QwtDial(3)

NAME
QwtDial - QwtDial class provides a rounded range control.

SYNOPSIS

#include <qwt_dial.h>

Inherits QwtAbstractSlider.

Inherited by QwtAnalogClock, and QwtCompass.

  Public Types
enum Shadow { Plain = QFrame::Plain, Raised = QFrame::Raised, Sunken = QFrame::Sunken }
Frame shadow.
enum Mode { RotateNeedle, RotateScale }
Mode controlling whether the needle or the scale is rotating.

  Public Member Functions
QwtDial (QWidget *parent=NULL)
Constructor.
virtual ~QwtDial ()
Destructor.
void setFrameShadow (Shadow)
Shadow frameShadow () const
void setLineWidth (int)
int lineWidth () const
void setMode (Mode)
Change the mode of the dial.
Mode mode () const
void setScaleArc (double minArc, double maxArc)
void setMinScaleArc (double)
double minScaleArc () const
void setMaxScaleArc (double)
double maxScaleArc () const
virtual void setOrigin (double)
Change the origin.
double origin () const
void setNeedle (QwtDialNeedle *)
const QwtDialNeedle * needle () const
QwtDialNeedle * needle ()
QRect boundingRect () const
QRect innerRect () const
virtual QRect scaleInnerRect () const
virtual QSize sizeHint () const
virtual QSize minimumSizeHint () const
void setScaleDraw (QwtRoundScaleDraw *)
QwtRoundScaleDraw * scaleDraw ()
const QwtRoundScaleDraw * scaleDraw () const

  Protected Member Functions
virtual void wheelEvent (QWheelEvent *)
virtual void paintEvent (QPaintEvent *)
virtual void changeEvent (QEvent *)
virtual void drawFrame (QPainter *)
virtual void drawContents (QPainter *) const
Draw the contents inside the frame.
virtual void drawFocusIndicator (QPainter *) const
void invalidateCache ()
virtual void drawScale (QPainter *, const QPointF &center, double radius) const
virtual void drawScaleContents (QPainter *painter, const QPointF &center, double radius) const
virtual void drawNeedle (QPainter *, const QPointF &, double radius, double direction, QPalette::ColorGroup) const
virtual double scrolledTo (const QPoint &) const
Determine the value for a new position of the slider handle.
virtual bool isScrollPosition (const QPoint &) const
Determine what to do when the user presses a mouse button.
virtual void sliderChange ()
Calling update()
virtual void scaleChange ()

  Additional Inherited Members

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 QwtAbstractSlider::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.

Often dials have to be updated very often according to values from external devices. For these high refresh rates QwtDial caches as much as possible. For derived classes it might be necessary to clear these caches manually according to attribute changes using invalidateCache().

See also:
    QwtCompass, QwtAnalogClock, QwtDialNeedle

Note:
    The controls and dials examples shows different types of dials.

    QDial is more similar to QwtKnob than to QwtDial

Member Enumeration Documentation

  enum QwtDial::Mode

Mode controlling whether the needle or the scale is rotating.

Enumerator

RotateNeedle
    The needle is rotating.

RotateScale
    The needle is fixed, the scales are rotating.

  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.

Enumerator

Plain
    QFrame::Plain.

Raised
    QFrame::Raised.

Sunken
    QFrame::Sunken.

Constructor & Destructor Documentation

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

Constructor.

Parameters:
    parent Parent widget

Create a dial widget with no needle. The scale is initialized to [ 0.0, 360.0 ] and 360 steps ( QwtAbstractSlider::setTotalSteps() ). The origin of the scale is at 90°,

The value is set to 0.0.

The default mode is QwtDial::RotateNeedle.

Member Function Documentation

  QRect QwtDial::boundingRect () const

Returns:
    bounding rectangle of the dial including the frame

See also:
    setLineWidth(), scaleInnerRect(), innerRect()

  void QwtDial::changeEvent (QEvent * event) [protected], [virtual]
Change Event handler

Parameters:
    event Change event

Invalidates internal paint caches if necessary

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

Draw the contents inside the frame. QPalette::Window is the background color outside of the frame. QPalette::Base is the background color inside the frame. QPalette::WindowText is the background color inside the scale.

Parameters:
    painter Painter

See also:
    boundingRect(), innerRect(), scaleInnerRect(), QWidget::setPalette()

  void QwtDial::drawFocusIndicator (QPainter * painter) const [protected], [virtual]
Draw the focus indicator

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 QPointF & center, double radius, double direction, QPalette::ColorGroup colorGroup) 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
    colorGroup ColorGroup

Reimplemented in QwtAnalogClock.

  void QwtDial::drawScale (QPainter * painter, const QPointF & center, double radius) const [protected], [virtual]
Draw the scale

Parameters:
    painter Painter
    center Center of the dial
    radius Radius of the scale

  void QwtDial::drawScaleContents (QPainter * painter, const QPointF & center, double 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()

  QRect QwtDial::innerRect () const

Returns:
    bounding rectangle of the circle inside the frame

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

  void QwtDial::invalidateCache () [protected]
Invalidate the internal caches used to speed up repainting

  bool QwtDial::isScrollPosition (const QPoint & pos) const [protected], [virtual]

Determine what to do when the user presses a mouse button.

Parameters:
    pos Mouse position

Return values:
    True,when the inner circle contains pos

See also:
    scrolledTo()

Implements QwtAbstractSlider.

  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

See also:
    setScaleArc()

  QSize QwtDial::minimumSizeHint () const [virtual]

Returns:
    Minimum size hint

See also:
    sizeHint()

  double QwtDial::minScaleArc () const

Returns:
    Lower limit of the scale arc

See also:
    setScaleArc()

  QwtDial::Mode QwtDial::mode () const

Returns:
    Mode of the dial.

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

  const QwtDialNeedle * QwtDial::needle () const

Returns:
    needle

See also:
    setNeedle()

  QwtDialNeedle * QwtDial::needle ()

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 * event) [protected], [virtual]
Paint the dial

Parameters:
    event Paint event

  void QwtDial::scaleChange () [protected], [virtual]
Invalidate the internal caches and call QwtAbstractSlider::scaleChange()

Reimplemented from QwtAbstractSlider.

  QwtRoundScaleDraw * QwtDial::scaleDraw ()

Returns:
    the scale draw

  const QwtRoundScaleDraw * QwtDial::scaleDraw () const

Returns:
    the scale draw

  QRect QwtDial::scaleInnerRect () const [virtual]

Returns:
    rectangle inside the scale

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

  double QwtDial::scrolledTo (const QPoint & pos) const [protected], [virtual]

Determine the value for a new position of the slider handle.

Parameters:
    pos Mouse position

Returns:
    Value for the mouse position

See also:
    isScrollPosition()

Implements QwtAbstractSlider.

  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 of the frame

Parameters:
    lineWidth Line width

See also:
    setFrameShadow()

  void QwtDial::setMaxScaleArc (double max)
Set the upper limit for the scale arc

Parameters:
    max Upper limit of the scale arc

See also:
    setScaleArc(), setMinScaleArc()

  void QwtDial::setMinScaleArc (double min)
Set the lower limit for the scale arc

Parameters:
    min Lower limit of the scale arc

See also:
    setScaleArc(), setMaxScaleArc()

  void QwtDial::setMode (Mode mode)

Change the mode of the dial.

Parameters:
    mode New mode

In case of QwtDial::RotateNeedle 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)
Set a needle for the dial

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::setScaleArc (double minArc, double maxArc)
Change the arc of the scale

Parameters:
    minArc Lower limit
    maxArc Upper limit

See also:
    minScaleArc(), maxScaleArc()

  void QwtDial::setScaleDraw (QwtRoundScaleDraw * scaleDraw)
Set an individual scale draw

The motivation for setting a scale draw is often to overload QwtRoundScaleDraw::label() to return individual tick labels.

Parameters:
    scaleDraw Scale draw

Warning:
    The previous scale draw is deleted

  QSize QwtDial::sizeHint () const [virtual]

Returns:
    Size hint

See also:
    minimumSizeHint()

  void QwtDial::wheelEvent (QWheelEvent * event) [protected], [virtual]
Wheel Event handler

Parameters:
    event Wheel event

Reimplemented from QwtAbstractSlider.

Author

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