QwtWheel - Man Page

The Wheel Widget.

Synopsis

#include <qwt_wheel.h>

Inherits QWidget.

Public Slots

void setValue (double)
Set a new value without adjusting to the step raster.
void setTotalAngle (double)
Set the total angle which the wheel can be turned.
void setViewAngle (double)
Specify the visible portion of the wheel.
void setMass (double)
Set the slider's mass for flywheel effect.

Signals

void valueChanged (double value)
Notify a change of value.
void wheelPressed ()
void wheelReleased ()
void wheelMoved (double value)

Public Member Functions

QwtWheel (QWidget *parent=NULL)
Constructor.
virtual ~QwtWheel ()
Destructor.
double value () const
void setOrientation (Qt::Orientation)
Set the wheel's orientation.
Qt::Orientation orientation () const
double totalAngle () const
double viewAngle () const
void setTickCount (int)
Adjust the number of grooves in the wheel's surface.
int tickCount () const
void setWheelWidth (int)
Set the width of the wheel.
int wheelWidth () const
void setWheelBorderWidth (int)
Set the wheel border width of the wheel.
int wheelBorderWidth () const
void setBorderWidth (int)
Set the border width.
int borderWidth () const
void setInverted (bool)
En/Disable inverted appearance.
bool isInverted () const
void setWrapping (bool)
En/Disable wrapping.
bool wrapping () const
void setSingleStep (double)
Set the step size of the counter.
double singleStep () const
void setPageStepCount (int)
Set the page step count.
int pageStepCount () const
void setStepAlignment (bool on)
En/Disable step alignment.
bool stepAlignment () const
void setRange (double min, double max)
Set the minimum and maximum values.
void setMinimum (double)
double minimum () const
void setMaximum (double)
double maximum () const
void setUpdateInterval (int)
Specify the update interval when the wheel is flying.
int updateInterval () const
void setTracking (bool)
En/Disable tracking.
bool isTracking () const
double mass () const

Protected Member Functions

virtual void paintEvent (QPaintEvent *)
Qt Paint Event.
virtual void mousePressEvent (QMouseEvent *)
Mouse press event handler.
virtual void mouseReleaseEvent (QMouseEvent *)
Mouse Release Event handler.
virtual void mouseMoveEvent (QMouseEvent *)
Mouse Move Event handler.
virtual void keyPressEvent (QKeyEvent *)
virtual void wheelEvent (QWheelEvent *)
Handle wheel events.
virtual void timerEvent (QTimerEvent *)
Qt timer event.
void stopFlying ()
Stop the flying movement of the wheel.
QRect wheelRect () const
virtual QSize sizeHint () const
virtual QSize minimumSizeHint () const
virtual void drawTicks (QPainter *, const QRectF &)
virtual void drawWheelBackground (QPainter *, const QRectF &)
virtual double valueAt (const QPoint &) const

Detailed Description

The Wheel Widget.

The wheel widget can be used to change values over a very large range in very small steps. Using the setMass() member, it can be configured as a flying wheel.

The default range of the wheel is [0.0, 100.0]

See also

The radio example.

Member Function Documentation

int QwtWheel::borderWidth () const

Returns

Border width

See also

setBorderWidth()

void QwtWheel::drawTicks (QPainter * painter, const QRectF & rect) [protected], [virtual]

Draw the Wheel's ticks

Parameters

painter Painter
rect Geometry for the wheel

void QwtWheel::drawWheelBackground (QPainter * painter, const QRectF & rect) [protected], [virtual]

Draw the Wheel's background gradient

Parameters

painter Painter
rect Geometry for the wheel

bool QwtWheel::isInverted () const

Returns

True, when the wheel is inverted

See also

setInverted()

bool QwtWheel::isTracking () const

Returns

True, when tracking is enabled

See also

setTracking(), valueChanged(), wheelMoved()

void QwtWheel::keyPressEvent (QKeyEvent * event) [protected], [virtual]

Handle key events

  • Qt::Key_Home
    Step to minimum()
  • Qt::Key_End
    Step to maximum()
  • Qt::Key_Up
    In case of a horizontal or not inverted vertical wheel the value will be incremented by the step size. For an inverted vertical wheel the value will be decremented by the step size.
  • Qt::Key_Down
    In case of a horizontal or not inverted vertical wheel the value will be decremented by the step size. For an inverted vertical wheel the value will be incremented by the step size.
  • Qt::Key_PageUp
    The value will be incremented by pageStepSize() * singleStepSize().
  • Qt::Key_PageDown
    The value will be decremented by pageStepSize() * singleStepSize().
Parameters

event Key event

double QwtWheel::mass () const

Returns

mass

See also

setMass()

double QwtWheel::maximum () const

Returns

The maximum of the range

See also

setRange(), setMaximum(), minimum()

double QwtWheel::minimum () const

Returns

The minimum of the range

See also

setRange(), setMinimum(), maximum()

QSize QwtWheel::minimumSizeHint () const [protected], [virtual]

Returns

Minimum size hint

Warning

The return value is based on the wheel width.

void QwtWheel::mouseMoveEvent (QMouseEvent * event) [protected], [virtual]

Mouse Move Event handler. Turn the wheel according to the mouse position

Parameters

event Mouse event

void QwtWheel::mousePressEvent (QMouseEvent * event) [protected], [virtual]

Mouse press event handler. Start movement of the wheel.

Parameters

event Mouse event

void QwtWheel::mouseReleaseEvent (QMouseEvent * event) [protected], [virtual]

Mouse Release Event handler. When the wheel has no mass the movement of the wheel stops, otherwise it starts flying.

Parameters

event Mouse event

Qt::Orientation QwtWheel::orientation () const

Returns

Orientation

See also

setOrientation()

int QwtWheel::pageStepCount () const

Returns

Page step count

See also

setPageStepCount(), singleStep()

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

Qt Paint Event.

Parameters

event Paint event

void QwtWheel::setBorderWidth (int width)

Set the border width. The border defaults to 2.

Parameters

width Border width

See also

borderWidth()

void QwtWheel::setInverted (bool on)

En/Disable inverted appearance. An inverted wheel increases its values in the opposite direction. The direction of an inverted horizontal wheel will be from right to left an inverted vertical wheel will increase from bottom to top.

Parameters

on En/Disable inverted appearance

See also

isInverted()

void QwtWheel::setMass (double mass) [slot]

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

mass New mass in kg

See also

mass()

void QwtWheel::setMaximum (double value)

Set the maximum value of the range

Parameters

value Maximum value

See also

setRange(), setMinimum(), maximum()

void QwtWheel::setMinimum (double value)

Set the minimum value of the range

Parameters

value Minimum value

See also

setRange(), setMaximum(), minimum()

Note

The maximum is adjusted if necessary to ensure that the range remains valid.

void QwtWheel::setOrientation (Qt::Orientation orientation)

Set the wheel's orientation. The default orientation is Qt::Horizontal.

Parameters

orientation Qt::Horizontal or Qt::Vertical.

See also

orientation()

void QwtWheel::setPageStepCount (int count)

Set the page step count. pageStepCount is a multiplicator for the single step size that typically corresponds to the user pressing PageUp or PageDown.

A value of 0 disables page stepping.

The default value is 1.

Parameters

count Multiplicator for the single step size

See also

pageStepCount(), setSingleStep()

void QwtWheel::setRange (double min, double max)

Set the minimum and maximum values. The maximum is adjusted if necessary to ensure that the range remains valid. The value might be modified to be inside of the range.

Parameters

min Minimum value
max Maximum value

See also

minimum(), maximum()

void QwtWheel::setSingleStep (double stepSize)

Set the step size of the counter. A value <= 0.0 disables stepping

Parameters

stepSize Single step size

See also

singleStep(), setPageStepCount()

void QwtWheel::setStepAlignment (bool on)

En/Disable step alignment. When step alignment is enabled value changes initiated by user input ( mouse, keyboard, wheel ) are aligned to the multiples of the single step.

Parameters

on On/Off

See also

stepAlignment(), setSingleStep()

void QwtWheel::setTickCount (int count)

Adjust the number of grooves in the wheel's surface. The number of grooves is limited to 6 <= count <= 50. Values outside this range will be clipped. The default value is 10.

Parameters

count Number of grooves per 360 degrees

See also

tickCount()

void QwtWheel::setTotalAngle (double angle) [slot]

Set the total angle which the wheel can be turned. One full turn of the wheel corresponds to an angle of 360 degrees. A total angle of n*360 degrees means that the wheel has to be turned n times around its axis to get from the minimum value to the maximum value.

The default setting of the total angle is 360 degrees.

Parameters

angle total angle in degrees

See also

totalAngle()

void QwtWheel::setTracking (bool enable)

En/Disable tracking. If tracking is enabled (the default), the wheel emits the valueChanged() signal while the wheel is moving. If tracking is disabled, the wheel emits the valueChanged() signal only when the wheel movement is terminated.

The wheelMoved() signal is emitted regardless id tracking is enabled or not.

Parameters

enable On/Off

See also

isTracking()

void QwtWheel::setUpdateInterval (int interval)

Specify the update interval when the wheel is flying. Default and minimum value is 50 ms.

Parameters

interval Interval in milliseconds

See also

updateInterval(), setMass(), setTracking()

void QwtWheel::setValue (double value) [slot]

Set a new value without adjusting to the step raster.

Parameters

value New value

See also

value(), valueChanged()

Warning

The value is clipped when it lies outside the range.

void QwtWheel::setViewAngle (double angle) [slot]

Specify the visible portion of the wheel. You may use this function for fine-tuning the appearance of the wheel. The default value is 175 degrees. The value is limited from 10 to 175 degrees.

Parameters

angle Visible angle in degrees

See also

viewAngle(), setTotalAngle()

void QwtWheel::setWheelBorderWidth (int borderWidth)

Set the wheel border width of the wheel. The wheel border must not be smaller than 1 and is limited in dependence on the wheel's size. Values outside the allowed range will be clipped.

The wheel border defaults to 2.

Parameters

borderWidth Border width

See also

internalBorder()

void QwtWheel::setWheelWidth (int width)

Set the width of the wheel. Corresponds to the wheel height for horizontal orientation, and the wheel width for vertical orientation.

Parameters

width the wheel's width

See also

wheelWidth()

void QwtWheel::setWrapping (bool on)

En/Disable wrapping. If wrapping is true stepping up from maximum() value will take you to the minimum() value and vice versa.

Parameters

on En/Disable wrapping

See also

wrapping()

double QwtWheel::singleStep () const

Returns

Single step size

See also

setSingleStep()

QSize QwtWheel::sizeHint () const [protected], [virtual]

Returns

a size hint

bool QwtWheel::stepAlignment () const

Returns

True, when the step alignment is enabled

See also

setStepAlignment(), singleStep()

int QwtWheel::tickCount () const

Returns

Number of grooves in the wheel's surface.

See also

setTickCnt()

void QwtWheel::timerEvent (QTimerEvent * event) [protected], [virtual]

Qt timer event. The flying wheel effect is implemented using a timer

Parameters

event Timer event

See also

updateInterval()

double QwtWheel::totalAngle () const

Returns

Total angle which the wheel can be turned.

See also

setTotalAngle()

int QwtWheel::updateInterval () const

Returns

Update interval when the wheel is flying

See also

setUpdateInterval(), mass(), isTracking()

double QwtWheel::value () const

Returns

Current value of the wheel

See also

setValue(), valueChanged()

double QwtWheel::valueAt (const QPoint & pos) const [protected], [virtual]

Determine the value corresponding to a specified point

Parameters

pos Position

Returns

Value corresponding to pos

void QwtWheel::valueChanged (double value) [signal]

Notify a change of value. When tracking is enabled this signal will be emitted every time the value changes.

Parameters

value new value

See also

setTracking()

double QwtWheel::viewAngle () const

Returns

Visible portion of the wheel

See also

setViewAngle(), totalAngle()

int QwtWheel::wheelBorderWidth () const

Returns

Wheel border width

See also

setWheelBorderWidth()

void QwtWheel::wheelEvent (QWheelEvent * event) [protected], [virtual]

Handle wheel events. In/Decrement the value

Parameters

event Wheel event

void QwtWheel::wheelMoved (double value) [signal]

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

Parameters

value new value

void QwtWheel::wheelPressed () [signal]

This signal is emitted when the user presses the the wheel with the mouse

QRect QwtWheel::wheelRect () const [protected]

Returns

Rectangle of the wheel without the outer border

void QwtWheel::wheelReleased () [signal]

This signal is emitted when the user releases the mouse

int QwtWheel::wheelWidth () const

Returns

Width of the wheel

See also

setWheelWidth()

bool QwtWheel::wrapping () const

Returns

True, when wrapping is set

See also

setWrapping()

Author

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Mon Jun 1 2020 Version 6.1.5 Qwt User's Guide