//! Determine the value corresponding to a specified point
double QwtWheel::getValue( const QPoint &p )
{
const QRectF rect = wheelRect();
// The reference position is arbitrary, but the
// sign of the offset is important
double w, dx;
if ( orientation() == Qt::Vertical )
{
w = rect.height();
dx = rect.y() - p.y();
}
else
{
w = rect.width();
dx = p.x() - rect.x();
}
if ( w == 0.0 )
return 0.0;
// w pixels is an arc of viewAngle degrees,
// so we convert change in pixels to change in angle
const double ang = dx * d_data->viewAngle / w;
// value range maps to totalAngle degrees,
// so convert the change in angle to a change in value
const double val = ang * ( maxValue() - minValue() ) / d_data->totalAngle;
// Note, range clamping and rasterizing to step is automatically
// handled by QwtAbstractSlider, so we simply return the change in value
return val;
}
/*!
Determine the value corresponding to a specified point
\param pos Position
\return Value corresponding to pos
*/
double QwtWheel::valueAt( const QPoint &pos ) const
{
const QRectF rect = wheelRect();
double w, dx;
if ( d_data->orientation == Qt::Vertical )
{
w = rect.height();
dx = rect.top() - pos.y();
}
else
{
w = rect.width();
dx = pos.x() - rect.left();
}
if ( w == 0.0 )
return 0.0;
if ( d_data->inverted )
{
dx = w - dx;
}
// w pixels is an arc of viewAngle degrees,
// so we convert change in pixels to change in angle
const double ang = dx * d_data->viewAngle / w;
// value range maps to totalAngle degrees,
// so convert the change in angle to a change in value
const double val = ang * ( maximum() - minimum() ) / d_data->totalAngle;
return val;
}
/*!
\brief Qt Paint Event
\param event Paint event
*/
void QwtWheel::paintEvent( QPaintEvent *event )
{
QPainter painter( this );
painter.setClipRegion( event->region() );
QStyleOption opt;
opt.init(this);
style()->drawPrimitive(QStyle::PE_Widget, &opt, &painter, this);
qDrawShadePanel( &painter,
contentsRect(), palette(), true, d_data->borderWidth );
drawWheelBackground( &painter, wheelRect() );
drawTicks( &painter, wheelRect() );
if ( hasFocus() )
QwtPainter::drawFocusRect( &painter, this );
}
/*!
\brief Determine the scrolling mode and direction corresponding
to a specified point
\param p point
\param scrollMode scrolling mode
\param direction direction
*/
void QwtWheel::getScrollMode( const QPoint &p,
QwtAbstractSlider::ScrollMode &scrollMode, int &direction ) const
{
if ( wheelRect().contains( p ) )
scrollMode = QwtAbstractSlider::ScrMouse;
else
scrollMode = QwtAbstractSlider::ScrNone;
direction = 0;
}
/*!
\brief Handle wheel events
In/Decrement the value
\param event Wheel event
*/
void QwtWheel::wheelEvent( QWheelEvent *event )
{
if ( !wheelRect().contains( event->pos() ) )
{
event->ignore();
return;
}
if ( d_data->isScrolling )
return;
stopFlying();
double increment = 0.0;
if ( ( event->modifiers() & Qt::ControlModifier) ||
( event->modifiers() & Qt::ShiftModifier ) )
{
// one page regardless of delta
increment = d_data->singleStep * d_data->pageStepCount;
if ( event->delta() < 0 )
increment = -increment;
}
else
{
const int numSteps = event->delta() / 120;
increment = d_data->singleStep * numSteps;
}
if ( d_data->orientation == Qt::Vertical && d_data->inverted )
increment = -increment;
double value = boundedValue( d_data->value + increment );
if ( d_data->stepAlignment )
value = alignedValue( value );
if ( value != d_data->value )
{
d_data->value = value;
update();
Q_EMIT valueChanged( d_data->value );
Q_EMIT wheelMoved( d_data->value );
}
}
/*!
\brief Mouse press event handler
Start movement of the wheel.
\param event Mouse event
*/
void QwtWheel::mousePressEvent( QMouseEvent *event )
{
stopFlying();
d_data->isScrolling = wheelRect().contains( event->pos() );
if ( d_data->isScrolling )
{
d_data->time.start();
d_data->speed = 0.0;
d_data->mouseValue = valueAt( event->pos() );
d_data->mouseOffset = d_data->mouseValue - d_data->value;
d_data->pendingValueChanged = false;
Q_EMIT wheelPressed();
}
}
