QwtKnob(3) Qwt User's Guide QwtKnob(3) NAME QwtKnob - The Knob Widget. SYNOPSIS #include Inherits QwtAbstractSlider. Public Types enum KnobStyle { Flat, Raised, Sunken, Styled } Style of the knob surface. enum MarkerStyle { NoMarker = -1, Tick, Triangle, Dot, Nub, Notch } Marker type. Public Member Functions 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 Protected Member Functions 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. Additional Inherited Members Detailed Description The Knob Widget. The QwtKnob widget imitates look and behavior of a volume knob on a radio. It looks similar to QDial - not to QwtDial. The value range of a knob might be divided into several turns. The layout of the knob depends on the knobWidth(). o width > 0 The diameter of the knob is fixed and the knob is aligned according to the alignment() flags inside of the contentsRect(). o width <= 0 The knob is extended to the minimum of width/height of the contentsRect() and aligned in the other direction according to alignment(). Setting a fixed knobWidth() is helpful to align several knobs with different scale labels. Definition at line 42 of file qwt_knob.h. Member Enumeration Documentation enum QwtKnob::KnobStyle 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. enum QwtKnob::MarkerStyle 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 & Destructor Documentation QwtKnob::QwtKnob (QWidget * parent = NULL) [explicit] 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. Member Function Documentation Qt::Alignment QwtKnob::alignment () const Returns Alignment of the knob inside of contentsRect() See also setAlignment(), knobWidth(), knobRect() Definition at line 743 of file qwt_knob.cpp. void QwtKnob::changeEvent (QEvent * event) [override], [protected], [virtual] Handle QEvent::StyleChange and QEvent::FontChange; Parameters event Change event Reimplemented from QwtAbstractScale. Definition at line 431 of file qwt_knob.cpp. void QwtKnob::drawFocusIndicator (QPainter * painter) const [protected], [virtual] Draw the focus indicator Parameters painter Painter Definition at line 697 of file qwt_knob.cpp. void QwtKnob::drawKnob (QPainter * painter, const QRectF & knobRect) const [protected], [virtual] Draw the knob. Parameters painter painter knobRect Bounding rectangle of the knob (without scale) Definition at line 489 of file qwt_knob.cpp. void QwtKnob::drawMarker (QPainter * painter, const QRectF & rect, double angle) const [protected], [virtual] 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. bool QwtKnob::isScrollPosition (const QPoint & pos) const [override], [protected], [virtual] 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. QRect QwtKnob::knobRect () const 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. QwtKnob::KnobStyle QwtKnob::knobStyle () const Returns Marker type of the knob See also setKnobStyle(), setBorderWidth() Definition at line 144 of file qwt_knob.cpp. int QwtKnob::markerSize () const Returns Marker size See also setMarkerSize() Definition at line 825 of file qwt_knob.cpp. QwtKnob::MarkerStyle QwtKnob::markerStyle () const Returns Marker type of the knob See also setMarkerStyle(), setMarkerSize() Definition at line 168 of file qwt_knob.cpp. QSize QwtKnob::minimumSizeHint () const [override], [virtual] Returns Minimum size hint See also sizeHint() Definition at line 843 of file qwt_knob.cpp. int QwtKnob::numTurns () const 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. void QwtKnob::paintEvent (QPaintEvent * event) [override], [protected], [virtual] Repaint the knob Parameters event Paint event Definition at line 451 of file qwt_knob.cpp. QwtRoundScaleDraw * QwtKnob::scaleDraw () Returns the scale draw of the knob See also setScaleDraw() Definition at line 281 of file qwt_knob.cpp. const QwtRoundScaleDraw * QwtKnob::scaleDraw () const Returns the scale draw of the knob See also setScaleDraw() Definition at line 272 of file qwt_knob.cpp. double QwtKnob::scrolledTo (const QPoint & pos) const [override], [protected], [virtual] 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. void QwtKnob::setAlignment (Qt::Alignment alignment) 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. void QwtKnob::setBorderWidth (int borderWidth) Set the knob's border width. Parameters borderWidth new border width Definition at line 790 of file qwt_knob.cpp. void QwtKnob::setKnobStyle (KnobStyle knobStyle) Set the knob type. Parameters knobStyle Knob type See also knobStyle(), setBorderWidth() Definition at line 131 of file qwt_knob.cpp. void QwtKnob::setKnobWidth (int width) 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. void QwtKnob::setMarkerSize (int size) 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. void QwtKnob::setMarkerStyle (MarkerStyle markerStyle) Set the marker type of the knob. Parameters markerStyle Marker type See also markerStyle(), setMarkerSize() Definition at line 155 of file qwt_knob.cpp. void QwtKnob::setNumTurns (int numTurns) Set the number of turns. When numTurns > 1 the knob can be turned several times around its axis o otherwise the total angle is floored to 360. See also numTurns(), totalAngle(), setTotalAngle() Definition at line 219 of file qwt_knob.cpp. void QwtKnob::setScaleDraw (QwtRoundScaleDraw * scaleDraw) 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. void QwtKnob::setTotalAngle (double angle) 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. QSize QwtKnob::sizeHint () const [override], [virtual] Returns sizeHint() Definition at line 833 of file qwt_knob.cpp. double QwtKnob::totalAngle () const Returns the total angle See also setTotalAngle(), setNumTurns(), numTurns() Definition at line 205 of file qwt_knob.cpp. Author Generated automatically by Doxygen for Qwt User's Guide from the source code. Version 6.2.0 Sun Jul 18 2021 QwtKnob(3)