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QwtSlider(3) Qwt User's Guide QwtSlider(3)

NAME

QwtSlider -
The Slider Widget.
 

SYNOPSIS

#include <qwt_slider.h>
Inherits QwtAbstractSlider, and QwtAbstractScale.

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 QwtScaleDraw * scaleDraw () const
 
const QwtScaleEngine * scaleEngine () const
 
QwtScaleEngine * scaleEngine ()
 
const QwtScaleMap & scaleMap () 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 QwtAbstractScaleDraw * abstractScaleDraw () const
 
QwtAbstractScaleDraw * abstractScaleDraw ()
 
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 ()
 
QwtScaleDraw * scaleDraw ()
 
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.
See also:
QwtAbstractSlider and QwtAbstractScale for the descriptions of the inherited members.
 

Member Enumeration Documentation

enum QwtSlider::BGSTYLE Background style.

See also:
QwtSlider()
 

enum QwtSlider::ScalePos 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()
 

enum QwtAbstractSlider::ScrollMode [inherited] Scroll mode

See also:
getScrollMode()
 

Constructor & Destructor Documentation

QwtSlider::QwtSlider (QWidget *parent, Qt::Orientationorientation = Qt::Horizontal, ScalePosscalePos = NoScale, BGSTYLEbgStyle = BgTrough) [explicit]

Constructor. Parameters:
parent parent widget
 
orientation Orientation of the slider. Can be Qt::Horizontal or Qt::Vertical. Defaults to Qt::Horizontal.
 
scalePos Position of the scale. Defaults to QwtSlider::NoScale.
 
bgStyle Background 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:
painter Painter
 
r Rectangle
 

void QwtSlider::drawThumb (QPainter *painter, const QRect &sliderRect, intpos) [protected, virtual] Draw the thumb at a position

Parameters:
painter Painter
 
sliderRect Bounding rectangle of the slider
 
pos Position 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 (doublevalue) [virtual, slot, inherited]

Set the slider's value to the nearest integer multiple of the step size. Parameters:
value Value
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:
p point
 
scrollMode Scrolling mode
 
direction Direction
 
Implements QwtAbstractSlider.

double QwtSlider::getValue (const QPoint &pos) [protected, virtual] Determine the value corresponding to a specified mouse location.

Parameters:
pos Mouse position
 
Implements QwtAbstractSlider.

void QwtDoubleRange::incPages (intnPages) [virtual, inherited]

Increment the value by a specified number of pages. Parameters:
nPages Number of pages to increment. A negative number decrements the value.
Warning:
The Page size is specified in the constructor.
 

void QwtAbstractSlider::incValue (intsteps) [virtual, slot, inherited]

Increment the value by a specified number of steps. Parameters:
steps number 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:
e Key event
See also:
isReadOnly()
 
Reimplemented in QwtCompass, and QwtDial.

void QwtSlider::layoutSlider (boolupdate_geometry = true) [protected] Recalculate the slider's geometry and layout based on the current rect and fonts.

Parameters:
update_geometry notify 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:
e Mouse event
 

void QwtAbstractSlider::mousePressEvent (QMouseEvent *e) [protected, virtual, inherited] Mouse press event handler

Parameters:
e Mouse event
 

void QwtAbstractSlider::mouseReleaseEvent (QMouseEvent *e) [protected, virtual, inherited] Mouse Release Event handler

Parameters:
e Mouse 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:
event Paint 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 (doublevmin, doublevmax, doublestepSize = 0.0) [protected, inherited] Recalculate the scale division and update the scale draw.

Parameters:
vmin Lower limit of the scale interval
 
vmax Upper limit of the scale interval
 
stepSize Major 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] Returns:

abstractScaleDraw()->scaleMap()
 

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 (BGSTYLEst) Set the background style.

void QwtSlider::setBorderWidth (intbd)

Change the slider's border width. Parameters:
bd border width
 

void QwtSlider::setMargins (intxMargin, intyMargin)

Set distances between the widget's border and internals. Parameters:
xMargin Horizontal margin
 
yMargin Vertical margin
 

void QwtAbstractSlider::setMass (doubleval) [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:
val New mass in kg
See also:
mass()
 
Reimplemented in QwtWheel.

void QwtSlider::setOrientation (Qt::Orientationo) [virtual]

Set the orientation. Parameters:
o Orientation. 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 (booltf) [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 .fi

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:

tf true 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 (doublevmin, doublevmax, doublevstep = 0.0, intpageSize = 1) [inherited]

Specify range and step size. Parameters:
vmin lower boundary of the interval
 
vmax higher boundary of the interval
 
vstep step width
 
pageSize page 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 (boolreadOnly) [virtual, slot, inherited] En/Disable read only mode

In read only mode the slider can't be controlled by mouse or keyboard.
Parameters:
readOnly Enables in case of true
See also:
isReadOnly()
 

void QwtAbstractScale::setScale (const QwtDoubleInterval &interval, doublestepSize = 0.0) [inherited]

Specify a scale. Disable autoscaling and define a scale by an interval and a step size
Parameters:
interval Interval
 
stepSize major step size
See also:
setAutoScale()
 

void QwtAbstractScale::setScale (doublevmin, doublevmax, doublestepSize = 0.0) [inherited]

Specify a scale. Disable autoscaling and define a scale by an interval and a step size
Parameters:
vmin lower limit of the scale interval
 
vmax upper limit of the scale interval
 
stepSize major 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:
scaleDiv Scale 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:
scaleDraw ScaleDraw 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 (intticks) [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:
ticks maximal number of major ticks.
See also:
QwtAbstractScaleDraw
 

void QwtAbstractScale::setScaleMaxMinor (intticks) [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 (ScalePoss)

Change the scale position (and slider orientation). Parameters:
s Position 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 (doublevstep) [inherited]

Change the step raster. Parameters:
vstep new step width
Warning:
The value will not be adjusted to the new step raster.
 
Reimplemented in QwtCounter.

void QwtSlider::setThumbLength (intthumbLength)

Set the slider's thumb length. Parameters:
thumbLength new length
 

void QwtSlider::setThumbWidth (intw)

Change the width of the thumb. Parameters:
w new width
 

void QwtAbstractSlider::setTracking (boolenable) [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:
enable true (enable) or false (disable) tracking.
 

void QwtAbstractSlider::setUpdateTime (intt) [inherited]

Specify the update interval for automatic scrolling. Parameters:
t update interval in milliseconds
See also:
getScrollMode()
 

void QwtAbstractSlider::setValid (boolvalid) [inline, inherited] Parameters:

valid true/false
See also:
QwtDblRange::isValid()
 
Reimplemented from QwtDoubleRange.

void QwtAbstractSlider::setValue (doubleval) [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:
val new value
See also:
fitValue()
 
Reimplemented from QwtDoubleRange.

QSize QwtSlider::sizeHint () const [virtual] Returns:

QwtSlider::minimumSizeHint()
 

void QwtAbstractSlider::sliderMoved (doublevalue) [signal, inherited] This signal is emitted when the user moves the slider with the mouse.

Parameters:
value new 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:
e Timer 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 (doublevalue) [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:
value new value
 

void QwtAbstractSlider::wheelEvent (QWheelEvent *e) [protected, virtual, inherited] Wheel Event handler

Parameters:
e Whell event
 

int QwtSlider::xyPosition (doublevalue) const [protected] Find the x/y position for a given value v

Parameters:
value Value
 
 

Author

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