QwtDial(3) Qwt User's Guide QwtDial(3)

QwtDial - QwtDial class provides a rounded range control.

#include <qwt_dial.h>

Inherits QwtAbstractSlider.

Inherited by QwtAnalogClock, and QwtCompass.


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.


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


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 ()

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

enum QwtDial::Mode

Mode controlling whether the needle or the scale is rotating.

Enumerator

The needle is rotating.
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

QFrame::Plain.
QFrame::Raised.
QFrame::Sunken.

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.

Returns:

bounding rectangle of the dial including the frame

See also:

setLineWidth(), scaleInnerRect(), innerRect()

Change Event handler

Parameters:

event Change event

Invalidates internal paint caches if necessary

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()

Draw the focus indicator

Parameters:

painter Painter

Draw the frame around the dial

Parameters:

painter Painter

See also:

lineWidth(), frameShadow()

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.

Draw the scale

Parameters:

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

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()

Returns:

bounding rectangle of the circle inside the frame

See also:

setLineWidth(), scaleInnerRect(), boundingRect()

Invalidate the internal caches used to speed up repainting

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.

Returns:

Line width of the frame

See also:

setLineWidth(), frameShadow(), lineWidth()

Returns:

Upper limit of the scale arc

See also:

setScaleArc()

Returns:

Minimum size hint

See also:

sizeHint()

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()

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

Returns:

Origin of the dial

See also:

setOrigin()

Paint the dial

Parameters:

event Paint event

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

Returns:

rectangle inside the scale

See also:

setLineWidth(), boundingRect(), innerRect()

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.

Sets the frame shadow value from the frame style.

Parameters:

shadow Frame shadow

See also:

setLineWidth(), QFrame::setFrameShadow()

Sets the line width of the frame

Parameters:

lineWidth Line width

See also:

setFrameShadow()

Set the upper limit for the scale arc

Parameters:

max Upper limit of the scale arc

See also:

setScaleArc(), setMinScaleArc()

Set the lower limit for the scale arc

Parameters:

min Lower limit of the scale arc

See also:

setScaleArc(), setMaxScaleArc()

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()

Set a needle for the dial

Parameters:

needle Needle

Warning:

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

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

Parameters:

origin New origin

See also:

origin()

Change the arc of the scale

Parameters:

minArc Lower limit
maxArc Upper limit

See also:

minScaleArc(), maxScaleArc()

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

Returns:

Size hint

See also:

minimumSizeHint()

Wheel Event handler

Parameters:

event Wheel event

Reimplemented from QwtAbstractSlider.

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Wed Jan 2 2019 Version 6.1.4