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QCPItemBracket Class Reference

A bracket for referencing/highlighting certain parts in the plot. More...

Inheritance diagram for QCPItemBracket:
Inheritance graph

Public Types

enum  BracketStyle

Public Functions

 QCPItemBracket (QCustomPlot *parentPlot)
QPen pen () const
QPen selectedPen () const
double length () const
BracketStyle style () const
void setPen (const QPen &pen)
void setSelectedPen (const QPen &pen)
void setLength (double length)
void setStyle (BracketStyle style)
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 left
QCPItemPosition *const right
QCPItemAnchor *const center

Protected Types

enum  AnchorIndex

Protected Functions

virtual void draw (QCPPainter *painter)
virtual QPointF anchorPixelPosition (int anchorId) 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)
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 bracket for referencing/highlighting certain parts in the plot.

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

It has two positions, left and right, which define the span of the bracket. If left is actually farther to the left than right, the bracket is opened to the bottom, as shown in the example image.

The bracket supports multiple styles via setStyle. The length, i.e. how far the bracket stretches away from the embraced span, can be controlled with setLength.

Demonstrating the effect of different values for setLength, for styles bsCalligraphic and bsSquare. Anchors and positions are displayed for reference.

It provides an anchor center, to allow connection of other items, e.g. an arrow (QCPItemLine or QCPItemCurve) or a text label (QCPItemText), to the bracket.

Member Enumeration Documentation

§ BracketStyle

Defines the various visual shapes of the bracket item. The appearance can be further modified by setLength and setPen.

See also

A brace with angled edges.


A brace with round edges.


A curly brace.


A curly brace with varying stroke width giving a calligraphic impression.

Constructor & Destructor Documentation

§ QCPItemBracket()

QCPItemBracket::QCPItemBracket ( QCustomPlot parentPlot)

Creates a bracket 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 QCPItemBracket::setPen ( const QPen &  pen)

Sets the pen that will be used to draw the bracket.

Note that when the style is bsCalligraphic, only the color will be taken from the pen, the stroke and width are ignored. To change the apparent stroke width of a calligraphic bracket, use setLength, which has a similar effect.

See also

§ setSelectedPen()

void QCPItemBracket::setSelectedPen ( const QPen &  pen)

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

See also
setPen, setSelected

§ setLength()

void QCPItemBracket::setLength ( double  length)

Sets the length in pixels how far the bracket extends in the direction towards the embraced span of the bracket (i.e. perpendicular to the left-right-direction)

Demonstrating the effect of different values for setLength, for styles bsCalligraphic and bsSquare. Anchors and positions are displayed for reference.

§ setStyle()

void QCPItemBracket::setStyle ( QCPItemBracket::BracketStyle  style)

Sets the style of the bracket, i.e. the shape/visual appearance.

See also

§ selectTest()

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

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 QCPItemBracket::draw ( QCPPainter painter)

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.

§ anchorPixelPosition()

QPointF QCPItemBracket::anchorPixelPosition ( int  anchorId) const

Returns the pixel position of the anchor with Id anchorId. This function must be reimplemented in item subclasses if they want to provide anchors (QCPItemAnchor).

For example, if the item has two anchors with id 0 and 1, this function takes one of these anchor ids and returns the respective pixel points of the specified anchor.

See also

Reimplemented from QCPAbstractItem.

§ mainPen()

QPen QCPItemBracket::mainPen ( ) const

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: