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QCPItemLine Class Reference

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

Inheritance diagram for QCPItemLine:
Inheritance graph

Public 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
 
- Public Functions inherited from QCPAbstractItem
 QCPAbstractItem (QCustomPlot *parentPlot)
 
bool clipToAxisRect () const
 
QCPAxisRectclipAxisRect () 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
 
QCPItemPositionposition (const QString &name) const
 
QCPItemAnchoranchor (const QString &name) const
 
bool hasAnchor (const QString &name) const
 
- Public Functions inherited from QCPLayerable
 QCPLayerable (QCustomPlot *plot, QString targetLayer=QString(), QCPLayerable *parentLayerable=nullptr)
 
bool visible () const
 
QCustomPlotparentPlot () const
 
QCPLayerableparentLayerable () const
 
QCPLayerlayer () 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 Members

QCPItemPosition *const start
 
QCPItemPosition *const end
 

Protected Functions

virtual void draw (QCPPainter *painter)
 
QLineF getRectClippedLine (const QCPVector2D &start, const QCPVector2D &end, const QRect &rect) const
 
QPen mainPen () const
 
- Protected Functions inherited from QCPAbstractItem
virtual QCP::Interaction selectionCategory () const
 
virtual QRect clipRect () const
 
virtual void applyDefaultAntialiasingHint (QCPPainter *painter) const
 
virtual void selectEvent (QMouseEvent *event, bool additive, const QVariant &details, bool *selectionStateChanged)
 
virtual void deselectEvent (bool *selectionStateChanged)
 
virtual QPointF anchorPixelPosition (int anchorId) const
 
double rectDistance (const QRectF &rect, const QPointF &pos, bool filledRect) const
 
QCPItemPositioncreatePosition (const QString &name)
 
QCPItemAnchorcreateAnchor (const QString &name, int anchorId)
 
- Protected 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
 

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.

QCPItemLine.png
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

§ setPen()

void QCPItemLine::setPen ( const QPen &  pen)

Sets the pen that will be used to draw the line

See also
setSelectedPen

§ setSelectedPen()

void QCPItemLine::setSelectedPen ( const QPen &  pen)

Sets the pen that will be used to draw the line when selected

See also
setPen, setSelected

§ setHead()

void QCPItemLine::setHead ( const QCPLineEnding head)

Sets the line ending style of the head. The head corresponds to the end position.

Note that due to the overloaded QCPLineEnding constructor, you may directly specify a QCPLineEnding::EndingStyle here, e.g.

See also
setTail

§ setTail()

void QCPItemLine::setTail ( const QCPLineEnding tail)

Sets the line ending style of the tail. The tail corresponds to the start position.

Note that due to the overloaded QCPLineEnding constructor, you may directly specify a QCPLineEnding::EndingStyle here, e.g.

See also
setHead

§ 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.

See also
selectEvent, deselectEvent, mousePressEvent, wheelEvent, QCustomPlot::setInteractions, QCPAbstractPlottable1D::selectTestRect

Implements QCPAbstractItem.

§ draw()

void QCPItemLine::draw ( QCPPainter painter)
protectedvirtual

Draws this item with the provided painter.

The cliprect of the provided painter is set to the rect returned by clipRect before this function is called. The clipRect depends on the clipping settings defined by setClipToAxisRect and setClipAxisRect.

Implements QCPAbstractItem.

§ getRectClippedLine()

QLineF QCPItemLine::getRectClippedLine ( const QCPVector2D start,
const QCPVector2D end,
const QRect &  rect 
) const
protected

Returns the section of the line defined by start and end, that is visible in the specified rect.

This is a helper function for draw.

§ mainPen()

QPen QCPItemLine::mainPen ( ) const
protected

Returns the pen that should be used for drawing lines. Returns mPen when the item is not selected and mSelectedPen when it is.


The documentation for this class was generated from the following files: