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Referencia de la Clase QCPItemTracer

Item that sticks to QCPGraph data points. Más...

Diagrama de herencias de QCPItemTracer
QCPAbstractItem QCPLayerable

Tipos públicos

enum  TracerStyle {
  tsNone, tsPlus, tsCrosshair, tsCircle,
  tsSquare
}
 

Métodos públicos

 QCPItemTracer (QCustomPlot *parentPlot)
 
QPen pen () const
 
QPen selectedPen () const
 
QBrush brush () const
 
QBrush selectedBrush () const
 
double size () const
 
TracerStyle style () const
 
QCPGraphgraph () const
 
double graphKey () const
 
bool interpolating () const
 
void setPen (const QPen &pen)
 
void setSelectedPen (const QPen &pen)
 
void setBrush (const QBrush &brush)
 
void setSelectedBrush (const QBrush &brush)
 
void setSize (double size)
 
void setStyle (TracerStyle style)
 
void setGraph (QCPGraph *graph)
 
void setGraphKey (double key)
 
void setInterpolating (bool enabled)
 
virtual double selectTest (const QPointF &pos, bool onlySelectable, QVariant *details=0) const
 
void updatePosition ()
 
- Métodos públicos heredados desde QCPAbstractItem
 QCPAbstractItem (QCustomPlot *parentPlot)
 
bool clipToAxisRect () const
 
QCPAxisRectclipAxisRect () const
 
bool selectable () const
 
bool selected () const
 
void setClipToAxisRect (bool clip)
 
void setClipAxisRect (QCPAxisRect *rect)
 
void setSelectable (bool selectable)
 
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
 
- Métodos públicos heredados desde QCPLayerable
 QCPLayerable (QCustomPlot *plot, QString targetLayer="", QCPLayerable *parentLayerable=0)
 
bool visible () const
 
QCustomPlotparentPlot () const
 
QCPLayerableparentLayerable () const
 
QCPLayerlayer () const
 
bool antialiased () const
 
void setVisible (bool on)
 
bool setLayer (QCPLayer *layer)
 
bool setLayer (const QString &layerName)
 
void setAntialiased (bool enabled)
 
bool realVisibility () const
 

Atributos públicos

QCPItemPosition *const position
 

Métodos protegidos

virtual void draw (QCPPainter *painter)
 
QPen mainPen () const
 
QBrush mainBrush () const
 
- Métodos protegidos heredados desde 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 anchorPixelPoint (int anchorId) const
 
double distSqrToLine (const QPointF &start, const QPointF &end, const QPointF &point) const
 
double rectSelectTest (const QRectF &rect, const QPointF &pos, bool filledRect) const
 
QCPItemPositioncreatePosition (const QString &name)
 
QCPItemAnchorcreateAnchor (const QString &name, int anchorId)
 
- Métodos protegidos heredados desde QCPLayerable
virtual void parentPlotInitialized (QCustomPlot *parentPlot)
 
void initializeParentPlot (QCustomPlot *parentPlot)
 
void setParentLayerable (QCPLayerable *parentLayerable)
 
bool moveToLayer (QCPLayer *layer, bool prepend)
 
void applyAntialiasingHint (QCPPainter *painter, bool localAntialiased, QCP::AntialiasedElement overrideElement) const
 

Atributos protegidos

QPen mPen
 
QPen mSelectedPen
 
QBrush mBrush
 
QBrush mSelectedBrush
 
double mSize
 
TracerStyle mStyle
 
QCPGraphmGraph
 
double mGraphKey
 
bool mInterpolating
 
- Atributos protegidos heredados desde QCPAbstractItem
bool mClipToAxisRect
 
QPointer< QCPAxisRectmClipAxisRect
 
QList< QCPItemPosition * > mPositions
 
QList< QCPItemAnchor * > mAnchors
 
bool mSelectable
 
bool mSelected
 
- Atributos protegidos heredados desde QCPLayerable
bool mVisible
 
QCustomPlotmParentPlot
 
QPointer< QCPLayerablemParentLayerable
 
QCPLayermLayer
 
bool mAntialiased
 

Otros miembros heredados

- Señales heredados desde QCPAbstractItem
void selectionChanged (bool selected)
 

Descripción detallada

Item that sticks to QCPGraph data points.

QCPItemTracer.png
Tracer example. Blue dotted circles are anchors, solid blue discs are positions.

The tracer can be connected with a QCPGraph via setGraph. Then it will automatically adopt the coordinate axes of the graph and update its position to be on the graph's data. This means the key stays controllable via setGraphKey, but the value will follow the graph data. If a QCPGraph is connected, note that setting the coordinates of the tracer item directly via position will have no effect because they will be overriden in the next redraw (this is when the coordinate update happens).

If the specified key in setGraphKey is outside the key bounds of the graph, the tracer will stay at the corresponding end of the graph.

With setInterpolating you may specify whether the tracer may only stay exactly on data points or whether it interpolates data points linearly, if given a key that lies between two data points of the graph.

The tracer has different visual styles, see setStyle. It is also possible to make the tracer have no own visual appearance (set the style to tsNone), and just connect other item positions to the tracer position (used as an anchor) via QCPItemPosition::setParentAnchor.

Nota
The tracer position is only automatically updated upon redraws. So when the data of the graph changes and immediately afterwards (without a redraw) the a position coordinates of the tracer are retrieved, they will not reflect the updated data of the graph. In this case updatePosition must be called manually, prior to reading the tracer coordinates.

Documentación de las enumeraciones miembro de la clase

The different visual appearances a tracer item can have. Some styles size may be controlled with setSize.

Ver también
setStyle
Valores de enumeraciones
tsNone 

The tracer is not visible.

tsPlus 

A plus shaped crosshair with limited size.

tsCrosshair 

A plus shaped crosshair which spans the complete axis rect.

tsCircle 

A circle.

tsSquare 

A square.

Documentación del constructor y destructor

QCPItemTracer::QCPItemTracer ( QCustomPlot parentPlot)

Creates a tracer item and sets default values.

The constructed item can be added to the plot with QCustomPlot::addItem.

Documentación de las funciones miembro

double QCPItemTracer::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 item is represented not by single lines but by an area like QCPItemRect or QCPItemText, a click inside the area returns a constant value greater zero (typically the selectionTolerance of the parent QCustomPlot multiplied by 0.99). If the click lies outside the area, this function returns -1.0.

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.

Ver también
selectEvent, deselectEvent, QCustomPlot::setInteractions

Implementa QCPAbstractItem.

void QCPItemTracer::setBrush ( const QBrush &  brush)

Sets the brush that will be used to draw any fills of the tracer

Ver también
setSelectedBrush, setPen
void QCPItemTracer::setGraph ( QCPGraph graph)

Sets the QCPGraph this tracer sticks to. The tracer position will be set to type QCPItemPosition::ptPlotCoords and the axes will be set to the axes of graph.

To free the tracer from any graph, set graph to 0. The tracer position can then be placed freely like any other item position. This is the state the tracer will assume when its graph gets deleted while still attached to it.

Ver también
setGraphKey
void QCPItemTracer::setGraphKey ( double  key)

Sets the key of the graph's data point the tracer will be positioned at. This is the only free coordinate of a tracer when attached to a graph.

Depending on setInterpolating, the tracer will be either positioned on the data point closest to key, or will stay exactly at key and interpolate the value linearly.

Ver también
setGraph, setInterpolating
void QCPItemTracer::setInterpolating ( bool  enabled)

Sets whether the value of the graph's data points shall be interpolated, when positioning the tracer.

If enabled is set to false and a key is given with setGraphKey, the tracer is placed on the data point of the graph which is closest to the key, but which is not necessarily exactly there. If enabled is true, the tracer will be positioned exactly at the specified key, and the appropriate value will be interpolated from the graph's data points linearly.

Ver también
setGraph, setGraphKey
void QCPItemTracer::setPen ( const QPen &  pen)

Sets the pen that will be used to draw the line of the tracer

Ver también
setSelectedPen, setBrush
void QCPItemTracer::setSelectedBrush ( const QBrush &  brush)

Sets the brush that will be used to draw any fills of the tracer, when selected.

Ver también
setBrush, setSelected
void QCPItemTracer::setSelectedPen ( const QPen &  pen)

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

Ver también
setPen, setSelected
void QCPItemTracer::setSize ( double  size)

Sets the size of the tracer in pixels, if the style supports setting a size (e.g. tsSquare does, tsCrosshair does not).

void QCPItemTracer::setStyle ( QCPItemTracer::TracerStyle  style)

Sets the style/visual appearance of the tracer.

If you only want to use the tracer position as an anchor for other items, set style to tsNone.

void QCPItemTracer::updatePosition ( )

If the tracer is connected with a graph (setGraph), this function updates the tracer's position to reside on the graph data, depending on the configured key (setGraphKey).

It is called automatically on every redraw and normally doesn't need to be called manually. One exception is when you want to read the tracer coordinates via position and are not sure that the graph's data (or the tracer key with setGraphKey) hasn't changed since the last redraw. In that situation, call this function before accessing position, to make sure you don't get out-of-date coordinates.

If there is no graph set on this tracer, this function does nothing.


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