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

Inheritance diagram for QCPItemLine:

Public Member Functions
	QCPItemLine (QCustomPlot *parentPlot)
QPen	pen () const
QPen	selectedPen () const
QCPLineEnding	head () const
QCPLineEnding	tail () const
void	setPen (const QPen &pen)
void	setSelectedPen (const QPen &pen)
void	setHead (const QCPLineEnding &head)
void	setTail (const QCPLineEnding &tail)
virtual double	selectTest (const QPointF &pos, bool onlySelectable, QVariant *details=nullptr) const Q_DECL_OVERRIDE
Public Member Functions inherited from QCPAbstractItem
	QCPAbstractItem (QCustomPlot *parentPlot)
bool	clipToAxisRect () const
QCPAxisRect *	clipAxisRect () const
bool	selectable () const
bool	selected () const
void	setClipToAxisRect (bool clip)
void	setClipAxisRect (QCPAxisRect *rect)
Q_SLOT void	setSelectable (bool selectable)
Q_SLOT void	setSelected (bool selected)
QList< QCPItemPosition * >	positions () const
QList< QCPItemAnchor * >	anchors () const
QCPItemPosition *	position (const QString &name) const
QCPItemAnchor *	anchor (const QString &name) const
bool	hasAnchor (const QString &name) const
Public Member Functions inherited from QCPLayerable
	QCPLayerable (QCustomPlot plot, QString targetLayer=QString(), QCPLayerable parentLayerable=nullptr)
bool	visible () const
QCustomPlot *	parentPlot () const
QCPLayerable *	parentLayerable () const
QCPLayer *	layer () const
bool	antialiased () const
void	setVisible (bool on)
Q_SLOT bool	setLayer (QCPLayer *layer)
bool	setLayer (const QString &layerName)
void	setAntialiased (bool enabled)
bool	realVisibility () const

Public Attributes
QCPItemPosition *const	start
QCPItemPosition *const	end

Protected Member Functions
virtual void	draw (QCPPainter *painter) Q_DECL_OVERRIDE
QLineF	getRectClippedLine (const QCPVector2D &start, const QCPVector2D &end, const QRect &rect) const
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	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 void	mousePressEvent (QMouseEvent *event, const QVariant &details)
virtual void	mouseMoveEvent (QMouseEvent *event, const QPointF &startPos)
virtual void	mouseReleaseEvent (QMouseEvent *event, const QPointF &startPos)
virtual void	mouseDoubleClickEvent (QMouseEvent *event, const QVariant &details)
virtual void	wheelEvent (QWheelEvent *event)
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)
void	selectableChanged (bool selectable)
Signals inherited from QCPLayerable
void	layerChanged (QCPLayer *newLayer)

Detailed Description

A line from one point to another.

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

It has two positions, start and end, which define the end points of the line.

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

Constructor & Destructor Documentation

◆ QCPItemLine()

QCPItemLine::QCPItemLine ( QCustomPlot * parentPlot )

explicit

Creates a line 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 QCPItemLine::draw ( QCPPainter * painter )

protectedvirtual

Implements QCPAbstractItem.

◆ selectTest()

double QCPItemLine::selectTest	(	const QPointF &	pos,
		bool	onlySelectable,
		QVariant *	details = nullptr ) 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.

In the case of 1D Plottables (QCPAbstractPlottable1D, like QCPGraph or QCPBars) details will be set to a QCPDataSelection, describing the closest data point to pos.

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