Qwt User's Guide 5.2.2
Public Types | Public Slots | Signals | Public Member Functions | Protected Member Functions

QwtSlider Class Reference

The Slider Widget. More...

#include <qwt_slider.h>

Inheritance diagram for QwtSlider:
Inheritance graph
[legend]

List of all members.

Public Types

enum  BGSTYLE {
  BgTrough = 0x1,
  BgSlot = 0x2,
  BgBoth = BgTrough | BgSlot
}
enum  ScalePos {
  NoScale,
  LeftScale,
  RightScale,
  TopScale,
  BottomScale
}
enum  ScrollMode {
  ScrNone,
  ScrMouse,
  ScrTimer,
  ScrDirect,
  ScrPage
}

Public Slots

virtual void fitValue (double val)
virtual void incValue (int steps)
virtual void setReadOnly (bool)
virtual void setValue (double val)

Signals

void sliderMoved (double value)
void sliderPressed ()
void sliderReleased ()
void valueChanged (double value)

Public Member Functions

bool autoScale () const
BGSTYLE bgStyle () const
int borderWidth () const
virtual void incPages (int)
bool isReadOnly () const
bool isValid () const
virtual double mass () const
double maxValue () const
virtual QSize minimumSizeHint () const
double minValue () const
Qt::Orientation orientation () const
int pageSize () const
bool periodic () const
 QwtSlider (QWidget *parent, Qt::Orientation=Qt::Horizontal, ScalePos=NoScale, BGSTYLE bgStyle=BgTrough)
const QwtScaleDrawscaleDraw () const
const QwtScaleEnginescaleEngine () const
QwtScaleEnginescaleEngine ()
const QwtScaleMapscaleMap () const
int scaleMaxMajor () const
int scaleMaxMinor () const
ScalePos scalePosition () const
void setAutoScale ()
void setBgStyle (BGSTYLE)
void setBorderWidth (int bw)
void setMargins (int x, int y)
virtual void setMass (double val)
virtual void setOrientation (Qt::Orientation)
void setPeriodic (bool tf)
void setRange (double vmin, double vmax, double vstep=0.0, int pagesize=1)
void setScale (double vmin, double vmax, double step=0.0)
void setScale (const QwtScaleDiv &s)
void setScale (const QwtDoubleInterval &, double step=0.0)
void setScaleDraw (QwtScaleDraw *)
void setScaleEngine (QwtScaleEngine *)
void setScaleMaxMajor (int ticks)
void setScaleMaxMinor (int ticks)
void setScalePosition (ScalePos s)
void setStep (double)
void setThumbLength (int l)
void setThumbWidth (int w)
void setTracking (bool enable)
void setUpdateTime (int t)
void setValid (bool valid)
virtual QSize sizeHint () const
double step () const
void stopMoving ()
int thumbLength () const
int thumbWidth () const
double value () const

Protected Member Functions

const QwtAbstractScaleDrawabstractScaleDraw () const
QwtAbstractScaleDrawabstractScaleDraw ()
void draw (QPainter *p, const QRect &update_rect)
virtual void drawSlider (QPainter *p, const QRect &r)
virtual void drawThumb (QPainter *p, const QRect &, int pos)
double exactPrevValue () const
double exactValue () const
virtual void fontChange (const QFont &oldFont)
virtual void getScrollMode (const QPoint &p, int &scrollMode, int &direction)
virtual double getValue (const QPoint &p)
virtual void keyPressEvent (QKeyEvent *e)
void layoutSlider (bool update=true)
virtual void mouseMoveEvent (QMouseEvent *e)
double mouseOffset () const
virtual void mousePressEvent (QMouseEvent *e)
virtual void mouseReleaseEvent (QMouseEvent *e)
virtual void paintEvent (QPaintEvent *e)
double prevValue () const
virtual void rangeChange ()
void rescale (double vmin, double vmax, double step=0.0)
virtual void resizeEvent (QResizeEvent *e)
virtual void scaleChange ()
QwtScaleDrawscaleDraw ()
int scrollMode () const
void setAbstractScaleDraw (QwtAbstractScaleDraw *)
void setMouseOffset (double)
virtual void setPosition (const QPoint &)
virtual void stepChange ()
virtual void timerEvent (QTimerEvent *e)
virtual void valueChange ()
virtual void wheelEvent (QWheelEvent *e)
int xyPosition (double v) const

Detailed Description

The Slider Widget.

QwtSlider is a slider widget which operates on an interval of type double. QwtSlider supports different layouts as well as a scale.

sliders.png
See also:
QwtAbstractSlider and QwtAbstractScale for the descriptions of the inherited members.

Member Enumeration Documentation

Background style.

See also:
QwtSlider()

Scale position. QwtSlider tries to enforce valid combinations of its orientation and scale position:

  • Qt::Horizonal combines with NoScale, TopScale and BottomScale
  • Qt::Vertical combines with NoScale, LeftScale and RightScale
See also:
QwtSlider()

Scroll mode

See also:
getScrollMode()

Constructor & Destructor Documentation

QwtSlider::QwtSlider ( QWidget *  parent,
Qt::Orientation  orientation = Qt::Horizontal,
ScalePos  scalePos = NoScale,
BGSTYLE  bgStyle = BgTrough 
) [explicit]

Constructor.

Parameters:
parentparent widget
orientationOrientation of the slider. Can be Qt::Horizontal or Qt::Vertical. Defaults to Qt::Horizontal.
scalePosPosition of the scale. Defaults to QwtSlider::NoScale.
bgStyleBackground style. QwtSlider::BgTrough draws the slider button in a trough, QwtSlider::BgSlot draws a slot underneath the button. An or-combination of both may also be used. The default is QwtSlider::BgTrough.

QwtSlider enforces valid combinations of its orientation and scale position. If the combination is invalid, the scale position will be set to NoScale. Valid combinations are:

  • Qt::Horizonal with NoScale, TopScale, or BottomScale;
  • Qt::Vertical with NoScale, LeftScale, or RightScale.

Member Function Documentation

const QwtAbstractScaleDraw * QwtAbstractScale::abstractScaleDraw ( ) const [protected, inherited]
Returns:
Scale draw
See also:
setAbstractScaleDraw()
QwtAbstractScaleDraw * QwtAbstractScale::abstractScaleDraw ( ) [protected, inherited]
Returns:
Scale draw
See also:
setAbstractScaleDraw()
bool QwtAbstractScale::autoScale ( ) const [inherited]
Returns:
true if autoscaling is enabled
QwtSlider::BGSTYLE QwtSlider::bgStyle ( ) const
Returns:
the background style.
int QwtSlider::borderWidth ( ) const
Returns:
the border width.
void QwtSlider::draw ( QPainter *  p,
const QRect &  update_rect 
) [protected]

Draw the QwtSlider.

void QwtSlider::drawSlider ( QPainter *  painter,
const QRect &  r 
) [protected, virtual]

Draw the slider into the specified rectangle.

Parameters:
painterPainter
rRectangle
void QwtSlider::drawThumb ( QPainter *  painter,
const QRect &  sliderRect,
int  pos 
) [protected, virtual]

Draw the thumb at a position

Parameters:
painterPainter
sliderRectBounding rectangle of the slider
posPosition of the slider thumb
double QwtDoubleRange::exactPrevValue ( ) const [protected, inherited]

Returns the exact previous value.

double QwtDoubleRange::exactValue ( ) const [protected, inherited]

Returns the exact value.

The exact value is the value which QwtDoubleRange::value would return if the value were not adjusted to the step raster. It differs from the current value only if QwtDoubleRange::fitValue or QwtDoubleRange::incValue have been used before. This function is intended for internal use in derived classes.

void QwtAbstractSlider::fitValue ( double  value) [virtual, slot, inherited]

Set the slider's value to the nearest integer multiple of the step size.

Parameters:
valueValue
See also:
setValue(), incValue()

Reimplemented from QwtDoubleRange.

void QwtSlider::fontChange ( const QFont &  oldFont) [protected, virtual]

Notify change in font.

void QwtSlider::getScrollMode ( const QPoint &  p,
int &  scrollMode,
int &  direction 
) [protected, virtual]

Determine scrolling mode and direction.

Parameters:
ppoint
scrollModeScrolling mode
directionDirection

Implements QwtAbstractSlider.

double QwtSlider::getValue ( const QPoint &  pos) [protected, virtual]

Determine the value corresponding to a specified mouse location.

Parameters:
posMouse position

Implements QwtAbstractSlider.

void QwtDoubleRange::incPages ( int  nPages) [virtual, inherited]

Increment the value by a specified number of pages.

Parameters:
nPagesNumber of pages to increment. A negative number decrements the value.
Warning:
The Page size is specified in the constructor.
void QwtAbstractSlider::incValue ( int  steps) [virtual, slot, inherited]

Increment the value by a specified number of steps.

Parameters:
stepsnumber of steps
See also:
setValue()

Reimplemented from QwtDoubleRange.

bool QwtAbstractSlider::isReadOnly ( ) const [inherited]

In read only mode the slider can't be controlled by mouse or keyboard.

Returns:
true if read only
See also:
setReadOnly()
bool QwtAbstractSlider::isValid ( ) const [inline, inherited]
See also:
QwtDblRange::isValid()

Reimplemented from QwtDoubleRange.

void QwtAbstractSlider::keyPressEvent ( QKeyEvent *  e) [protected, virtual, inherited]

Handles key events

  • Key_Down, KeyLeft
    Decrement by 1
  • Key_Up, Key_Right
    Increment by 1
Parameters:
eKey event
See also:
isReadOnly()

Reimplemented in QwtCompass, and QwtDial.

void QwtSlider::layoutSlider ( bool  update_geometry = true) [protected]

Recalculate the slider's geometry and layout based on the current rect and fonts.

Parameters:
update_geometrynotify the layout system and call update to redraw the scale
double QwtAbstractSlider::mass ( ) const [virtual, inherited]
Returns:
mass
See also:
setMass()

Reimplemented in QwtWheel.

double QwtDoubleRange::maxValue ( ) const [inherited]

Returns the value of the second border of the range.

maxValue returns the value which has been specified as the second parameter in QwtDoubleRange::setRange.

See also:
setRange()
QSize QwtSlider::minimumSizeHint ( ) const [virtual]

Return a minimum size hint.

Warning:
The return value of QwtSlider::minimumSizeHint() depends on the font and the scale.
double QwtDoubleRange::minValue ( ) const [inherited]

Returns the value at the first border of the range.

minValue returns the value which has been specified as the first parameter in setRange().

See also:
setRange()
void QwtAbstractSlider::mouseMoveEvent ( QMouseEvent *  e) [protected, virtual, inherited]

Mouse Move Event handler

Parameters:
eMouse event
void QwtAbstractSlider::mousePressEvent ( QMouseEvent *  e) [protected, virtual, inherited]

Mouse press event handler

Parameters:
eMouse event
void QwtAbstractSlider::mouseReleaseEvent ( QMouseEvent *  e) [protected, virtual, inherited]

Mouse Release Event handler

Parameters:
eMouse event
Qt::Orientation QwtAbstractSlider::orientation ( ) const [inherited]
Returns:
Orientation
See also:
setOrientation()
int QwtDoubleRange::pageSize ( ) const [inherited]

Returns the page size in steps.

void QwtSlider::paintEvent ( QPaintEvent *  event) [protected, virtual]

Qt paint event

Parameters:
eventPaint event
bool QwtDoubleRange::periodic ( ) const [inherited]

Returns true if the range is periodic.

See also:
setPeriodic()
double QwtDoubleRange::prevValue ( ) const [protected, inherited]

Returns the previous value.

void QwtSlider::rangeChange ( ) [protected, virtual]

Notify change of range.

Reimplemented from QwtDoubleRange.

void QwtAbstractScale::rescale ( double  vmin,
double  vmax,
double  stepSize = 0.0 
) [protected, inherited]

Recalculate the scale division and update the scale draw.

Parameters:
vminLower limit of the scale interval
vmaxUpper limit of the scale interval
stepSizeMajor step size
See also:
scaleChange()
void QwtSlider::resizeEvent ( QResizeEvent *  e) [protected, virtual]

Qt resize event.

void QwtSlider::scaleChange ( ) [protected, virtual]

Notify changed scale.

Reimplemented from QwtAbstractScale.

const QwtScaleDraw * QwtSlider::scaleDraw ( ) const
Returns:
the scale draw of the slider
See also:
setScaleDraw()
QwtScaleDraw * QwtSlider::scaleDraw ( ) [protected]
Returns:
the scale draw of the slider
See also:
setScaleDraw()
const QwtScaleEngine * QwtAbstractScale::scaleEngine ( ) const [inherited]
Returns:
Scale engine
See also:
setScaleEngine()
QwtScaleEngine * QwtAbstractScale::scaleEngine ( ) [inherited]
Returns:
Scale engine
See also:
setScaleEngine()
const QwtScaleMap & QwtAbstractScale::scaleMap ( ) const [inherited]
int QwtAbstractScale::scaleMaxMajor ( ) const [inherited]
Returns:
Max. number of major tick intervals The default value is 5.
int QwtAbstractScale::scaleMaxMinor ( ) const [inherited]
Returns:
Max. number of minor tick intervals The default value is 3.
QwtSlider::ScalePos QwtSlider::scalePosition ( ) const

Return the scale position.

void QwtAbstractScale::setAbstractScaleDraw ( QwtAbstractScaleDraw scaleDraw) [protected, inherited]

Set a scale draw.

scaleDraw has to be created with new and will be deleted in ~QwtAbstractScale or the next call of setAbstractScaleDraw.

void QwtAbstractScale::setAutoScale ( ) [inherited]

Advise the widget to control the scale range internally.

Autoscaling is on by default.

See also:
setScale(), autoScale()
void QwtSlider::setBgStyle ( BGSTYLE  st)

Set the background style.

void QwtSlider::setBorderWidth ( int  bd)

Change the slider's border width.

Parameters:
bdborder width
void QwtSlider::setMargins ( int  xMargin,
int  yMargin 
)

Set distances between the widget's border and internals.

Parameters:
xMarginHorizontal margin
yMarginVertical margin
void QwtAbstractSlider::setMass ( double  val) [virtual, inherited]

Set the slider's mass for flywheel effect.

If the slider's mass is greater then 0, it will continue to move after the mouse button has been released. Its speed decreases with time at a rate depending on the slider's mass. A large mass means that it will continue to move for a long time.

Derived widgets may overload this function to make it public.

Parameters:
valNew mass in kg
See also:
mass()

Reimplemented in QwtWheel.

void QwtSlider::setOrientation ( Qt::Orientation  o) [virtual]

Set the orientation.

Parameters:
oOrientation. Allowed values are Qt::Horizontal and Qt::Vertical.

If the new orientation and the old scale position are an invalid combination, the scale position will be set to QwtSlider::NoScale.

See also:
QwtAbstractSlider::orientation()

Reimplemented from QwtAbstractSlider.

void QwtDoubleRange::setPeriodic ( bool  tf) [inherited]

Make the range periodic.

When the range is periodic, the value will be set to a point inside the interval such that

point = value + n * width 

if the user tries to set a new value which is outside the range. If the range is nonperiodic (the default), values outside the range will be clipped.

Parameters:
tftrue for a periodic range
void QwtAbstractSlider::setPosition ( const QPoint &  p) [protected, virtual, inherited]

Move the slider to a specified point, adjust the value and emit signals if necessary.

void QwtDoubleRange::setRange ( double  vmin,
double  vmax,
double  vstep = 0.0,
int  pageSize = 1 
) [inherited]

Specify range and step size.

Parameters:
vminlower boundary of the interval
vmaxhigher boundary of the interval
vstepstep width
pageSizepage size in steps
Warning:
  • A change of the range changes the value if it lies outside the new range. The current value will *not* be adjusted to the new step raster.
  • vmax < vmin is allowed.
  • If the step size is left out or set to zero, it will be set to 1/100 of the interval length.
  • If the step size has an absurd value, it will be corrected to a better one.
void QwtAbstractSlider::setReadOnly ( bool  readOnly) [virtual, slot, inherited]

En/Disable read only mode

In read only mode the slider can't be controlled by mouse or keyboard.

Parameters:
readOnlyEnables in case of true
See also:
isReadOnly()
void QwtAbstractScale::setScale ( const QwtDoubleInterval interval,
double  stepSize = 0.0 
) [inherited]

Specify a scale.

Disable autoscaling and define a scale by an interval and a step size

Parameters:
intervalInterval
stepSizemajor step size
See also:
setAutoScale()
void QwtAbstractScale::setScale ( double  vmin,
double  vmax,
double  stepSize = 0.0 
) [inherited]

Specify a scale.

Disable autoscaling and define a scale by an interval and a step size

Parameters:
vminlower limit of the scale interval
vmaxupper limit of the scale interval
stepSizemajor step size
See also:
setAutoScale()
void QwtAbstractScale::setScale ( const QwtScaleDiv scaleDiv) [inherited]

Specify a scale.

Disable autoscaling and define a scale by a scale division

Parameters:
scaleDivScale division
See also:
setAutoScale()
void QwtSlider::setScaleDraw ( QwtScaleDraw scaleDraw)

Set a scale draw.

For changing the labels of the scales, it is necessary to derive from QwtScaleDraw and overload QwtScaleDraw::label().

Parameters:
scaleDrawScaleDraw object, that has to be created with new and will be deleted in ~QwtSlider or the next call of setScaleDraw().
void QwtAbstractScale::setScaleEngine ( QwtScaleEngine scaleEngine) [inherited]

Set a scale engine.

The scale engine is responsible for calculating the scale division, and in case of auto scaling how to align the scale.

scaleEngine has to be created with new and will be deleted in ~QwtAbstractScale or the next call of setScaleEngine.

void QwtAbstractScale::setScaleMaxMajor ( int  ticks) [inherited]

Set the maximum number of major tick intervals.

The scale's major ticks are calculated automatically such that the number of major intervals does not exceed ticks. The default value is 5.

Parameters:
ticksmaximal number of major ticks.
See also:
QwtAbstractScaleDraw
void QwtAbstractScale::setScaleMaxMinor ( int  ticks) [inherited]

Set the maximum number of minor tick intervals.

The scale's minor ticks are calculated automatically such that the number of minor intervals does not exceed ticks. The default value is 3.

Parameters:
ticks
See also:
QwtAbstractScaleDraw
void QwtSlider::setScalePosition ( ScalePos  s)

Change the scale position (and slider orientation).

Parameters:
sPosition of the scale.

A valid combination of scale position and orientation is enforced:

  • if the new scale position is Left or Right, the scale orientation will become Qt::Vertical;
  • if the new scale position is Bottom or Top the scale orientation will become Qt::Horizontal;
  • if the new scale position is QwtSlider::NoScale, the scale orientation will not change.
void QwtDoubleRange::setStep ( double  vstep) [inherited]

Change the step raster.

Parameters:
vstepnew step width
Warning:
The value will not be adjusted to the new step raster.

Reimplemented in QwtCounter.

void QwtSlider::setThumbLength ( int  thumbLength)

Set the slider's thumb length.

Parameters:
thumbLengthnew length
void QwtSlider::setThumbWidth ( int  w)

Change the width of the thumb.

Parameters:
wnew width
void QwtAbstractSlider::setTracking ( bool  enable) [inherited]

Enables or disables tracking.

If tracking is enabled, the slider emits a valueChanged() signal whenever its value changes (the default behaviour). If tracking is disabled, the value changed() signal will only be emitted if:

  • the user releases the mouse button and the value has changed or
  • at the end of automatic scrolling.

Tracking is enabled by default.

Parameters:
enabletrue (enable) or false (disable) tracking.
void QwtAbstractSlider::setUpdateTime ( int  t) [inherited]

Specify the update interval for automatic scrolling.

Parameters:
tupdate interval in milliseconds
See also:
getScrollMode()
void QwtAbstractSlider::setValid ( bool  valid) [inline, inherited]
Parameters:
validtrue/false
See also:
QwtDblRange::isValid()

Reimplemented from QwtDoubleRange.

void QwtAbstractSlider::setValue ( double  val) [virtual, slot, inherited]

Move the slider to a specified value.

This function can be used to move the slider to a value which is not an integer multiple of the step size.

Parameters:
valnew value
See also:
fitValue()

Reimplemented from QwtDoubleRange.

QSize QwtSlider::sizeHint ( ) const [virtual]
void QwtAbstractSlider::sliderMoved ( double  value) [signal, inherited]

This signal is emitted when the user moves the slider with the mouse.

Parameters:
valuenew value
void QwtAbstractSlider::sliderPressed ( ) [signal, inherited]

This signal is emitted when the user presses the movable part of the slider (start ScrMouse Mode).

void QwtAbstractSlider::sliderReleased ( ) [signal, inherited]

This signal is emitted when the user releases the movable part of the slider.

double QwtDoubleRange::step ( ) const [inherited]
Returns:
the step size
See also:
setStep(), setRange()

Reimplemented in QwtCounter.

void QwtDoubleRange::stepChange ( ) [protected, virtual, inherited]

Notify a change of the step size.

This virtual function is called whenever the step size changes. The default implementation does nothing.

void QwtAbstractSlider::stopMoving ( ) [inherited]

Stop updating if automatic scrolling is active.

int QwtSlider::thumbLength ( ) const
Returns:
the thumb length.
int QwtSlider::thumbWidth ( ) const
Returns:
the thumb width.
void QwtAbstractSlider::timerEvent ( QTimerEvent *  e) [protected, virtual, inherited]

Qt timer event

Parameters:
eTimer event
double QwtDoubleRange::value ( ) const [inherited]

Returns the current value.

Reimplemented in QwtCounter.

void QwtSlider::valueChange ( ) [protected, virtual]

Notify change of value.

Reimplemented from QwtAbstractSlider.

void QwtAbstractSlider::valueChanged ( double  value) [signal, inherited]

Notify a change of value.

In the default setting (tracking enabled), this signal will be emitted every time the value changes ( see setTracking() ).

Parameters:
valuenew value
void QwtAbstractSlider::wheelEvent ( QWheelEvent *  e) [protected, virtual, inherited]

Wheel Event handler

Parameters:
eWhell event
int QwtSlider::xyPosition ( double  value) const [protected]

Find the x/y position for a given value v

Parameters:
valueValue