# Qwt User's Guide: QwtWheel Class Reference

Qwt User's Guide 6.0.2

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Public Slots | Public Member Functions | Protected Member Functions
QwtWheel Class Reference

`#include <qwt_wheel.h>`

Inheritance diagram for QwtWheel:
[legend]

List of all members.

## Public Slots

void | setTotalAngle (double)
void | setViewAngle (double)
Public Slots inherited from QwtAbstractSlider
virtual void | fitValue (double val)
virtual void | incValue (int steps)
virtual void | setReadOnly (bool)
virtual void | setValue (double val)

## Public Member Functions

| QwtWheel (QWidget *parent=NULL)
virtual | ~QwtWheel ()
int | borderWidth () const
double | mass () const
virtual QSize | minimumSizeHint () const
void | setBorderWidth (int)
void | setMass (double)
virtual void | setOrientation (Qt::Orientation)
void | setTickCnt (int)
void | setWheelBorderWidth (int)
void | setWheelWidth (int)
virtual QSize | sizeHint () const
int | tickCnt () const
double | totalAngle () const
double | viewAngle () const
int | wheelBorderWidth () const
QRect | wheelRect () const
int | wheelWidth () const
Public Member Functions inherited from QwtAbstractSlider
| QwtAbstractSlider (Qt::Orientation, QWidget *parent=NULL)
virtual | ~QwtAbstractSlider ()
bool | isReadOnly () const
bool | isValid () const
Qt::Orientation | orientation () const
void | setTracking (bool enable)
void | setUpdateTime (int t)
void | setValid (bool valid)
void | stopMoving ()
Public Member Functions inherited from QwtDoubleRange
| QwtDoubleRange ()
virtual | ~QwtDoubleRange ()
virtual void | incPages (int)
double | maxValue () const
double | minValue () const
int | pageSize () const
bool | periodic () const
void | setPeriodic (bool tf)
void | setRange (double vmin, double vmax, double vstep=0.0, int pagesize=1)
void | setStep (double)
double | step () const
double | value () const

## Protected Member Functions

virtual void | drawTicks (QPainter *, const QRectF &)
virtual void | drawWheelBackground (QPainter *, const QRectF &)
virtual void | getScrollMode (const QPoint &, QwtAbstractSlider::ScrollMode &, int &direction) const
virtual double | getValue (const QPoint &)
virtual void | paintEvent (QPaintEvent *)
virtual void | resizeEvent (QResizeEvent *)
virtual void | valueChange ()
Protected Member Functions inherited from QwtAbstractSlider
virtual void | keyPressEvent (QKeyEvent *e)
virtual void | mouseMoveEvent (QMouseEvent *e)
double | mouseOffset () const
virtual void | mousePressEvent (QMouseEvent *e)
virtual void | mouseReleaseEvent (QMouseEvent *e)
int | scrollMode () const
void | setMouseOffset (double)
virtual void | setPosition (const QPoint &)
virtual void | timerEvent (QTimerEvent *e)
virtual void | wheelEvent (QWheelEvent *e)
Protected Member Functions inherited from QwtDoubleRange
double | exactPrevValue () const
double | exactValue () const
double | prevValue () const
virtual void | rangeChange ()
virtual void | stepChange ()

## Additional Inherited Members

Public Types inherited from QwtAbstractSlider
enum | ScrollMode { ScrNone, ScrMouse, ScrTimer, ScrDirect, ScrPage }
Signals inherited from QwtAbstractSlider
void | sliderMoved (double value)
void | sliderPressed ()
void | sliderReleased ()
void | valueChanged (double value)

## 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 flywheel.

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
| ) |  |

protectedvirtual

Draw the Wheel's ticks

Parameters:

  painter | Painter
  rect | Rectangle for the wheel

void QwtWheel::drawWheelBackground | ( | QPainter * | painter,
|  | const QRectF & | rect
| ) |  |

protectedvirtual

Draw the Wheel's background gradient

Parameters:

  painter | Painter
  rect | Rectangle for the wheel

void QwtWheel::getScrollMode | ( | const QPoint & | p,
|  | QwtAbstractSlider::ScrollMode & | scrollMode,
|  | int & | direction
| ) |  | const

protectedvirtual

Determine the scrolling mode and direction corresponding to a specified point.

Parameters:

  p | point
  scrollMode | scrolling mode
  direction | direction

Implements QwtAbstractSlider.

double QwtWheel::mass | ( |  | ) | const

virtual

Returns:
  mass

Reimplemented from QwtAbstractSlider.

QSize QwtWheel::minimumSizeHint | ( |  | ) | const

virtual

Return a minimum size hint.

Warning:
  The return value is based on the wheel width.

void QwtWheel::paintEvent | ( | QPaintEvent * | event | ) |

protectedvirtual

Qt Paint Event.

Parameters:

  event | Paint event

void QwtWheel::resizeEvent | ( | QResizeEvent * | event | ) |

protectedvirtual

Qt Resize Event.

Parameters:

  event | Resize event

void QwtWheel::setBorderWidth | ( | int | width | ) |

Set the border width.

The border defaults to 2.

Parameters:

  width | Border width

See also:
  borderWidth()

void QwtWheel::setMass | ( | double | mass | ) |

virtual

Set the mass of the wheel.

Assigning a mass turns the wheel into a flywheel.

Parameters:

  mass | The wheel's mass

Reimplemented from QwtAbstractSlider.

void QwtWheel::setOrientation | ( | Qt::Orientation | o | ) |

virtual

Set the wheel's orientation.

Parameters:

  o | Orientation. Allowed values are Qt::Horizontal and Qt::Vertical. Defaults to Qt::Horizontal.

See also:
  QwtAbstractSlider::orientation()

Reimplemented from QwtAbstractSlider.

void QwtWheel::setTickCnt | ( | int | cnt | ) |

Adjust the number of grooves in the wheel's surface.

The number of grooves is limited to 6 <= cnt <= 50. Values outside this range will be clipped. The default value is 10.

Parameters:

  cnt | Number of grooves per 360 degrees

See also:
  tickCnt()

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::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()

QSize QwtWheel::sizeHint | ( |  | ) | const

virtual

Returns:
  a size hint

int QwtWheel::tickCnt | ( |  | ) | const

Returns:
  Number of grooves in the wheel's surface.

See also:
  setTickCnt()

double QwtWheel::totalAngle | ( |  | ) | const

Returns:
  Total angle which the wheel can be turned.

See also:
  setTotalAngle()

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()

QRect QwtWheel::wheelRect | ( |  | ) | const

Returns:
  Rectangle of the wheel without the outer border

int QwtWheel::wheelWidth | ( |  | ) | const

Returns:
  Width of the wheel

See also:
  setWheelWidth()