QwtKnob - Man Page

enum ScrollMode { ScrNone, ScrMouse, ScrTimer, ScrDirect, ScrPage }
enum Symbol { Line, Dot }

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

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

bool autoScale () const
int borderWidth () const
virtual void incPages (int)
bool isReadOnly () const
bool isValid () const
int knobWidth () 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
QwtKnob (QWidget *parent=NULL)
const QwtRoundScaleDraw * scaleDraw () const
QwtRoundScaleDraw * scaleDraw ()
QwtScaleEngine * scaleEngine ()
const QwtScaleEngine * scaleEngine () const
const QwtScaleMap & scaleMap () const
int scaleMaxMajor () const
int scaleMaxMinor () const
void setAutoScale ()
void setBorderWidth (int bw)
void setKnobWidth (int w)
virtual void setMass (double val)
virtual void setOrientation (Qt::Orientation o)
void setPeriodic (bool tf)
void setRange (double vmin, double vmax, double vstep=0.0, int pagesize=1)
void setScale (const QwtScaleDiv &s)
void setScale (double vmin, double vmax, double step=0.0)
void setScale (const QwtDoubleInterval &, double step=0.0)
void setScaleDraw (QwtRoundScaleDraw *)
void setScaleEngine (QwtScaleEngine *)
void setScaleMaxMajor (int ticks)
void setScaleMaxMinor (int ticks)
void setStep (double)
void setSymbol (Symbol)
void setTotalAngle (double angle)
void setTracking (bool enable)
void setUpdateTime (int t)
void setValid (bool valid)
virtual QSize sizeHint () const
double step () const
void stopMoving ()
Symbol symbol () const
double totalAngle () const
double value () const
virtual ~QwtKnob ()

const QwtAbstractScaleDraw * abstractScaleDraw () const
QwtAbstractScaleDraw * abstractScaleDraw ()
void draw (QPainter *p, const QRect &ur)
void drawKnob (QPainter *p, const QRect &r)
void drawMarker (QPainter *p, double arc, const QColor &c)
double exactPrevValue () const
double exactValue () const
virtual void keyPressEvent (QKeyEvent *e)
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
void rescale (double vmin, double vmax, double step=0.0)
virtual void resizeEvent (QResizeEvent *e)
int scrollMode () const
void setAbstractScaleDraw (QwtAbstractScaleDraw *)
void setMouseOffset (double)
virtual void setPosition (const QPoint &)
virtual void stepChange ()
virtual void timerEvent (QTimerEvent *e)
virtual void wheelEvent (QWheelEvent *e)

See also:

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Parameters:

parent Parent widget

Destructor.

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Return the border width.

Parameters:

painter Painter
rect Update rectangle

Draw the knob. Parameters:

Draw the marker at the knob's front. Parameters:

Returns the exact previous value.

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.

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

See also:

Reimplemented from QwtDoubleRange.

Increment the value by a specified number of pages. Parameters:

Warning:

The Page size is specified in the constructor.

Increment the value by a specified number of steps. Parameters:

See also:

Reimplemented from QwtDoubleRange.

Returns:

true if read only

See also:

setReadOnly()

Reimplemented from QwtDoubleRange.

• Key_Down, KeyLeft
  Decrement by 1
• Key_Up, Key_Right
  Increment by 1

Parameters:

e Key event

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isReadOnly()

Reimplemented in QwtCompass, and QwtDial.

Return the width of the knob.

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Reimplemented in QwtWheel.

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.

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Return a minimum size hint. Warning:

Returns the value at the first border of the range. minValue returns the value which has been specified as the first parameter in setRange().

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Parameters:

e Mouse event

Parameters:

e Mouse event

Parameters:

e Mouse event

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Returns the page size in steps.

Parameters:

e Paint event

Returns true if the range is periodic. See also:

Returns the previous value.

Parameters:

vmin Lower limit of the scale interval
vmax Upper limit of the scale interval
stepSize Major step size

See also:

scaleChange()

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

Advise the widget to control the scale range internally. Autoscaling is on by default.

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Set the knob's border width. Parameters:

Change the knob's width. The specified width must be >= 5, or it will be clipped.

Parameters:

w New width

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.

Set the orientation. Parameters:

Reimplemented in QwtSlider, and QwtWheel.

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

Specify range and step size. Parameters:

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.

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

Parameters:

readOnly Enables in case of true

See also:

isReadOnly()

Specify a scale. Disable autoscaling and define a scale by a scale division

Parameters:

scaleDiv Scale division

See also:

setAutoScale()

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()

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()

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

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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.

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

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

Change the step raster. Parameters:

Warning:

The value will not be adjusted to the new step raster.

Reimplemented in QwtCounter.

Set the symbol of the knob. See also:

Set the total angle by which the knob can be turned. Parameters:

The default angle is 270 degrees. It is possible to specify an angle of more than 360 degrees so that the knob can be turned several times around its axis.

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.

Specify the update interval for automatic scrolling. Parameters:

See also:

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Reimplemented from QwtDoubleRange.

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

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fitValue()

Reimplemented from QwtDoubleRange.

Parameters:

value new value

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Reimplemented in QwtCounter.

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

Stop updating if automatic scrolling is active.

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Parameters:

e Timer event

Return the total angle.

Returns the current value.

Reimplemented in QwtCounter.

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

Parameters:

e Whell event