A curved line from one point to another. More...

Inheritance diagram for QCPItemCurve:

Public Member Functions
	QCPItemCurve (QCustomPlot *parentPlot)
	Creates a curve item and sets default values.

QPen	pen () const

QPen	selectedPen () const

QCPLineEnding	head () const

QCPLineEnding	tail () const

void	setPen (const QPen &pen)
	Sets the pen that will be used to draw the line.

void	setSelectedPen (const QPen &pen)
	Sets the pen that will be used to draw the line when selected.

void	setHead (const QCPLineEnding &head)
	Sets the line ending style of the head.

void	setTail (const QCPLineEnding &tail)
	Sets the line ending style of the tail.

virtual double	selectTest (const QPointF &pos, bool onlySelectable, QVariant *details=0) const Q_DECL_OVERRIDE
	This function is used to decide whether a click hits a layerable object or not.

Public Member Functions inherited from QCPAbstractItem
	QCPAbstractItem (QCustomPlot *parentPlot)
	Base class constructor which initializes base class members.

bool	clipToAxisRect () const

QCPAxisRect *	clipAxisRect () const

bool	selectable () const

bool	selected () const

void	setClipToAxisRect (bool clip)
	Sets whether the item shall be clipped to an axis rect or whether it shall be visible on the entire QCustomPlot.

void	setClipAxisRect (QCPAxisRect *rect)
	Sets the clip axis rect.

Q_SLOT void	setSelectable (bool selectable)
	Sets whether the user can (de-)select this item by clicking on the QCustomPlot surface.

Q_SLOT void	setSelected (bool selected)
	Sets whether this item is selected or not.

virtual double	selectTest (const QPointF &pos, bool onlySelectable, QVariant *details=0) const Q_DECL_OVERRIDE=0
	This function is used to decide whether a click hits a layerable object or not.

QList< QCPItemPosition * >	positions () const
	Returns all positions of the item in a list.

QList< QCPItemAnchor * >	anchors () const
	Returns all anchors of the item in a list.

QCPItemPosition *	position (const QString &name) const
	Returns the QCPItemPosition with the specified name.

QCPItemAnchor *	anchor (const QString &name) const
	Returns the QCPItemAnchor with the specified name.

bool	hasAnchor (const QString &name) const
	Returns whether this item has an anchor with the specified name.

Public Member Functions inherited from QCPLayerable
	QCPLayerable (QCustomPlot plot, QString targetLayer=QString(), QCPLayerable parentLayerable=0)
	Creates a new QCPLayerable instance.

bool	visible () const

QCustomPlot *	parentPlot () const

QCPLayerable *	parentLayerable () const
	Returns the parent layerable of this layerable.

QCPLayer *	layer () const

bool	antialiased () const

void	setVisible (bool on)
	Sets the visibility of this layerable object.

Q_SLOT bool	setLayer (QCPLayer *layer)
	Sets the layer of this layerable object.

bool	setLayer (const QString &layerName)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Sets the layer of this layerable object by name.

void	setAntialiased (bool enabled)
	Sets whether this object will be drawn antialiased or not.

virtual double	selectTest (const QPointF &pos, bool onlySelectable, QVariant *details=0) const
	This function is used to decide whether a click hits a layerable object or not.

bool	realVisibility () const
	Returns whether this layerable is visible, taking the visibility of the layerable parent and the visibility of this layerable's layer into account.

Data Fields
QCPItemPosition *const	start

QCPItemPosition *const	startDir

QCPItemPosition *const	endDir

QCPItemPosition *const	end

Protected Member Functions
virtual void	draw (QCPPainter *painter) Q_DECL_OVERRIDE

QPen	mainPen () const

Protected Member Functions inherited from QCPAbstractItem
virtual QCP::Interaction	selectionCategory () const Q_DECL_OVERRIDE

virtual QRect	clipRect () const Q_DECL_OVERRIDE

virtual void	applyDefaultAntialiasingHint (QCPPainter *painter) const Q_DECL_OVERRIDE

virtual void	draw (QCPPainter *painter) Q_DECL_OVERRIDE=0

virtual void	selectEvent (QMouseEvent event, bool additive, const QVariant &details, bool selectionStateChanged) Q_DECL_OVERRIDE

virtual void	deselectEvent (bool *selectionStateChanged) Q_DECL_OVERRIDE

virtual QPointF	anchorPixelPosition (int anchorId) const

double	rectDistance (const QRectF &rect, const QPointF &pos, bool filledRect) const

QCPItemPosition *	createPosition (const QString &name)

QCPItemAnchor *	createAnchor (const QString &name, int anchorId)

Protected Member Functions inherited from QCPLayerable
virtual void	parentPlotInitialized (QCustomPlot *parentPlot)

virtual QCP::Interaction	selectionCategory () const

virtual QRect	clipRect () const

virtual void	applyDefaultAntialiasingHint (QCPPainter *painter) const =0

virtual void	draw (QCPPainter *painter)=0

virtual void	selectEvent (QMouseEvent event, bool additive, const QVariant &details, bool selectionStateChanged)

virtual void	deselectEvent (bool *selectionStateChanged)

virtual void	mousePressEvent (QMouseEvent *event, const QVariant &details)
	This event gets called when the user presses a mouse button while the cursor is over the layerable.

virtual void	mouseMoveEvent (QMouseEvent *event, const QPointF &startPos)
	This event gets called when the user moves the mouse while holding a mouse button, after this layerable has become the mouse grabber by accepting the preceding mousePressEvent.

virtual void	mouseReleaseEvent (QMouseEvent *event, const QPointF &startPos)
	This event gets called when the user releases the mouse button, after this layerable has become the mouse grabber by accepting the preceding mousePressEvent.

virtual void	mouseDoubleClickEvent (QMouseEvent *event, const QVariant &details)
	This event gets called when the user presses the mouse button a second time in a double-click, while the cursor is over the layerable.

virtual void	wheelEvent (QWheelEvent *event)
	This event gets called when the user turns the mouse scroll wheel while the cursor is over the layerable.

void	initializeParentPlot (QCustomPlot *parentPlot)

void	setParentLayerable (QCPLayerable *parentLayerable)

bool	moveToLayer (QCPLayer *layer, bool prepend)

void	applyAntialiasingHint (QCPPainter *painter, bool localAntialiased, QCP::AntialiasedElement overrideElement) const

Protected Attributes
QPen	mPen

QPen	mSelectedPen

QCPLineEnding	mHead

QCPLineEnding	mTail

Protected Attributes inherited from QCPAbstractItem
bool	mClipToAxisRect

QPointer< QCPAxisRect >	mClipAxisRect

QList< QCPItemPosition * >	mPositions

QList< QCPItemAnchor * >	mAnchors

bool	mSelectable

bool	mSelected

Protected Attributes inherited from QCPLayerable
bool	mVisible

QCustomPlot *	mParentPlot

QPointer< QCPLayerable >	mParentLayerable

QCPLayer *	mLayer

bool	mAntialiased

Additional Inherited Members
Signals inherited from QCPAbstractItem
void	selectionChanged (bool selected)
	This signal is emitted when the selection state of this item has changed, either by user interaction or by a direct call to setSelected.

void	selectableChanged (bool selectable)

Signals inherited from QCPLayerable
void	layerChanged (QCPLayer *newLayer)
	This signal is emitted when the layer of this layerable changes, i.e.

Detailed Description

A curved line from one point to another.

Curve example. Blue dotted circles are anchors, solid blue discs are positions.

It has four positions, start and end, which define the end points of the line, and two control points which define the direction the line exits from the start and the direction from which it approaches the end: startDir and endDir.

With setHead and setTail you may set different line ending styles, e.g. to create an arrow.

Often it is desirable for the control points to stay at fixed relative positions to the start/end point. This can be achieved by setting the parent anchor e.g. of startDir simply to start, and then specify the desired pixel offset with QCPItemPosition::setCoords on startDir.

Constructor & Destructor Documentation

◆ QCPItemCurve()

QCPItemCurve::QCPItemCurve ( QCustomPlot * parentPlot )

explicit

Creates a curve item and sets default values.

The created item is automatically registered with parentPlot. This QCustomPlot instance takes ownership of the item, so do not delete it manually but use QCustomPlot::removeItem() instead.

Member Function Documentation

◆ draw()

void QCPItemCurve::draw ( QCPPainter * painter )

protectedvirtual

Implements QCPAbstractItem.

◆ selectTest()

double QCPItemCurve::selectTest	(	const QPointF &	pos,
		bool	onlySelectable,
		QVariant *	details = `0`
	)		const

virtual

This function is used to decide whether a click hits a layerable object or not.

pos is a point in pixel coordinates on the QCustomPlot surface. This function returns the shortest pixel distance of this point to the object. If the object is either invisible or the distance couldn't be determined, -1.0 is returned. Further, if onlySelectable is true and the object is not selectable, -1.0 is returned, too.

If the object is represented not by single lines but by an area like a QCPItemText or the bars of a QCPBars plottable, a click inside the area should also be considered a hit. In these cases this function thus returns a constant value greater zero but still below the parent plot's selection tolerance. (typically the selectionTolerance multiplied by 0.99).

Providing a constant value for area objects allows selecting line objects even when they are obscured by such area objects, by clicking close to the lines (i.e. closer than 0.99*selectionTolerance).

The actual setting of the selection state is not done by this function. This is handled by the parent QCustomPlot when the mouseReleaseEvent occurs, and the finally selected object is notified via the selectEvent/ deselectEvent methods.

details is an optional output parameter. Every layerable subclass may place any information in details. This information will be passed to selectEvent when the parent QCustomPlot decides on the basis of this selectTest call, that the object was successfully selected. The subsequent call to selectEvent will carry the details. This is useful for multi-part objects (like QCPAxis). This way, a possibly complex calculation to decide which part was clicked is only done once in selectTest. The result (i.e. the actually clicked part) can then be placed in details. So in the subsequent selectEvent, the decision which part was selected doesn't have to be done a second time for a single selection operation.

You may pass 0 as details to indicate that you are not interested in those selection details.