qscrollbar.cpp

qtopia-phone-2.2.0下公共的控件实现源代码。

	return;
    setValue( value() + int(offset) );
    offset -= int(offset);
}


/*!\reimp
*/
void QScrollBar::keyPressEvent( QKeyEvent *e )
{
    //   <ul>
    //     <li>Left/Right move a horizontal scrollbar by one line.
    //     <li>Up/Down move a vertical scrollbar by one line.
    //     <li>PageUp moves up one page.
    //     <li>PageDown moves down one page.
    //     <li>Home moves to the start (minValue()).
    //     <li>End moves to the end (maxValue()).
    //   </ul>

    //   Note that unless you call setFocusPolicy(), the default NoFocus
    //   will apply and the user will not be able to use the keyboard to
    //   interact with the scrollbar.
    switch ( e->key() ) {
    case Key_Left:
	if ( orient == Horizontal )
	    subtractLine();
	break;
    case Key_Right:
	if ( orient == Horizontal )
	    addLine();
	break;
    case Key_Up:
	if ( orient == Vertical )
	    subtractLine();
	break;
    case Key_Down:
	if ( orient == Vertical )
	    addLine();
	break;
    case Key_PageUp:
	subtractPage();
	break;
    case Key_PageDown:
	addPage();
	break;
    case Key_Home:
	setValue( minValue() );
	break;
    case Key_End:
	setValue( maxValue() );
	break;
    default:
	e->ignore();
	break;
    }
}


/*!\reimp
*/
void QScrollBar::resizeEvent( QResizeEvent * )
{
    positionSliderFromValue();
}


/*!\reimp
*/
void QScrollBar::paintEvent( QPaintEvent * )
{
    QPainter p( this );
    drawControls( QStyle::AddLine | QStyle::SubLine | QStyle::AddPage |
		  QStyle::SubPage | QStyle::Slider | QStyle::First | QStyle::Last,
		  pressedControl, &p );
}

static QCOORD sliderStartPos = 0;

/*!\reimp
*/
void QScrollBar::mousePressEvent( QMouseEvent *e )
{
    if ( !(e->button() == LeftButton ||
	   (/*style() == MotifStyle &&*/ e->button() == MidButton) ) )
	return;

    if ( maxValue() == minValue() ) // nothing to be done
	return;

    clickedAt	   = TRUE;
    pressedControl = pointOver( e->pos() );

    if ( (pressedControl == QStyle::AddPage ||
	  pressedControl == QStyle::SubPage ||
	  pressedControl == QStyle::Slider ) &&
	 /*style() == MotifStyle &&*/
	 e->button() == MidButton ) {
	int sliderMin, dummy2, dummy3, sliderLength;
	metrics( sliderMin, dummy2, sliderLength, dummy3 );
	int newSliderPos = (HORIZONTAL ? e->pos().x() : e->pos().y())
			   - sliderLength/2;
	newSliderPos = QMAX( sliderMin, newSliderPos );
	setValue( sliderPosToRangeValue(newSliderPos) );
	sliderPos = newSliderPos;
	pressedControl = QStyle::Slider;
    }

    if ( pressedControl == QStyle::Slider ) {
	clickOffset = (QCOORD)( (HORIZONTAL ? e->pos().x() : e->pos().y())
				- sliderPos );
	slidePrevVal   = value();
	sliderStartPos = sliderPos;
	drawControls( pressedControl, pressedControl );
	emit sliderPressed();
    } else if ( pressedControl != QStyle::NoScroll ) {
	drawControls( pressedControl, pressedControl );
	action( (QStyle::ScrollControl) pressedControl );
	startAutoRepeat();
    }
}


/*!\reimp
*/
void QScrollBar::mouseReleaseEvent( QMouseEvent *e )
{
    if ( !clickedAt || !( e->button() == LeftButton ||
			  e->button() == MidButton ) )
	return;
    QStyle::ScrollControl tmp = (QStyle::ScrollControl) pressedControl;
    clickedAt = FALSE;
    stopAutoRepeat();
    mouseMoveEvent( e );  // Might have moved since last mouse move event.
    pressedControl = QStyle::NoScroll;

    if (tmp == QStyle::Slider) {
	directSetValue( calculateValueFromSlider() );
	emit sliderReleased();
	if ( value() != prevValue() )
	    emit valueChanged( value() );
    }
    drawControls( tmp, pressedControl );
    if ( e->button() == MidButton )
	repaint( FALSE );
}


/*!\reimp
*/
void QScrollBar::mouseMoveEvent( QMouseEvent *e )
{
    if ( !isVisible() ) {
	clickedAt = FALSE;
	return;
    }

    if ( !clickedAt || !(e->state() & LeftButton ||
			 ((e->state() & MidButton) /*&&
			  style() == MotifStyle*/)) )
	return;
    int newSliderPos;
    if ( pressedControl == QStyle::Slider ) {
	int sliderMin, sliderMax;
	sliderMinMax( sliderMin, sliderMax );
	QRect r = rect();
	int m = style().maximumSliderDragDistance();
	if ( m >= 0 ) {
	    if ( orientation() == Horizontal )
		r.setRect( r.x() - m, r.y() - 2*m, r.width() + 2*m, r.height() + 4*m );
	    else
		r.setRect( r.x() - 2*m, r.y() - m, r.width() + 4*m, r.height() + 2*m );
	    if ( style() == WindowsStyle && !r.contains( e->pos() ) )
		newSliderPos = sliderStartPos;
	    else
		newSliderPos = (HORIZONTAL ? e->pos().x() :
				e->pos().y()) -clickOffset;
	}
	else
	    newSliderPos = (HORIZONTAL ? e->pos().x() :
			    e->pos().y()) -clickOffset;

	if ( newSliderPos < sliderMin )
	    newSliderPos = sliderMin;
	else if ( newSliderPos > sliderMax )
	    newSliderPos = sliderMax;
	if ( newSliderPos == sliderPos )
	    return;
	int newVal = sliderPosToRangeValue(newSliderPos);
	if ( newVal != slidePrevVal )
	    emit sliderMoved( newVal );
	if ( track && newVal != value() ) {
	    directSetValue( newVal ); // Set directly, painting done below
	    emit valueChanged( value() );
	}
	slidePrevVal = newVal;
	sliderPos = (QCOORD)newSliderPos;
	drawControls( QStyle::AddPage | QStyle::Slider | QStyle::SubPage,
		      pressedControl );
    }
    else if ( style() == WindowsStyle ) {
	// stop scrolling when the mouse pointer leaves a control
	// similar to push buttons
	if ( (int)pressedControl != pointOver( e->pos() ) ) {
	    drawControls( pressedControl, QStyle::NoScroll );
	    stopAutoRepeat();
	} else if ( !repeater ) {
	    drawControls( pressedControl, pressedControl );
	    action( (QStyle::ScrollControl) pressedControl );
	    startAutoRepeat();
	}
    }
}


/*!
  \fn int QScrollBar::sliderStart() const
  Returns the pixel position where the scroll bar slider starts.

  It is equivalent to sliderRect().y() for vertical
  scroll bars or sliderRect().x() for horizontal scroll bars.
*/

/*!
  Returns the scroll bar slider rectangle.
  \sa sliderStart()
*/

QRect QScrollBar::sliderRect() const
{
    int sliderMin, sliderMax, sliderLength, buttonDim;
    metrics( sliderMin, sliderMax, sliderLength, buttonDim );
    int b = style() == MotifStyle ? MOTIF_BORDER : 0;

    if ( HORIZONTAL )
	return QRect( sliderStart(), b,
		      sliderLength, height() - b*2 );
    else
	return QRect( b, sliderStart(),
		      width() - b*2, sliderLength );
}

void QScrollBar::positionSliderFromValue()
{
    sliderPos = (QCOORD)rangeValueToSliderPos( value() );
}

int QScrollBar::calculateValueFromSlider() const
{
    return sliderPosToRangeValue( sliderPos );
}


void QScrollBar::sliderMinMax( int &sliderMin, int &sliderMax) const
{
    int dummy1, dummy2;
    metrics( sliderMin, sliderMax, dummy1, dummy2 );
}


void QScrollBar::metrics( int &sliderMin, int &sliderMax,
			  int &sliderLength, int& buttonDim ) const
{

    style().scrollBarMetrics( this, sliderMin, sliderMax, sliderLength, buttonDim);
}


QStyle::ScrollControl QScrollBar::pointOver(const QPoint &p) const
{
    return style().scrollBarPointOver(this, sliderStart(), p);
}


int QScrollBar::rangeValueToSliderPos( int v ) const
{
    int sliderMin, sliderMax;
    sliderMinMax( sliderMin, sliderMax );
    return positionFromValue( v, sliderMax-sliderMin ) + sliderMin;
}

int QScrollBar::sliderPosToRangeValue( int pos ) const
{
    int sliderMin, sliderMax;
    sliderMinMax( sliderMin, sliderMax );
    return  valueFromPosition( pos - sliderMin, sliderMax - sliderMin );
}


void QScrollBar::action( QStyle::ScrollControl control )
{
    switch( control ) {
    case QStyle::AddLine:
	emit nextLine();
	addLine();
	break;
    case QStyle::SubLine:
	emit prevLine();
	subtractLine();
	break;
    case QStyle::AddPage:
	emit nextPage();
	addPage();
	break;
    case QStyle::SubPage:
	emit prevPage();
	subtractPage();
	break;
    case QStyle::First:
	emit valueChanged( minValue() );
	setValue( minValue() );
	break;
    case QStyle::Last:
	emit valueChanged( maxValue() );
	setValue( maxValue() );
	break;
    default:
#if defined(CHECK_RANGE)
	    qWarning( "QScrollBar::action: (%s) internal error", name() );
#else
	    ;
#endif
    }
}


void QScrollBar::drawControls( uint controls, uint activeControl ) const
{
    if (isVisible()) {
	QPainter p ( this );
	drawControls( controls, activeControl, &p );
    }
}


void QScrollBar::drawControls( uint controls, uint activeControl,
			       QPainter *p ) const
{

    style().drawScrollBarControls( p, this, sliderStart(), controls,
				   activeControl);
    return;

}

/*!\reimp
 */
void QScrollBar::styleChange( QStyle& old )
{
    positionSliderFromValue();
    if ( style() == MotifStyle )
	setBackgroundMode( PaletteMid );
    else
	setBackgroundMode( PaletteBackground );

    QWidget::styleChange( old );
}

/*!
  \reimp
*/
int QScrollBar::minValue() const
{
    return QRangeControl::minValue();
}

/*!
  \reimp
*/
int QScrollBar::maxValue() const
{
    return QRangeControl::maxValue();
}

/*!
  A convenience function which just calls
  setRange( i, maxValue() )

  \sa setRange()
*/
void QScrollBar::setMinValue( int i )
{
    setRange( i, maxValue() );
}

/*!
  A convenience function which just calls
  setRange( minValue(), i )

  \sa setRange()
*/
void QScrollBar::setMaxValue( int i )
{
    setRange( minValue(), i );
}

/*!
  \reimp
*/
int QScrollBar::lineStep() const
{
    return QRangeControl::lineStep();
}

/*!
  \reimp
*/
int QScrollBar::pageStep() const
{
    return QRangeControl::pageStep();
}

/*!
  Sets the line step to \e i.

  Calls the virtual stepChange() function if the new line step is
  different from the previous setting.

  \sa lineStep() QRangeControl::setSteps() setPageStep() setRange()
*/
void QScrollBar::setLineStep( int i )
{
    setSteps( i, pageStep() );
}

/*!
  Sets the page step to \e i.

  Calls the virtual stepChange() function if the new page step is
  different from the previous setting.

  \sa pageStep() QRangeControl::setSteps() setLineStep() setRange()
*/
void QScrollBar::setPageStep( int i )
{
    setSteps( lineStep(), i );
}

/*!
  \reimp
*/
int QScrollBar::value() const
{
    return QRangeControl::value();
}

/*!
  \reimp
*/
void QScrollBar::setValue( int i )
{
    QRangeControl::setValue( i );
}

#undef ADD_LINE_ACTIVE
#undef SUB_LINE_ACTIVE
#endif