QwtKnob - Man Page

enum KnobStyle { Flat, Raised, Sunken, Styled }
Style of the knob surface.
enum MarkerStyle { NoMarker = -1, Tick, Triangle, Dot, Nub, Notch }
Marker type.

QwtKnob (QWidget *parent=NULL)
Constructor.
virtual ~QwtKnob ()
Destructor.
void setAlignment (Qt::Alignment)
Set the alignment of the knob.
Qt::Alignment alignment () const
void setKnobWidth (int)
Change the knob's width.
int knobWidth () const
Return the width of the knob.
void setNumTurns (int)
Set the number of turns.
int numTurns () const
void setTotalAngle (double angle)
Set the total angle by which the knob can be turned.
double totalAngle () const
void setKnobStyle (KnobStyle)
Set the knob type.
KnobStyle knobStyle () const
void setBorderWidth (int)
Set the knob's border width.
int borderWidth () const
Return the border width.
void setMarkerStyle (MarkerStyle)
Set the marker type of the knob.
MarkerStyle markerStyle () const
void setMarkerSize (int)
Set the size of the marker.
int markerSize () const
virtual QSize sizeHint () const override
virtual QSize minimumSizeHint () const override
void setScaleDraw (QwtRoundScaleDraw *)
const QwtRoundScaleDraw * scaleDraw () const
QwtRoundScaleDraw * scaleDraw ()
QRect knobRect () const

virtual void paintEvent (QPaintEvent *) override
virtual void changeEvent (QEvent *) override
virtual void drawKnob (QPainter *, const QRectF &) const
Draw the knob.
virtual void drawFocusIndicator (QPainter *) const
virtual void drawMarker (QPainter *, const QRectF &, double angle) const
Draw the marker at the knob's front.
virtual double scrolledTo (const QPoint &) const override
Determine the value for a new position of the mouse.
virtual bool isScrollPosition (const QPoint &) const override
Determine what to do when the user presses a mouse button.

Style of the knob surface. Depending on the KnobStyle the surface of the knob is filled from the brushes of the widget palette().

See also

setKnobStyle(), knobStyle()

Enumerator

Flat

Fill the knob with a brush from QPalette::Button.

Raised

Build a gradient from QPalette::Midlight and QPalette::Button.

Sunken

Build a gradient from QPalette::Midlight, QPalette::Button and QPalette::Midlight

Styled

Build a radial gradient from QPalette::Button like it is used for QDial in various Qt styles.

Definition at line 66 of file qwt_knob.h.

Marker type. The marker indicates the current value on the knob The default setting is a Notch marker.

See also

setMarkerStyle(), setMarkerSize()

Enumerator

NoMarker

Don't paint any marker.

Tick

Paint a single tick in QPalette::ButtonText color.

Triangle

Paint a triangle in QPalette::ButtonText color.

Dot

Paint a circle in QPalette::ButtonText color.

Nub

Draw a raised ellipse with a gradient build from QPalette::Light and QPalette::Mid

Notch

Draw a sunken ellipse with a gradient build from QPalette::Light and QPalette::Mid

Definition at line 95 of file qwt_knob.h.

Constructor. Construct a knob with an angle of 270°. The style is QwtKnob::Raised and the marker style is QwtKnob::Notch. The width of the knob is set to 50 pixels.

Parameters

parent Parent widget

See also

setTotalAngle()

Definition at line 103 of file qwt_knob.cpp.

Returns

Alignment of the knob inside of contentsRect()

See also

setAlignment(), knobWidth(), knobRect()

Definition at line 743 of file qwt_knob.cpp.

Handle QEvent::StyleChange and QEvent::FontChange;

Parameters

event Change event

Reimplemented from QwtAbstractScale.

Definition at line 431 of file qwt_knob.cpp.

Draw the focus indicator

Parameters

painter Painter

Definition at line 697 of file qwt_knob.cpp.

Draw the knob.

Parameters

painter painter
knobRect Bounding rectangle of the knob (without scale)

Definition at line 489 of file qwt_knob.cpp.

Draw the marker at the knob's front.

Parameters

painter Painter
rect Bounding rectangle of the knob without scale
angle Angle of the marker in degrees ( clockwise, 0 at the 12 o'clock position )

Definition at line 576 of file qwt_knob.cpp.

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

Parameters

pos Mouse position

Return values

True,when pos is inside the circle of the knob.

See also

scrolledTo()

Implements QwtAbstractSlider.

Definition at line 347 of file qwt_knob.cpp.

Calculate the bounding rectangle of the knob without the scale

Returns

Bounding rectangle of the knob

See also

knobWidth(), alignment(), QWidget::contentsRect()

Definition at line 292 of file qwt_knob.cpp.

Returns

Marker type of the knob

See also

setKnobStyle(), setBorderWidth()

Definition at line 144 of file qwt_knob.cpp.

Returns

Marker size

See also

setMarkerSize()

Definition at line 825 of file qwt_knob.cpp.

Returns

Marker type of the knob

See also

setMarkerStyle(), setMarkerSize()

Definition at line 168 of file qwt_knob.cpp.

Returns

Minimum size hint

See also

sizeHint()

Definition at line 843 of file qwt_knob.cpp.

Returns

Number of turns.

When the total angle is below 360° numTurns() is ceiled to 1.

See also

setNumTurns(), setTotalAngle(), totalAngle()

Definition at line 245 of file qwt_knob.cpp.

Repaint the knob

Parameters

event Paint event

Definition at line 451 of file qwt_knob.cpp.

Returns

the scale draw of the knob

See also

setScaleDraw()

Definition at line 281 of file qwt_knob.cpp.

Returns

the scale draw of the knob

See also

setScaleDraw()

Definition at line 272 of file qwt_knob.cpp.

Determine the value for a new position of the mouse.

Parameters

pos Mouse position

Returns

Value for the mouse position

See also

isScrollPosition()

Implements QwtAbstractSlider.

Definition at line 373 of file qwt_knob.cpp.

Set the alignment of the knob. Similar to a QLabel::alignment() the flags decide how to align the knob inside of contentsRect().

The default setting is Qt::AlignCenter

Parameters

alignment Or'd alignment flags

See also

alignment(), setKnobWidth(), knobRect()

Definition at line 730 of file qwt_knob.cpp.

Set the knob's border width.

Parameters

borderWidth new border width

Definition at line 790 of file qwt_knob.cpp.

Set the knob type.

Parameters

knobStyle Knob type

See also

knobStyle(), setBorderWidth()

Definition at line 131 of file qwt_knob.cpp.

Change the knob's width. Setting a fixed value for the diameter of the knob is helpful for aligning several knobs in a row.

Parameters

width New width

See also

knobWidth(), setAlignment()

Note

Modifies the sizePolicy()

Definition at line 759 of file qwt_knob.cpp.

Set the size of the marker. When setting a size <= 0 the marker will automatically scaled to 40% of the radius of the knob.

See also

markerSize(), markerStyle()

Definition at line 812 of file qwt_knob.cpp.

Set the marker type of the knob.

Parameters

markerStyle Marker type

See also

markerStyle(), setMarkerSize()

Definition at line 155 of file qwt_knob.cpp.

Set the number of turns. When numTurns > 1 the knob can be turned several times around its axis

• otherwise the total angle is floored to 360°.

See also

numTurns(), totalAngle(), setTotalAngle()

Definition at line 219 of file qwt_knob.cpp.

Change the scale draw of the knob

For changing the labels of the scales, it is necessary to derive from QwtRoundScaleDraw and overload QwtRoundScaleDraw::label().

See also

scaleDraw()

Definition at line 259 of file qwt_knob.cpp.

Set the total angle by which the knob can be turned.

Parameters

angle Angle in degrees.

The angle has to be between [10, 360] degrees. Angles above 360 ( so that the knob can be turned several times around its axis ) have to be set using setNumTurns().

The default angle is 270 degrees.

See also

totalAngle(), setNumTurns()

Definition at line 185 of file qwt_knob.cpp.

Returns

sizeHint()

Definition at line 833 of file qwt_knob.cpp.

Returns

the total angle

See also

setTotalAngle(), setNumTurns(), numTurns()

Definition at line 205 of file qwt_knob.cpp.