--- name: "QwtPicker" section: "3" platform: "linux" package: "libqwt-doc" version: "6.1.4-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/QwtPicker" --- # QwtPicker(3) QwtPicker provides selections on a widget. ## NAME QwtPicker - **QwtPicker** provides selections on a widget. ## SYNOPSIS `#include ` Inherits QObject, and **QwtEventPattern**. Inherited by **QwtPlotPicker**. ### Public Types enum **RubberBand** { **NoRubberBand** = 0, **HLineRubberBand**, **VLineRubberBand**, **CrossRubberBand**, **RectRubberBand**, **EllipseRubberBand**, **PolygonRubberBand**, **UserRubberBand** = 100 }\ enum **DisplayMode** { **AlwaysOff**, **AlwaysOn**, **ActiveOnly** }\ Display mode. enum **ResizeMode** { **Stretch**, **KeepSize** }\ ### Public Slots void **setEnabled** (bool)\ En/disable the picker. ### Signals void **activated** (bool on)\ void **selected** (const QPolygon &polygon)\ void **appended** (const QPoint &pos)\ void **moved** (const QPoint &pos)\ void **removed** (const QPoint &pos)\ void **changed** (const QPolygon &**selection**)\ ### Public Member Functions **QwtPicker** (QWidget \*parent)\ **QwtPicker** (**RubberBand** **rubberBand**, **DisplayMode** **trackerMode**, QWidget \*)\ virtual **~QwtPicker** ()\ Destructor. void **setStateMachine** (**QwtPickerMachine** \*)\ const **QwtPickerMachine** \* **stateMachine** () const\ **QwtPickerMachine** \* **stateMachine** ()\ void **setRubberBand** (**RubberBand**)\ **RubberBand** **rubberBand** () const\ void **setTrackerMode** (**DisplayMode**)\ Set the display mode of the tracker. **DisplayMode** **trackerMode** () const\ void **setResizeMode** (**ResizeMode**)\ Set the resize mode. **ResizeMode** **resizeMode** () const\ void **setRubberBandPen** (const QPen &)\ QPen **rubberBandPen** () const\ void **setTrackerPen** (const QPen &)\ QPen **trackerPen** () const\ void **setTrackerFont** (const QFont &)\ QFont **trackerFont** () const\ bool **isEnabled** () const\ bool **isActive** () const\ virtual bool **eventFilter** (QObject \*, QEvent \*)\ Event filter. QWidget \* **parentWidget** ()\ Return the parent widget, where the selection happens. const QWidget \* **parentWidget** () const\ Return the parent widget, where the selection happens. virtual QPainterPath **pickArea** () const\ virtual void **drawRubberBand** (QPainter \*) const\ virtual void **drawTracker** (QPainter \*) const\ virtual QRegion **rubberBandMask** () const\ virtual **QwtText** **trackerText** (const QPoint &pos) const\ Return the label for a position. QPoint **trackerPosition** () const\ virtual QRect **trackerRect** (const QFont &) const\ QPolygon **selection** () const\ ### Protected Member Functions virtual QPolygon **adjustedPoints** (const QPolygon &) const\ Map the **pickedPoints()** into a **selection()** virtual void **transition** (const QEvent \*)\ virtual void **begin** ()\ virtual void **append** (const QPoint &)\ virtual void **move** (const QPoint &)\ virtual void **remove** ()\ virtual bool **end** (bool ok=true)\ Close a selection setting the state to inactive. virtual bool **accept** (QPolygon &) const\ Validate and fix up the selection. virtual void **reset** ()\ virtual void **widgetMousePressEvent** (QMouseEvent \*)\ virtual void **widgetMouseReleaseEvent** (QMouseEvent \*)\ virtual void **widgetMouseDoubleClickEvent** (QMouseEvent \*)\ virtual void **widgetMouseMoveEvent** (QMouseEvent \*)\ virtual void **widgetWheelEvent** (QWheelEvent \*)\ virtual void **widgetKeyPressEvent** (QKeyEvent \*)\ virtual void **widgetKeyReleaseEvent** (QKeyEvent \*)\ virtual void **widgetEnterEvent** (QEvent \*)\ virtual void **widgetLeaveEvent** (QEvent \*)\ virtual void **stretchSelection** (const QSize &oldSize, const QSize &newSize)\ virtual void **updateDisplay** ()\ Update the state of rubber band and tracker label. const **QwtWidgetOverlay** \* **rubberBandOverlay** () const\ const **QwtWidgetOverlay** \* **trackerOverlay** () const\ const QPolygon & **pickedPoints** () const\ ## Detailed Description **QwtPicker** provides selections on a widget. **QwtPicker** filters all enter, leave, mouse and keyboard events of a widget and translates them into an array of selected points. The way how the points are collected depends on type of state machine that is connected to the picker. Qwt offers a couple of predefined state machines for selecting: - • Nothing\ \ **QwtPickerTrackerMachine** - • Single points\ \ **QwtPickerClickPointMachine**, **QwtPickerDragPointMachine** - • Rectangles\ \ **QwtPickerClickRectMachine**, **QwtPickerDragRectMachine** - • Polygons\ \ **QwtPickerPolygonMachine** While these state machines cover the most common ways to collect points it is also possible to implement individual machines as well. **QwtPicker** translates the picked points into a selection using the **adjustedPoints()** method. **adjustedPoints()** is intended to be reimplemented to fix up the selection according to application specific requirements. (F.e. when an application accepts rectangles of a fixed aspect ratio only.) Optionally **QwtPicker** support the process of collecting points by a rubber band and tracker displaying a text for the current mouse position. **Example** ``` #include #include QwtPicker *picker = new QwtPicker(widget); picker->setStateMachine(new QwtPickerDragRectMachine); picker->setTrackerMode(QwtPicker::ActiveOnly); picker->setRubberBand(QwtPicker::RectRubberBand); ``` The state machine triggers the following commands: - • **begin()**\ \ Activate/Initialize the selection. - • **append()**\ \ Add a new point - • **move()** \ \ Change the position of the last point. - • **remove()**\ \ Remove the last point. - • **end()**\ \ Terminate the selection and call accept to validate the picked points. The picker is active (**isActive()**), between **begin()** and **end()**. In active state the rubber band is displayed, and the tracker is visible in case of trackerMode is ActiveOnly or AlwaysOn. The cursor can be moved using the arrow keys. All selections can be aborted using the abort key. (**QwtEventPattern::KeyPatternCode**) **Warning:** In case of QWidget::NoFocus the focus policy of the observed widget is set to QWidget::WheelFocus and mouse tracking will be manipulated while the picker is active, or if **trackerMode()** is AlwayOn. ## Member Enumeration Documentation ### enum QwtPicker::DisplayMode Display mode. **See also:** **setTrackerMode()**, **trackerMode()**, **isActive()** **Enumerator** - *AlwaysOff* *Display never.* - *AlwaysOn* *Display always.* - *ActiveOnly* *Display only when the selection is active.* ### enum QwtPicker::ResizeMode *Controls what to do with the selected points of an active selection when the observed widget is resized.* *The default value is* **QwtPicker::Stretch***.* **See also:** **setResizeMode()** **Enumerator** - *Stretch* *All points are scaled according to the new size,.* - *KeepSize* *All points remain unchanged.* ### enum QwtPicker::RubberBand *Rubber band style* *The default value is* **QwtPicker::NoRubberBand***.* **See also:** **setRubberBand()***,* **rubberBand()** **Enumerator** - *NoRubberBand* *No rubberband.* - *HLineRubberBand* *A horizontal line ( only for* **QwtPickerMachine::PointSelection** *)* - *VLineRubberBand* *A vertical line ( only for* **QwtPickerMachine::PointSelection** *)* - *CrossRubberBand* *A crosshair ( only for* **QwtPickerMachine::PointSelection** *)* - *RectRubberBand* *A rectangle ( only for* **QwtPickerMachine::RectSelection** *)* - *EllipseRubberBand* *An ellipse ( only for* **QwtPickerMachine::RectSelection** *)* - *PolygonRubberBand* *A polygon ( only for* **QwtPickerMachine::PolygonSelection** *)* - *UserRubberBand* *Values \>= UserRubberBand can be used to define additional rubber bands.* ## Constructor & Destructor Documentation ### QwtPicker::QwtPicker (QWidget \* parent)` [explicit]` *Constructor* *Creates an picker that is enabled, but without a state machine. rubber band and tracker are disabled.* **Parameters:** *parent Parent widget, that will be observed* ### QwtPicker::QwtPicker (RubberBand rubberBand, DisplayMode trackerMode, QWidget \* parent)` [explicit]` *Constructor* **Parameters:** *rubberBand Rubber band style* \ *trackerMode Tracker mode* \ *parent Parent widget, that will be observed* ## Member Function Documentation ### bool QwtPicker::accept (QPolygon & selection) const` [protected]`, ` [virtual]` *Validate and fix up the selection. Accepts all selections unmodified* **Parameters:** *selection Selection to validate and fix up* **Returns:** *true, when accepted, false otherwise* *Reimplemented in* **QwtPlotZoomer***.* ### void QwtPicker::activated (bool on)` [signal]` *A signal indicating, when the picker has been activated. Together with* **setEnabled()** *it can be used to implement selections with more than one picker.* **Parameters:** *on True, when the picker has been activated* ### QPolygon QwtPicker::adjustedPoints (const QPolygon & points) const` [protected]`, ` [virtual]` *Map the* **pickedPoints()** *into a* **selection()** **adjustedPoints()** *maps the points, that have been collected on the* **parentWidget()** *into a* **selection()***. The default implementation simply returns the points unmodified.* *The reason, why a* **selection()** *differs from the picked points depends on the application requirements. F.e. :* - • *A rectangular selection might need to have a specific aspect ratio only.* - • *A selection could accept non intersecting polygons only.* - • *...* *The example below is for a rectangular selection, where the first point is the center of the selected rectangle.* **Example** ``` QPolygon MyPicker::adjustedPoints( const QPolygon &points ) const { QPolygon adjusted; if ( points.size() == 2 ) { const int width = qAbs( points[1].x() - points[0].x() ); const int height = qAbs( points[1].y() - points[0].y() ); QRect rect( 0, 0, 2 * width, 2 * height ); rect.moveCenter( points[0] ); adjusted += rect.topLeft(); adjusted += rect.bottomRight(); } return adjusted; } ``` **Parameters:** *points Selected points* **Returns:** *Selected points unmodified* ### void QwtPicker::append (const QPoint & pos)` [protected]`, ` [virtual]` *Append a point to the selection and update rubber band and tracker. The* **appended()** *signal is emitted.* **Parameters:** *pos Additional point* **See also:** **isActive()***,* **begin()***,* **end()***,* **move()***,* **appended()** *Reimplemented in* **QwtPlotPicker***.* ### void QwtPicker::appended (const QPoint & pos)` [signal]` *A signal emitted when a point has been appended to the selection* **Parameters:** *pos Position of the appended point.* **See also:** **append()***.* **moved()** ### void QwtPicker::begin ()` [protected]`, ` [virtual]` *Open a selection setting the state to active* **See also:** **isActive()***,* **end()***,* **append()***,* **move()** *Reimplemented in* **QwtPlotZoomer***.* ### void QwtPicker::changed (const QPolygon & selection)` [signal]` *A signal emitted when the active selection has been changed. This might happen when the observed widget is resized.* **Parameters:** *selection Changed selection* **See also:** **stretchSelection()** ### void QwtPicker::drawRubberBand (QPainter \* painter) const` [virtual]` *Draw a rubber band, depending on* **rubberBand()** **Parameters:** *painter Painter, initialized with a clip region* **See also:** **rubberBand()***,* **RubberBand** ### void QwtPicker::drawTracker (QPainter \* painter) const` [virtual]` *Draw the tracker* **Parameters:** *painter Painter* **See also:** **trackerRect()***,* **trackerText()** ### bool QwtPicker::end (bool ok = `true`)` [protected]`, ` [virtual]` *Close a selection setting the state to inactive. The selection is validated and maybe fixed by* **accept()***.* **Parameters:** *ok If true, complete the selection and emit a selected signal otherwise discard the selection.* **Returns:** *true if the selection is accepted, false otherwise* **See also:** **isActive()***,* **begin()***,* **append()***,* **move()***,* **selected()***,* **accept()** *Reimplemented in* **QwtPlotZoomer***, and* **QwtPlotPicker***.* ### bool QwtPicker::eventFilter (QObject \* object, QEvent \* event)` [virtual]` *Event filter. When* **isEnabled()** *is true all events of the observed widget are filtered. Mouse and keyboard events are translated into widgetMouse- and widgetKey- and widgetWheel-events. Paint and Resize events are handled to keep rubber band and tracker up to date.* **Parameters:** *object Object to be filtered* \ *event Event* **Returns:** *Always false.* **See also:** **widgetEnterEvent()***,* **widgetLeaveEvent()***,* **widgetMousePressEvent()***,* **widgetMouseReleaseEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetMouseMoveEvent()***,* **widgetWheelEvent()***,* **widgetKeyPressEvent()***,* **widgetKeyReleaseEvent()***, QObject::installEventFilter(), QObject::event()* ### bool QwtPicker::isActive () const *A picker is active between* **begin()** *and* **end()***.* **Returns:** *true if the selection is active.* ### bool QwtPicker::isEnabled () const **Returns:** *true when enabled, false otherwise* **See also:** **setEnabled()***,* **eventFilter()** ### void QwtPicker::move (const QPoint & pos)` [protected]`, ` [virtual]` *Move the last point of the selection The* **moved()** *signal is emitted.* **Parameters:** *pos New position* **See also:** **isActive()***,* **begin()***,* **end()***,* **append()** *Reimplemented in* **QwtPlotPicker***.* ### void QwtPicker::moved (const QPoint & pos)` [signal]` *A signal emitted whenever the last appended point of the selection has been moved.* **Parameters:** *pos Position of the moved last point of the selection.* **See also:** **move()***,* **appended()** ### QPainterPath QwtPicker::pickArea () const` [virtual]` *Find the area of the observed widget, where selection might happen.* **Returns:** **parentWidget()***-\>contentsRect()* ### const QPolygon & QwtPicker::pickedPoints () const` [protected]` *Return the points, that have been collected so far. The* **selection()** *is calculated from the* **pickedPoints()** *in* **adjustedPoints()***.* **Returns:** *Picked points* ### void QwtPicker::remove ()` [protected]`, ` [virtual]` *Remove the last point of the selection The* **removed()** *signal is emitted.* **See also:** **isActive()***,* **begin()***,* **end()***,* **append()***,* **move()** ### void QwtPicker::removed (const QPoint & pos)` [signal]` *A signal emitted whenever the last appended point of the selection has been removed.* **Parameters:** *pos Position of the point, that has been removed* **See also:** **remove()***,* **appended()** ### void QwtPicker::reset ()` [protected]`, ` [virtual]` *Reset the state machine and terminate ( end(false) ) the selection* ### QwtPicker::ResizeMode QwtPicker::resizeMode () const **Returns:** *Resize mode* **See also:** **setResizeMode()***,* **ResizeMode** ### QwtPicker::RubberBand QwtPicker::rubberBand () const **Returns:** *Rubber band style* **See also:** **setRubberBand()***,* **RubberBand***,* **rubberBandPen()** ### QRegion QwtPicker::rubberBandMask () const` [virtual]` *Calculate the mask for the rubber band overlay* **Returns:** *Region for the mask* **See also:** *QWidget::setMask()* ### const QwtWidgetOverlay \* QwtPicker::rubberBandOverlay () const` [protected]` **Returns:** *Overlay displaying the rubber band* ### QPen QwtPicker::rubberBandPen () const **Returns:** *Rubber band pen* **See also:** **setRubberBandPen()***,* **rubberBand()** ### void QwtPicker::selected (const QPolygon & polygon)` [signal]` *A signal emitting the selected points, at the end of a selection.* **Parameters:** *polygon Selected points* ### QPolygon QwtPicker::selection () const **Returns:** *Selected points* **See also:** **pickedPoints()***,* **adjustedPoints()** ### void QwtPicker::setEnabled (bool enabled)` [slot]` *En/disable the picker. When enabled is true an event filter is installed for the observed widget, otherwise the event filter is removed.* **Parameters:** *enabled true or false* **See also:** **isEnabled()***,* **eventFilter()** ### void QwtPicker::setResizeMode (ResizeMode mode) *Set the resize mode. The resize mode controls what to do with the selected points of an active selection when the observed widget is resized.* *Stretch means the points are scaled according to the new size, KeepSize means the points remain unchanged.* *The default mode is Stretch.* **Parameters:** *mode Resize mode* **See also:** **resizeMode()***,* **ResizeMode** ### void QwtPicker::setRubberBand (RubberBand rubberBand) *Set the rubber band style* **Parameters:** *rubberBand Rubber band style The default value is NoRubberBand.* **See also:** **rubberBand()***,* **RubberBand***,* **setRubberBandPen()** ### void QwtPicker::setRubberBandPen (const QPen & pen) *Set the pen for the rubberband* **Parameters:** *pen Rubber band pen* **See also:** **rubberBandPen()***,* **setRubberBand()** ### void QwtPicker::setStateMachine (QwtPickerMachine \* stateMachine) *Set a state machine and delete the previous one* **Parameters:** *stateMachine State machine* **See also:** **stateMachine()** ### void QwtPicker::setTrackerFont (const QFont & font) *Set the font for the tracker* **Parameters:** *font Tracker font* **See also:** **trackerFont()***,* **setTrackerMode()***,* **setTrackerPen()** ### void QwtPicker::setTrackerMode (DisplayMode mode) *Set the display mode of the tracker. A tracker displays information about current position of the cursor as a string. The display mode controls if the tracker has to be displayed whenever the observed widget has focus and cursor (AlwaysOn), never (AlwaysOff), or only when the selection is active (ActiveOnly).* **Parameters:** *mode Tracker display mode* **Warning:** *In case of AlwaysOn, mouseTracking will be enabled for the observed widget.* **See also:** **trackerMode()***,* **DisplayMode** ### void QwtPicker::setTrackerPen (const QPen & pen) *Set the pen for the tracker* **Parameters:** *pen Tracker pen* **See also:** **trackerPen()***,* **setTrackerMode()***,* **setTrackerFont()** ### const QwtPickerMachine \* QwtPicker::stateMachine () const **Returns:** *Assigned state machine* **See also:** **setStateMachine()** ### QwtPickerMachine \* QwtPicker::stateMachine () **Returns:** *Assigned state machine* **See also:** **setStateMachine()** ### void QwtPicker::stretchSelection (const QSize & oldSize, const QSize & newSize)` [protected]`, ` [virtual]` *Scale the selection by the ratios of oldSize and newSize The* **changed()** *signal is emitted.* **Parameters:** *oldSize Previous size* \ *newSize Current size* **See also:** **ResizeMode***,* **setResizeMode()***,* **resizeMode()** ### QFont QwtPicker::trackerFont () const **Returns:** *Tracker font* **See also:** **setTrackerFont()***,* **trackerMode()***,* **trackerPen()** ### QwtPicker::DisplayMode QwtPicker::trackerMode () const **Returns:** *Tracker display mode* **See also:** **setTrackerMode()***,* **DisplayMode** ### const QwtWidgetOverlay \* QwtPicker::trackerOverlay () const` [protected]` **Returns:** *Overlay displaying the tracker text* ### QPen QwtPicker::trackerPen () const **Returns:** *Tracker pen* **See also:** **setTrackerPen()***,* **trackerMode()***,* **trackerFont()** ### QPoint QwtPicker::trackerPosition () const **Returns:** *Current position of the tracker* ### QRect QwtPicker::trackerRect (const QFont & font) const` [virtual]` *Calculate the bounding rectangle for the tracker text from the current position of the tracker* **Parameters:** *font Font of the tracker text* **Returns:** *Bounding rectangle of the tracker text* **See also:** **trackerPosition()** ### QwtText QwtPicker::trackerText (const QPoint & pos) const` [virtual]` *Return the label for a position. In case of HLineRubberBand the label is the value of the y position, in case of VLineRubberBand the value of the x position. Otherwise the label contains x and y position separated by a ',' .* *The format for the string conversion is '%d'.* **Parameters:** *pos Position* **Returns:** *Converted position as string* *Reimplemented in* **QwtPlotPicker***.* ### void QwtPicker::transition (const QEvent \* event)` [protected]`, ` [virtual]` *Passes an event to the state machine and executes the resulting commands. Append and Move commands use the current position of the cursor ( QCursor::pos() ).* **Parameters:** *event Event* ### void QwtPicker::widgetEnterEvent (QEvent \* event)` [protected]`, ` [virtual]` *Handle a enter event for the observed widget.* **Parameters:** *event Qt event* **See also:** **eventFilter()***,* **widgetMousePressEvent()***,* **widgetMouseReleaseEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetWheelEvent()***,* **widgetKeyPressEvent()***,* **widgetKeyReleaseEvent()** ### void QwtPicker::widgetKeyPressEvent (QKeyEvent \* keyEvent)` [protected]`, ` [virtual]` *Handle a key press event for the observed widget.* *Selections can be completely done by the keyboard. The arrow keys move the cursor, the abort key aborts a selection. All other keys are handled by the current state machine.* **Parameters:** *keyEvent Key event* **See also:** **eventFilter()***,* **widgetMousePressEvent()***,* **widgetMouseReleaseEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetMouseMoveEvent()***,* **widgetWheelEvent()***,* **widgetKeyReleaseEvent()***,* **stateMachine()***,* **QwtEventPattern::KeyPatternCode** *Reimplemented in* **QwtPlotZoomer***.* ### void QwtPicker::widgetKeyReleaseEvent (QKeyEvent \* keyEvent)` [protected]`, ` [virtual]` *Handle a key release event for the observed widget.* *Passes the event to the state machine.* **Parameters:** *keyEvent Key event* **See also:** **eventFilter()***,* **widgetMousePressEvent()***,* **widgetMouseReleaseEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetMouseMoveEvent()***,* **widgetWheelEvent()***,* **widgetKeyPressEvent()***,* **stateMachine()** ### void QwtPicker::widgetLeaveEvent (QEvent \* event)` [protected]`, ` [virtual]` *Handle a leave event for the observed widget.* **Parameters:** *event Qt event* **See also:** **eventFilter()***,* **widgetMousePressEvent()***,* **widgetMouseReleaseEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetWheelEvent()***,* **widgetKeyPressEvent()***,* **widgetKeyReleaseEvent()** ### void QwtPicker::widgetMouseDoubleClickEvent (QMouseEvent \* mouseEvent)` [protected]`, ` [virtual]` *Handle mouse double click event for the observed widget.* **Parameters:** *mouseEvent Mouse event* **See also:** **eventFilter()***,* **widgetMousePressEvent()***,* **widgetMouseReleaseEvent()***,* **widgetMouseMoveEvent()***,* **widgetWheelEvent()***,* **widgetKeyPressEvent()***,* **widgetKeyReleaseEvent()** ### void QwtPicker::widgetMouseMoveEvent (QMouseEvent \* mouseEvent)` [protected]`, ` [virtual]` *Handle a mouse move event for the observed widget.* **Parameters:** *mouseEvent Mouse event* **See also:** **eventFilter()***,* **widgetMousePressEvent()***,* **widgetMouseReleaseEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetWheelEvent()***,* **widgetKeyPressEvent()***,* **widgetKeyReleaseEvent()** ### void QwtPicker::widgetMousePressEvent (QMouseEvent \* mouseEvent)` [protected]`, ` [virtual]` *Handle a mouse press event for the observed widget.* **Parameters:** *mouseEvent Mouse event* **See also:** **eventFilter()***,* **widgetMouseReleaseEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetMouseMoveEvent()***,* **widgetWheelEvent()***,* **widgetKeyPressEvent()***,* **widgetKeyReleaseEvent()** ### void QwtPicker::widgetMouseReleaseEvent (QMouseEvent \* mouseEvent)` [protected]`, ` [virtual]` *Handle a mouse release event for the observed widget.* **Parameters:** *mouseEvent Mouse event* **See also:** **eventFilter()***,* **widgetMousePressEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetMouseMoveEvent()***,* **widgetWheelEvent()***,* **widgetKeyPressEvent()***,* **widgetKeyReleaseEvent()** *Reimplemented in* **QwtPlotZoomer***.* ### void QwtPicker::widgetWheelEvent (QWheelEvent \* wheelEvent)` [protected]`, ` [virtual]` *Handle a wheel event for the observed widget.* *Move the last point of the selection in case of* **isActive()** *== true* **Parameters:** *wheelEvent Wheel event* **See also:** **eventFilter()***,* **widgetMousePressEvent()***,* **widgetMouseReleaseEvent()***,* **widgetMouseDoubleClickEvent()***,* **widgetMouseMoveEvent()***,* **widgetKeyPressEvent()***,* **widgetKeyReleaseEvent()** ## Author *Generated automatically by Doxygen for Qwt User's Guide from the source code.*