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QCPItemText Class Reference

A text label. More...

Inheritance diagram for QCPItemText:
Inheritance graph

Public Functions

 QCPItemText (QCustomPlot *parentPlot)
QColor color () const
QColor selectedColor () const
QPen pen () const
QPen selectedPen () const
QBrush brush () const
QBrush selectedBrush () const
QFont font () const
QFont selectedFont () const
QString text () const
Qt::Alignment positionAlignment () const
Qt::Alignment textAlignment () const
double rotation () const
QMargins padding () const
void setColor (const QColor &color)
void setSelectedColor (const QColor &color)
void setPen (const QPen &pen)
void setSelectedPen (const QPen &pen)
void setBrush (const QBrush &brush)
void setSelectedBrush (const QBrush &brush)
void setFont (const QFont &font)
void setSelectedFont (const QFont &font)
void setText (const QString &text)
void setPositionAlignment (Qt::Alignment alignment)
void setTextAlignment (Qt::Alignment alignment)
void setRotation (double degrees)
void setPadding (const QMargins &padding)
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 position
QCPItemAnchor *const topLeft
QCPItemAnchor *const top
QCPItemAnchor *const topRight
QCPItemAnchor *const right
QCPItemAnchor *const bottomRight
QCPItemAnchor *const bottom
QCPItemAnchor *const bottomLeft
QCPItemAnchor *const left

Protected Types

enum  AnchorIndex

Protected Functions

virtual void draw (QCPPainter *painter)
virtual QPointF anchorPixelPosition (int anchorId) const
QPointF getTextDrawPoint (const QPointF &pos, const QRectF &rect, Qt::Alignment positionAlignment) const
QFont mainFont () const
QColor mainColor () const
QPen mainPen () const
QBrush mainBrush () 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 text label.

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

Its position is defined by the member position and the setting of setPositionAlignment. The latter controls which part of the text rect shall be aligned with position.

The text alignment itself (i.e. left, center, right) can be controlled with setTextAlignment.

The text may be rotated around the position point with setRotation.

Constructor & Destructor Documentation

§ QCPItemText()

QCPItemText::QCPItemText ( QCustomPlot parentPlot)

Creates a text 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

§ setColor()

void QCPItemText::setColor ( const QColor &  color)

Sets the color of the text.

§ setSelectedColor()

void QCPItemText::setSelectedColor ( const QColor &  color)

Sets the color of the text that will be used when the item is selected.

§ setPen()

void QCPItemText::setPen ( const QPen &  pen)

Sets the pen that will be used do draw a rectangular border around the text. To disable the border, set pen to Qt::NoPen.

See also
setSelectedPen, setBrush, setPadding

§ setSelectedPen()

void QCPItemText::setSelectedPen ( const QPen &  pen)

Sets the pen that will be used do draw a rectangular border around the text, when the item is selected. To disable the border, set pen to Qt::NoPen.

See also

§ setBrush()

void QCPItemText::setBrush ( const QBrush &  brush)

Sets the brush that will be used do fill the background of the text. To disable the background, set brush to Qt::NoBrush.

See also
setSelectedBrush, setPen, setPadding

§ setSelectedBrush()

void QCPItemText::setSelectedBrush ( const QBrush &  brush)

Sets the brush that will be used do fill the background of the text, when the item is selected. To disable the background, set brush to Qt::NoBrush.

See also

§ setFont()

void QCPItemText::setFont ( const QFont &  font)

Sets the font of the text.

See also
setSelectedFont, setColor

§ setSelectedFont()

void QCPItemText::setSelectedFont ( const QFont &  font)

Sets the font of the text that will be used when the item is selected.

See also

§ setText()

void QCPItemText::setText ( const QString &  text)

Sets the text that will be displayed. Multi-line texts are supported by inserting a line break character, e.g. '

See also
setFont, setColor, setTextAlignment

§ setPositionAlignment()

void QCPItemText::setPositionAlignment ( Qt::Alignment  alignment)

Sets which point of the text rect shall be aligned with position.


  • If alignment is Qt::AlignHCenter | Qt::AlignTop, the text will be positioned such that the top of the text rect will be horizontally centered on position.
  • If alignment is Qt::AlignLeft | Qt::AlignBottom, position will indicate the bottom left corner of the text rect.

If you want to control the alignment of (multi-lined) text within the text rect, use setTextAlignment.

§ setTextAlignment()

void QCPItemText::setTextAlignment ( Qt::Alignment  alignment)

Controls how (multi-lined) text is aligned inside the text rect (typically Qt::AlignLeft, Qt::AlignCenter or Qt::AlignRight).

§ setRotation()

void QCPItemText::setRotation ( double  degrees)

Sets the angle in degrees by which the text (and the text rectangle, if visible) will be rotated around position.

§ setPadding()

void QCPItemText::setPadding ( const QMargins &  padding)

Sets the distance between the border of the text rectangle and the text. The appearance (and visibility) of the text rectangle can be controlled with setPen and setBrush.

§ selectTest()

double QCPItemText::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 QCPItemText::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 QCPItemText::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.

§ getTextDrawPoint()

QPointF QCPItemText::getTextDrawPoint ( const QPointF &  pos,
const QRectF &  rect,
Qt::Alignment  positionAlignment 
) const

Returns the point that must be given to the QPainter::drawText function (which expects the top left point of the text rect), according to the position pos, the text bounding box rect and the requested positionAlignment.

For example, if positionAlignment is Qt::AlignLeft | Qt::AlignBottom the returned point will be shifted upward by the height of rect, starting from pos. So if the text is finally drawn at that point, the lower left corner of the resulting text rect is at pos.

§ mainFont()

QFont QCPItemText::mainFont ( ) const

Returns the font that should be used for drawing text. Returns mFont when the item is not selected and mSelectedFont when it is.

§ mainColor()

QColor QCPItemText::mainColor ( ) const

Returns the color that should be used for drawing text. Returns mColor when the item is not selected and mSelectedColor when it is.

§ mainPen()

QPen QCPItemText::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.

§ mainBrush()

QBrush QCPItemText::mainBrush ( ) const

Returns the brush that should be used for drawing fills of the item. Returns mBrush when the item is not selected and mSelectedBrush when it is.

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