Qwt User's Guide: QwtDial Class Reference

# QwtDial Class Reference

QwtDial class provides a rounded range control. More...

`#include <qwt_dial.h>`

Inheritance diagram for QwtDial:
[legend]

List of all members.

## Public Types
enum | Shadow { Plain = QFrame::Plain, Raised = QFrame::Raised, Sunken = QFrame::Sunken }
enum | ScaleOptions { ScaleBackbone = 1, ScaleTicks = 2, ScaleLabel = 4 }
enum | Mode { RotateNeedle, RotateScale }
enum | Direction { Clockwise, CounterClockwise }
## Public Member Functions
| QwtDial (QWidget *parent=NULL)
virtual | ~QwtDial ()
void | setFrameShadow (Shadow)
Shadow | frameShadow () const
bool | hasVisibleBackground () const
void | showBackground (bool)
void | setLineWidth (int)
int | lineWidth () const
void | setMode (Mode)
Mode | mode () const
virtual void | setWrapping (bool)
bool | wrapping () const
virtual void | setScale (int maxMajIntv, int maxMinIntv, double step=0.0)
void | setScaleArc (double min, double max)
void | setScaleOptions (int)
void | setScaleTicks (int minLen, int medLen, int majLen, int penWidth=1)
double | minScaleArc () const
double | maxScaleArc () const
virtual void | setOrigin (double)
double | origin () const
void | setDirection (Direction)
Direction | direction () const
virtual void | setNeedle (QwtDialNeedle *)
const QwtDialNeedle * | needle () const
QwtDialNeedle * | needle ()
QRect | boundingRect () const
QRect | contentsRect () const
virtual QRect | scaleContentsRect () const
virtual QSize | sizeHint () const
virtual QSize | minimumSizeHint () const
virtual void | setScaleDraw (QwtDialScaleDraw *)
QwtDialScaleDraw * | scaleDraw ()
const QwtDialScaleDraw * | scaleDraw () const
## Protected Member Functions
virtual void | paintEvent (QPaintEvent *)
virtual void | resizeEvent (QResizeEvent *)
virtual void | keyPressEvent (QKeyEvent *)
virtual void | updateMask ()
virtual void | drawFrame (QPainter *p)
virtual void | drawContents (QPainter *) const
virtual void | drawFocusIndicator (QPainter *) const
virtual void | drawScale (QPainter *, const QPoint &center, int radius, double origin, double arcMin, double arcMax) const
virtual void | drawScaleContents (QPainter *painter, const QPoint &center, int radius) const
virtual void | drawNeedle (QPainter *, const QPoint &, int radius, double direction, QPalette::ColorGroup) const
virtual QwtText | scaleLabel (double) const
void | updateScale ()
virtual void | rangeChange ()
virtual void | valueChange ()
virtual double | getValue (const QPoint &)
virtual void | getScrollMode (const QPoint &, int &scrollMode, int &direction)
## Friends
class | QwtDialScaleDraw

## Detailed Description

QwtDial class provides a rounded range control.

QwtDial is intended as base class for dial widgets like speedometers, compass widgets, clocks ...

A dial contains a scale and a needle indicating the current value of the dial. Depending on Mode one of them is fixed and the other is rotating. If not isReadOnly() the dial can be rotated by dragging the mouse or using keyboard inputs (see keyPressEvent()). A dial might be wrapping, what means a rotation below/above one limit continues on the other limit (f.e compass). The scale might cover any arc of the dial, its values are related to the origin() of the dial.

Qwt is missing a set of good looking needles (QwtDialNeedle). Contributions are very welcome.

See also:
  QwtCompass, QwtAnalogClock, QwtDialNeedle

Note:
  The examples/dials example shows different types of dials.

## Member Enumeration Documentation

enum QwtDial::Direction

Direction of the dial

enum QwtDial::Mode

In case of RotateNeedle the needle is rotating, in case of RotateScale, the needle points to origin() and the scale is rotating.

enum QwtDial::ScaleOptions

see QwtDial::setScaleOptions

enum QwtDial::Shadow

Frame shadow.

Unfortunately it is not possible to use QFrame::Shadow as a property of a widget that is not derived from QFrame. The following enum is made for the designer only. It is safe to use QFrame::Shadow instead.

## Constructor & Destructor Documentation

QwtDial::QwtDial | ( | QWidget * | parent = `NULL` | ) | `[explicit]`

Constructor.

Parameters:

  | parent | Parent widget

Create a dial widget with no scale and no needle. The default origin is 90.0 with no valid value. It accepts mouse and keyboard inputs and has no step size. The default mode is QwtDial::RotateNeedle.

QwtDial::~QwtDial | ( |  | ) | `[virtual]`

Destructor.

## Member Function Documentation

QRect QwtDial::boundingRect | ( |  | ) | const

Returns:
  bounding rect of the dial including the frame

See also:
  setLineWidth(), scaleContentsRect(), contentsRect()

QRect QwtDial::contentsRect | ( |  | ) | const

Returns:
  bounding rect of the circle inside the frame

See also:
  setLineWidth(), scaleContentsRect(), boundingRect()

QwtDial::Direction QwtDial::direction | ( |  | ) | const

Returns:
  Direction of the dial

The default direction of a dial is QwtDial::Clockwise

See also:
  setDirection()

void QwtDial::drawContents | ( | QPainter * | painter | ) | const`[protected, virtual]`

Draw the contents inside the frame.

QColorGroup::Background is the background color outside of the frame. QColorGroup::Base is the background color inside the frame. QColorGroup::Foreground is the background color inside the scale.

Parameters:

  | painter | Painter

See also:
  boundingRect(), contentsRect(), scaleContentsRect(), QWidget::setPalette()

void QwtDial::drawFocusIndicator | ( | QPainter * | painter | ) | const`[protected, virtual]`

Draw a dotted round circle, if !isReadOnly()

Parameters:

  | painter | Painter

void QwtDial::drawFrame | ( | QPainter * | painter | ) | `[protected, virtual]`

Draw the frame around the dial

Parameters:

  | painter | Painter

See also:
  lineWidth(), frameShadow()

void QwtDial::drawNeedle | ( | QPainter * | painter,
|  | const QPoint & | center,
|  | int | radius,
|  | double | direction,
|  | QPalette::ColorGroup | cg |
| ) |  |  | const`[protected, virtual]`

Draw the needle

Parameters:

  | painter | Painter
  | center | Center of the dial
  | radius | Length for the needle
  | direction | Direction of the needle in degrees, counter clockwise
  | cg | ColorGroup

Reimplemented in QwtAnalogClock.

void QwtDial::drawScale | ( | QPainter * | painter,
|  | const QPoint & | center,
|  | int | radius,
|  | double | origin,
|  | double | minArc,
|  | double | maxArc |
| ) |  |  | const`[protected, virtual]`

Draw the scale

Parameters:

  | painter | Painter
  | center | Center of the dial
  | radius | Radius of the scale
  | origin | Origin of the scale
  | minArc | Minimum of the arc
  | maxArc | Minimum of the arc

See also:
  QwtAbstractScaleDraw::setAngleRange()

void QwtDial::drawScaleContents | ( | QPainter * | painter,
|  | const QPoint & | center,
|  | int | radius |
| ) |  |  | const`[protected, virtual]`

Draw the contents inside the scale

Paints nothing.

Parameters:

  | painter | Painter
  | center | Center of the contents circle
  | radius | Radius of the contents circle

Reimplemented in QwtCompass.

QwtDial::Shadow QwtDial::frameShadow | ( |  | ) | const

Returns:
  Frame shadow /sa setFrameShadow(), lineWidth(), QFrame::frameShadow

void QwtDial::getScrollMode | ( | const QPoint & | pos,
|  | int & | scrollMode,
|  | int & | direction |
| ) |  |  | `[protected, virtual]`

See QwtAbstractSlider::getScrollMode()

Parameters:

  | pos | point where the mouse was pressed

Return values:

  | scrollMode | The scrolling mode
  | direction | direction: 1, 0, or -1.

See also:
  QwtAbstractSlider::getScrollMode()

Implements QwtAbstractSlider.

double QwtDial::getValue | ( | const QPoint & | pos | ) | `[protected, virtual]`

Find the value for a given position

Parameters:

  | pos | Position

Returns:
  Value

Implements QwtAbstractSlider.

bool QwtDial::hasVisibleBackground | ( |  | ) | const

true when the area outside of the frame is visible

See also:
  showBackground(), setMask()

void QwtDial::keyPressEvent | ( | QKeyEvent * | event | ) | `[protected, virtual]`

Handles key events

- Key_Down, KeyLeft
  Decrement by 1
- Key_Prior
  Decrement by pageSize()
- Key_Home
  Set the value to minValue()

- Key_Up, KeyRight
  Increment by 1
- Key_Next
  Increment by pageSize()
- Key_End
  Set the value to maxValue()

Parameters:

  | event | Key event

See also:
  isReadOnly()

Reimplemented from QwtAbstractSlider.

Reimplemented in QwtCompass.

int QwtDial::lineWidth | ( |  | ) | const

Returns:
  Line width of the frame

See also:
  setLineWidth(), frameShadow(), lineWidth()

double QwtDial::maxScaleArc | ( |  | ) | const

Returns:
  Upper limit of the scale arc

QSize QwtDial::minimumSizeHint | ( |  | ) | const`[virtual]`

Return a minimum size hint.

Warning:
  The return value of QwtDial::minimumSizeHint() depends on the font and the scale.

double QwtDial::minScaleArc | ( |  | ) | const

Returns:
  Lower limit of the scale arc

QwtDial::Mode QwtDial::mode | ( |  | ) | const

Returns:
  mode of the dial.

The value of the dial is indicated by the difference between the origin and the direction of the needle. In case of QwtDial::RotateNeedle the scale arc is fixed to the origin() and the needle is rotating, in case of QwtDial::RotateScale, the needle points to origin() and the scale is rotating.

The default mode is QwtDial::RotateNeedle.

See also:
  setMode(), origin(), setScaleArc(), value()

QwtDialNeedle * QwtDial::needle | ( |  | ) |

Returns:
  needle

See also:
  setNeedle()

const QwtDialNeedle * QwtDial::needle | ( |  | ) | const

Returns:
  needle

See also:
  setNeedle()

double QwtDial::origin | ( |  | ) | const

The origin is the angle where scale and needle is relative to.

Returns:
  Origin of the dial

See also:
  setOrigin()

void QwtDial::paintEvent | ( | QPaintEvent * | e | ) | `[protected, virtual]`

Paint the dial

Parameters:

  | e | Paint event

void QwtDial::rangeChange | ( |  | ) | `[protected, virtual]`

QwtDoubleRange update hook.

Reimplemented from QwtDoubleRange.

void QwtDial::resizeEvent | ( | QResizeEvent * | e | ) | `[protected, virtual]`

Resize the dial widget

Parameters:

  | e | Resize event

QRect QwtDial::scaleContentsRect | ( |  | ) | const`[virtual]`

Returns:
  rect inside the scale

See also:
  setLineWidth(), boundingRect(), contentsRect()

const QwtDialScaleDraw * QwtDial::scaleDraw | ( |  | ) | const

Return the scale draw.

QwtDialScaleDraw * QwtDial::scaleDraw | ( |  | ) |

Return the scale draw.

QwtText QwtDial::scaleLabel | ( | double | value | ) | const`[protected, virtual]`

Find the label for a value

Parameters:

  | value | Value

Returns:
  label

Reimplemented in QwtAnalogClock, and QwtCompass.

void QwtDial::setDirection | ( | Direction | direction | ) |

Set the direction of the dial (clockwise/counterclockwise)

Direction direction

See also:
  direction()

void QwtDial::setFrameShadow | ( | Shadow | shadow | ) |

Sets the frame shadow value from the frame style.

Parameters:

  | shadow | Frame shadow

See also:
  setLineWidth(), QFrame::setFrameShadow()

void QwtDial::setLineWidth | ( | int | lineWidth | ) |

Sets the line width

Parameters:

  | lineWidth | Line width

See also:
  setFrameShadow()

void QwtDial::setMode | ( | Mode | mode | ) |

Change the mode of the meter.

Parameters:

  | mode | New mode

The value of the meter is indicated by the difference between north of the scale and the direction of the needle. In case of QwtDial::RotateNeedle north is pointing to the origin() and the needle is rotating, in case of QwtDial::RotateScale, the needle points to origin() and the scale is rotating.

The default mode is QwtDial::RotateNeedle.

See also:
  mode(), setValue(), setOrigin()

void QwtDial::setNeedle | ( | QwtDialNeedle * | needle | ) | `[virtual]`

Set a needle for the dial

Qwt is missing a set of good looking needles. Contributions are very welcome.

Parameters:

  | needle | Needle

Warning:
  The needle will be deleted, when a different needle is set or in ~QwtDial()

void QwtDial::setOrigin | ( | double | origin | ) | `[virtual]`

Change the origin.

The origin is the angle where scale and needle is relative to.

Parameters:

  | origin | New origin

See also:
  origin()

void QwtDial::setScale | ( | int | maxMajIntv,
|  | int | maxMinIntv,
|  | double | step = `0.0` |
| ) |  |  | `[virtual]`

Change the intervals of the scale

See also:
  QwtAbstractScaleDraw::setScale()

void QwtDial::setScaleArc | ( | double | minArc,
|  | double | maxArc |
| ) |  |  |

Change the arc of the scale

Parameters:

  | minArc | Lower limit
  | maxArc | Upper limit

void QwtDial::setScaleDraw | ( | QwtDialScaleDraw * | scaleDraw | ) | `[virtual]`

Set an individual scale draw

Parameters:

  | scaleDraw | Scale draw

Warning:
  The previous scale draw is deleted

void QwtDial::setScaleOptions | ( | int | options | ) |

A wrapper method for accessing the scale draw.

- options == 0
  No visible scale: setScaleDraw(NULL)
- options & ScaleBackbone
  En/disable the backbone of the scale.
- options & ScaleTicks
  En/disable the ticks of the scale.
- options & ScaleLabel
  En/disable scale labels

See also:
  QwtAbstractScaleDraw::enableComponent()

void QwtDial::setScaleTicks | ( | int | minLen,
|  | int | medLen,
|  | int | majLen,
|  | int | penWidth = `1` |
| ) |  |  |

Assign length and width of the ticks

Parameters:

  | minLen | Length of the minor ticks
  | medLen | Length of the medium ticks
  | majLen | Length of the major ticks
  | penWidth | Width of the pen for all ticks

See also:
  QwtAbstractScaleDraw::setTickLength(), QwtDialScaleDraw::setPenWidth()

void QwtDial::setWrapping | ( | bool | wrapping | ) | `[virtual]`

Sets whether it is possible to step the value from the highest value to the lowest value and vice versa to on.

Parameters:

  | wrapping | en/disables wrapping

See also:
  wrapping(), QwtDoubleRange::periodic()

Note:
  The meaning of wrapping is like the wrapping property of QSpinBox, but not like it is used in QDial.

void QwtDial::showBackground | ( | bool | show | ) |

Show/Hide the area outside of the frame

Parameters:

  | show | Show if true, hide if false

See also:
  hasVisibleBackground(), setMask()

Warning:
  When QwtDial is a toplevel widget the window border might disappear too.

QSize QwtDial::sizeHint | ( |  | ) | const`[virtual]`

Returns:
  Size hint

void QwtDial::updateMask | ( |  | ) | `[protected, virtual]`

Update the mask of the dial.

In case of "hasVisibleBackground() == false", the backgound is transparent by a mask.

See also:
  showBackground(), hasVisibleBackground()

void QwtDial::updateScale | ( |  | ) | `[protected]`

Update the scale with the current attributes

See also:
  setScale()

void QwtDial::valueChange | ( |  | ) | `[protected, virtual]`

QwtDoubleRange update hook.

Reimplemented from QwtAbstractSlider.

bool QwtDial::wrapping | ( |  | ) | const

wrapping() holds whether it is possible to step the value from the highest value to the lowest value and vice versa.

See also:
  setWrapping(), QwtDoubleRange::setPeriodic()

Note:
  The meaning of wrapping is like the wrapping property of QSpinBox, but not like it is used in QDial.