QwtPicker provides selections on a widget. More...

#include <qwt_picker.h>

Inheritance diagram for QwtPicker:

Public Types
enum	RubberBand { NoRubberBand = 0 , HLineRubberBand , VLineRubberBand , CrossRubberBand , RectRubberBand , EllipseRubberBand , PolygonRubberBand , UserRubberBand = 100 }

enum	DisplayMode { AlwaysOff , AlwaysOn , ActiveOnly }
	Display mode. More...

enum	ResizeMode { Stretch , KeepSize }

Public Types inherited from QwtEventPattern
enum	MousePatternCode { MouseSelect1 , MouseSelect2 , MouseSelect3 , MouseSelect4 , MouseSelect5 , MouseSelect6 , MousePatternCount }
	Symbolic mouse input codes. More...

enum	KeyPatternCode { KeySelect1 , KeySelect2 , KeyAbort , KeyLeft , KeyRight , KeyUp , KeyDown , KeyRedo , KeyUndo , KeyHome , KeyPatternCount }
	Symbolic keyboard input codes. More...

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 ) override
	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	trackerMask () 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

Public Member Functions inherited from QwtEventPattern
	QwtEventPattern ()

virtual	~QwtEventPattern ()
	Destructor.

void	initMousePattern (int numButtons)

void	initKeyPattern ()

void	setMousePattern (MousePatternCode, Qt::MouseButton button, Qt::KeyboardModifiers=Qt::NoModifier)

void	setKeyPattern (KeyPatternCode, int key, Qt::KeyboardModifiers modifiers=Qt::NoModifier)

void	setMousePattern (const QVector< MousePattern > &)
	Change the mouse event patterns.

void	setKeyPattern (const QVector< KeyPattern > &)
	Change the key event patterns.

const QVector< MousePattern > &	mousePattern () const

const QVector< KeyPattern > &	keyPattern () const

QVector< MousePattern > &	mousePattern ()

QVector< KeyPattern > &	keyPattern ()

bool	mouseMatch (MousePatternCode, const QMouseEvent *) const
	Compare a mouse event with an event pattern.

bool	keyMatch (KeyPatternCode, const QKeyEvent *) const
	Compare a key event with an event pattern.

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

QRect	trackerRect (const QSize &) const

Protected Member Functions inherited from QwtEventPattern
virtual bool	mouseMatch (const MousePattern &, const QMouseEvent *) const
	Compare a mouse event with an event pattern.

virtual bool	keyMatch (const KeyPattern &, const QKeyEvent *) const
	Compare a key event with an event pattern.

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 <qwt_picker.h>

#include <qwt_picker_machine.h>

QwtPicker *picker = new QwtPicker(widget);

picker->setStateMachine(new QwtPickerDragRectMachine);

picker->setTrackerMode(QwtPicker::ActiveOnly);

picker->setRubberBand(QwtPicker::RectRubberBand);

QwtPickerDragRectMachine
A state machine for rectangle selections.
Definition qwt_picker_machine.h:162

QwtPicker
QwtPicker provides selections on a widget.
Definition qwt_picker.h:104

QwtPicker::ActiveOnly
@ ActiveOnly
Display only when the selection is active.
Definition qwt_picker.h:170

QwtPicker::setStateMachine
void setStateMachine(QwtPickerMachine *)
Definition qwt_picker.cpp:230

QwtPicker::setRubberBand
void setRubberBand(RubberBand)
Definition qwt_picker.cpp:290

QwtPicker::setTrackerMode
void setTrackerMode(DisplayMode)
Set the display mode of the tracker.
Definition qwt_picker.cpp:320

QwtPicker::RectRubberBand
@ RectRubberBand
A rectangle ( only for QwtPickerMachine::RectSelection )
Definition qwt_picker.h:142

QwtPicker::QwtPicker
QwtPicker(QWidget *parent)
Definition qwt_picker.cpp:169

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.

Definition at line 103 of file qwt_picker.h.

Member Enumeration Documentation

◆ DisplayMode

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.

Definition at line 161 of file qwt_picker.h.

◆ ResizeMode

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.

Definition at line 181 of file qwt_picker.h.

◆ RubberBand

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.

Definition at line 127 of file qwt_picker.h.

Constructor & Destructor Documentation

◆ QwtPicker() [1/2]

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

Definition at line 169 of file qwt_picker.cpp.

◆ QwtPicker() [2/2]

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

Definition at line 182 of file qwt_picker.cpp.

◆ ~QwtPicker()

QwtPicker::~QwtPicker ( )

virtual

Destructor.

Definition at line 190 of file qwt_picker.cpp.

Member Function Documentation

◆ accept()

bool QwtPicker::accept ( QPolygon & selection ) const

protectedvirtual

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.

Definition at line 1402 of file qwt_picker.cpp.

◆ activated

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

◆ adjustedPoints()

QPolygon QwtPicker::adjustedPoints ( const QPolygon & points ) const

protectedvirtual

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

Definition at line 783 of file qwt_picker.cpp.

◆ append()

void QwtPicker::append ( const QPoint & pos )

protectedvirtual

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, and QwtPolarPicker.

Definition at line 1339 of file qwt_picker.cpp.

◆ appended

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()

◆ begin()

void QwtPicker::begin ( )

protectedvirtual

Open a selection setting the state to active

See also: isActive(), end(), append(), move()

Reimplemented in QwtPlotZoomer.

Definition at line 1258 of file qwt_picker.cpp.

◆ changed

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()

◆ drawRubberBand()

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

Definition at line 637 of file qwt_picker.cpp.

◆ drawTracker()

void QwtPicker::drawTracker ( QPainter * painter ) const

virtual

Draw the tracker

Parameters

painter Painter

See also: trackerRect(), trackerText()

Definition at line 732 of file qwt_picker.cpp.

◆ end()

bool QwtPicker::end ( bool ok = true )

protectedvirtual

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 QwtPlotPicker, QwtPlotZoomer, and QwtPolarPicker.

Definition at line 1291 of file qwt_picker.cpp.

◆ eventFilter()

bool QwtPicker::eventFilter	(	QObject *	object,
		QEvent *	event )

overridevirtual

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()

Definition at line 912 of file qwt_picker.cpp.

◆ isActive()

bool QwtPicker::isActive ( ) const

A picker is active between begin() and end().

Returns: true if the selection is active.

Definition at line 1412 of file qwt_picker.cpp.

◆ isEnabled()

bool QwtPicker::isEnabled ( ) const

Returns: true when enabled, false otherwise

See also: setEnabled(), eventFilter()

Definition at line 400 of file qwt_picker.cpp.

◆ move()

void QwtPicker::move ( const QPoint & pos )

protectedvirtual

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, and QwtPolarPicker.

Definition at line 1357 of file qwt_picker.cpp.

◆ moved

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()

◆ parentWidget() [1/2]

QWidget * QwtPicker::parentWidget ( )

Return the parent widget, where the selection happens.

Definition at line 263 of file qwt_picker.cpp.

◆ parentWidget() [2/2]

const QWidget * QwtPicker::parentWidget ( ) const

Return the parent widget, where the selection happens.

Definition at line 273 of file qwt_picker.cpp.

◆ pickArea()

QPainterPath QwtPicker::pickArea ( ) const

virtual

Find the area of the observed widget, where selection might happen.

Returns: parentWidget()->contentsRect()

Reimplemented in QwtPolarPicker.

Definition at line 1493 of file qwt_picker.cpp.

◆ pickedPoints()

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

Definition at line 1422 of file qwt_picker.cpp.

◆ remove()

void QwtPicker::remove ( )

Public Types

Public Slots

Signals

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ DisplayMode

◆ ResizeMode

◆ RubberBand

Constructor & Destructor Documentation

◆ QwtPicker() [1/2]

◆ QwtPicker() [2/2]

◆ ~QwtPicker()

Member Function Documentation

◆ accept()

◆ activated

◆ adjustedPoints()

◆ append()

◆ appended

◆ begin()

◆ changed

◆ drawRubberBand()

◆ drawTracker()

◆ end()

◆ eventFilter()

◆ isActive()

◆ isEnabled()

◆ move()

◆ moved

◆ parentWidget() [1/2]

◆ parentWidget() [2/2]

◆ pickArea()

◆ pickedPoints()

◆ remove()