLOT(addStep()) );
    timer->start( repeatTime, FALSE );
}


/*
  Returns the relevant dimension of \a p.
*/

int QSlider::goodPart( const QPoint &p ) const
{
    return (orient == Horizontal) ?  p.x() : p.y();
}

/*!
    \reimp
*/
QSize QSlider::sizeHint() const
{
    constPolish();
    const int length = 84, tickSpace = 5;
    int thick = style().pixelMetric( QStyle::PM_SliderThickness, this );
    if ( ticks & Above )
        thick += tickSpace;
    if ( ticks & Below )
        thick += tickSpace;
    int w = thick, h = length;
    if ( orient == Horizontal ) {
        w = length;
        h = thick;
    }
    return (style().sizeFromContents(QStyle::CT_Slider, this,
                                     QSize(w, h)).expandedTo(QApplication::globalStrut()));
}



/*!
    \reimp
*/

QSize QSlider::minimumSizeHint() const
{
    QSize s = sizeHint();
    int length = style().pixelMetric(QStyle::PM_SliderLength, this);
    if ( orient == Horizontal )
        s.setWidth( length );
    else
        s.setHeight( length );

    return s;
}

/*! \fn void QSlider::setSizePolicy( QSizePolicy::SizeType, QSizePolicy::SizeType, bool )
    \reimp
*/

/*! \reimp */
void QSlider::setSizePolicy( QSizePolicy sp )
{
    // ## remove 4.0
    QWidget::setSizePolicy( sp );
}

/*! \reimp */
QSizePolicy QSlider::sizePolicy() const
{
    // ### 4.0 remove this reimplementation
    return QWidget::sizePolicy();
}

/*!
    \property QSlider::tickmarks
    \brief the tickmark settings for this slider

    The valid values are in \l{QSlider::TickSetting}. The default is
    \c NoMarks.

    \sa tickInterval
*/

void QSlider::setTickmarks( TickSetting s )
{
    ticks = s;
    initTicks();
    update();
}


/*!
    \property QSlider::tickInterval
    \brief the interval between tickmarks

    This is a value interval, not a pixel interval. If it is 0, the
    slider will choose between lineStep() and pageStep(). The initial
    value of tickInterval is 0.

    \sa QRangeControl::lineStep(), QRangeControl::pageStep()
*/

void QSlider::setTickInterval( int i )
{
    tickInt = QMAX( 0, i );
    update();
}


/*!
    \reimp
*/
void QSlider::styleChange( QStyle& old )
{
    QWidget::styleChange( old );
}

/*!
    \property QSlider::minValue
    \brief the current minimum value of the slider

    When setting this property, the \l QSlider::maxValue is adjusted,
    if necessary, to ensure that the range remains valid.

    \sa setRange()
*/
int QSlider::minValue() const
{
    return QRangeControl::minValue();
}

/*!
    \property QSlider::maxValue
    \brief the current maximum value of the slider

    When setting this property, the \l QSlider::minValue is adjusted,
    if necessary, to ensure that the range remains valid.

    \sa setRange()
*/
int QSlider::maxValue() const
{
    return QRangeControl::maxValue();
}

void QSlider::setMinValue( int minVal )
{
    QRangeControl::setMinValue( minVal );
}

void QSlider::setMaxValue( int maxVal )
{
    QRangeControl::setMaxValue( maxVal );
}

/*!
    \property QSlider::lineStep
    \brief the current line step

    When setting lineStep, the virtual stepChange() function will be
    called if the new line step is different from the previous
    setting.

    \sa setSteps() QRangeControl::pageStep() setRange()
*/
int QSlider::lineStep() const
{
    return QRangeControl::lineStep();
}

/*!
    \property QSlider::pageStep
    \brief the current page step

    When setting pageStep, the virtual stepChange() function will be
    called if the new page step is different from the previous
    setting.

    \sa QRangeControl::setSteps() setLineStep() setRange()
*/

int QSlider::pageStep() const
{
    return QRangeControl::pageStep();
}

void QSlider::setLineStep( int i )
{
    setSteps( i, pageStep() );
}

void QSlider::setPageStep( int i )
{
    setSteps( lineStep(), i );
}

/*!
    \property QSlider::value
    \brief the current slider value

    \sa QRangeControl::value() prevValue()
*/

int QSlider::value() const
{
    return QRangeControl::value();
}

#endif